Pharmacology & Drug Classifications
Pharmacology (in Greek: pharmacon meaning drug, and logos meaning science) is the study of how chemical substances interact with living systems. If substances have medicinal properties, they are considered pharmaceuticals. The field encompasses drug composition and properties, interactions, toxicology, therapy, and medical applications and antipathogenic capabilities. The science is considered to have been invented by Arab physicians in Baghdad during the Golden Age of Islam; pharmacopoeias were penned in Arabic as early as the 7th century.
Pharmacology as a science is practiced by pharmacologists. Subdisciplines are clinical pharmacology (the medical field of medication effects on humans), neuro- and psychopharmacology (effects of medication on behavior and nervous system functioning), and theoretical pharmacology.
A drug is any chemical substance, other than a food or device, that affects the function of living things. Technically, vitamin E, oxygen, and cocaine are all examples of drugs. Various drugs can be used to treat illness, or they can be used recreationally to alter behavior and perception.
Drugs used as medicines
A medication is a licensed drug taken to cure or reduce symptoms of an illness or medical condition. Medications are generally divided into two groups -- over the counter (OTC) medications, which are available in pharmacies and supermarkets without special restrictions, and Prescription only medicines (POM), which must be prescribed by a physician. Most OTC medication is generally considered to be safe enough that most persons will not hurt themselves accidentally by taking it as instructed. Many countries, such as the UK have a third category of pharmacy medicines which can only be sold in registered pharmacies, by or under the supervision of a pharmacist. However, the precise distinction between OTC and prescription depends on the legal jurisdiction. Medications are typically produced by pharmaceutical companies and are often patented. Those that are not patented are called generic drugs.
Classification based on System response
Medication can be usually classified in various ways, e.g. by its chemical properties, mode of administration, or biological system affected. An elaborate and widely used classification system is the Anatomical Therapeutic Chemical Classification System.
Types Of Medication
For the gastrointestinal tract or digestive system
§ Upper digestive tract: antacids, reflux suppressants, antiflatulents, antidopaminergics, proton pump inhibitors, H2-receptor antagonists, cytoprotectants, prostaglandin analogues
§ Lower digestive tract: laxatives, antispasmodics, antidiarrhoeals, bile acid sequestrants, opioids
For the cardiovascular system
§ General: beta-receptor blocker, calcium channel blockers, diuretics, cardiac glycosides, antiarrhythmics, nitrate, Antianginals, vasoconstrictor, vasodilator, peripheral activator
§ Affecting Blood pressure: ACE inhibitors, angiotensin receptor blockers, alpha blocker
§ Coagulation: anticoagulant, heparin, antiplatelet drug, fibrinolytic, anti-hemophilic factor, hemostatic drugs
§ Atherosclerosis/cholesterol agents: hypolipidemic agents, statins.
For the central nervous system
Hypnotic, anesthetics, antipsychotic, antidepressant (including tricyclic antidepressants, monoamine oxidase inhibitor, lithium salt, selective serotonin reuptake inhibitor), anti-emetic, anticonvulsant and antiepileptic, anxiolytic, barbiturate, movement disorder drug, stimulant (including amphetamines), benzodiazepine, cyclopyrrolone, dopamine antagonist, antihistamine, cholinergic, anticholinergic, emetic, cannabinoids, 5-HT antagonist.
For pain & consciousness (Analgesic drugs)
The main classes of painkillers are NSAIDs, opioids and various orphans such as paracetamol, tricyclic antidepressants and anticonvulsants.
For musculoskeletal disorders
NSAIDs (including COX-2 selective inhibitors), muscle relaxant, neuromuscular drug
For the eye
§ General: adrenergic neurone blocker, astringent, ocular lubricant
§ Diagnostic: topical anesthetics, sympathomimetics, parasympatholytics, mydriatics, cycloplegics
§ Anti-bacterial: antibiotics, topical antibiotics, sulfa drugs, aminoglycosides, fluoroquinolones
§ Anti-fungal: imidazoles, polyenes
§ Anti-inflammatory: NSAIDs, corticosteroids
§ Anti-allergy: mast cell inhibitors
§ Anti-glaucoma: adrenergic agonists, beta-blockers, carbonic anhydrase inhibitors/hyperosmotics, cholinergics, miotics, parasympathomimetics, prostaglandin agonists/prostaglandin inhibitors. nitroglycerin
For the ear, nose and oropharynx
Sympathomimetic, antihistamine, anticholinergic, NSAIDs, steroid, antiseptic, local anesthetic, antifungal, ceruminolytic
For the respiratory system
§ bronchodilator, NSAIDs, anti-allergic, antitussive, mucolytic, decongestant
§ corticosteroid, beta-receptor antagonist, anticholinergic, steroid
For endocrine problems
androgen, antiandrogen, gonadotropin, corticosteroid, growth hormone, insulin, antidiabetic (sulfonylurea, biguanide/metformin, thiazolidinedione, insulin), thyroid hormones, antithyroid drugs, calcitonin, diphosphonate, vasopressin analogues
For the reproductive system or urinary system
antifungal, alkalising agent, quinolones, antibiotic, cholinergic, anticholinergic, anticholinesterase, antispasmodic, 5-alpha reductase inhibitor, selective alpha-1 blocker, sildenafil
contraceptive, oral contraceptives, spermicide, depot contraceptives
For obstetrics and gynecology
NSAIDs, anticholinergic, hemostatic drug, antifibrinolytic, Hormone Replacement Therapy, bone regulator, beta-receptor agonist, follicle stimulating hormone, luteinizing hormone, LHRH
gamolenic acid, gonadotropin release inhibitor, progestogen, dopamine agonist, oestrogen, prostaglandin, gonadorelin, clomiphene, tamoxifen, Diethylstilbestrol
For the skin
emollient, anti-pruritic, antifungal, disinfectant, scabicide, pediculicide, tar products, vitamin A derivatives, vitamin D analogue, keratolytic, abrasive, systemic antibiotic, topical antibiotic, hormones, desloughing agent, exudate absorbent, fibrinolytic, proteolytic, sunscreen, antiperspirant, corticosteroid
For infections and infestations
antibiotic, antifungal, antileprotic, antituberculous drug, antimalarial, anthelmintic, amoebicide, antiviral, antiprotozoal, antiserum
vaccine, immunoglobulin, immunosuppressant, interferon, monoclonal antibody
For allergic disorders
anti-allergic, antihistamine, NSAIDs
tonic, iron preparation, electrolyte, parenteral nutritional supplement, vitamins, anti-obesity drug, anabolic drug, hematopoietic drug, food product drug
For neoplastic disorders
cytotoxic drug, sex hormones, aromatase inhibitor, somatostatin inhibitor, recombinant interleukins, G-CSF, erythropoietin
The technical term placebo is precisely applied in the specialized medical domains of pharmacology, nosology, and aetiology to denote the pharmacologically inert, dummy simulator of an "active" drug that serves as a scientific control in clinical trials designed to determine the clinical efficacy of that particular drug
In particular, these clinical trials are conducted in order to determine whether a drug's supposedly active ingredients affect the subject through direct physiochemical processes or through mind-mediation.
Generic drug (pl. generic drugs, short: generics) is a drug which is bioequivalent to a brand name drug with respect to pharmacokinetic and pharmacodynamic properties, but is normally sold for a lower price. Generic medicines must contain the same active ingredient at the same strength as the "innovator" brand, be bioequivalent, and are required to meet the same pharmacopeial requirements for the preparation. By extension, therefore, generics are assumed to be identical in dose, strength, route of administration, safety, efficacy, and intended use.
The principal reason for the reduced cost of generic medicines is that these are manufactured by smaller pharmaceutical companies which do not invest in research and development into new drugs or massive television and radio advertising campaigns. Generic manufacturers also do not give away thousands of doses of their drugs for 'promotional purposes'.
Route Of Administration
In pharmacology and toxicology, a route of administration is the path by which a drug, fluid, poison or other substance is brought into contact with the body.
Obviously, a substance must be transported from the site of entry to the part of the body where its action is desired to take place (even if this only means penetration through the stratum corneum into the skin). However, using the body's transport mechanisms for this purpose can be far from trivial. The pharmacokinetic properties of a drug (that is, those related to processes of uptake, distribution, and elimination) are critically influenced by the route of administration.
Routes of administration can broadly be divided into:
§ topical: local effect, substance is applied directly where its action is desired
§ enteral: desired effect is systemic (non-local), substance is given via the digestive tract
§ parenteral: desired effect is systemic, substance is given by other routes than the digestive tract
The U.S. Food and Drug Administration recognizes 111 distinct routes of administration.
The following is a brief list of some routes of administration.
§ epicutaneous (application onto the skin), e.g. allergy testing, topical local anesthesia
§ inhalational, e.g. asthma medications
§ enema, e.g. contrast media for imaging of the bowel
§ eye drops (onto the conjunctiva), e.g. antibiotics for conjunctivitis
§ ear drops - such as antibiotics and corticosteroids for otitis externa
§ intranasal, e.g. decongestant nasal sprays
§ by mouth (orally), many drugs as tablets, capsules, or drops
§ by gastric feeding tube, duodenal feeding tube, or gastrostomy, many drugs and enteral nutrition
§ rectally, various drugs in suppository or enema form
Parenteral by injection or infusion
§ intravenous (into a vein), e.g. many drugs, total parenteral nutrition
§ intraarterial (into an artery), e.g. vasodilator drugs in the treatment of vasospasm and thrombolytic drugs for treatment of embolism
§ intramuscular (into a muscle), e.g. many vaccines, antibiotics, and long-term psychoactive agents.
§ intracardiac (into the heart), e.g. adrenaline during cardiopulmonary resuscitation (not commonly performed anymore)
§ subcutaneous (under the skin), e.g. insulin
§ intraosseous infusion (into the bone marrow) is, in effect, an indirect intravenous access because the bone marrow drains directly into the venous system. This route is occasionally used for drugs and fluids in emergency medicine and pediatrics when intravenous access is difficult
§ intradermal, (into the skin itself) is used for skin testing some allergens, and also for tattoos
§ intraperitoneal, (into the peritoneum) is predominantly used in veterinary medicine and animal testing for the administration of systemic drugs and fluids due to the ease of administration compared with other parenteral methods.
Parenteral (other than oral)
§ transdermal (diffusion through the intact skin), e.g. transdermal opioid patches in pain therapy
§ transmucosal (diffusion through a mucous membrane), e.g. cocaine snorting, sublingual nitroglycerine
§ inhalational, e.g. inhalational anesthetics
§ intraperitoneal (infusion or injection into the peritoneal cavity), e.g. peritoneal dialysis
§ epidural (synonym: peridural) (injection or infusion into the epidural space), e.g. epidural anesthesia
§ intrathecal (injection or infusion into the cerebrospinal fluid), e.g. antibiotics, spinal anesthesia
§ intravitreal - is a route of administration of a drug, or other substance, in which the substance is delivered via an eye. "Intravitreal" literally means "inside an eye".
Pharmaceutical form is the way the drugs are delivered to the patient.
Types of pharmaceutical forms (abbreviation, latin origin)
§ ampule (amp; lat. ampula)
§ capsule (cap., caps.; lat. capsula)
§ cream (cr., crm.)
§ elixir (elix.)
§ emulsion (emuls.; lat. emulsum)
§ fluid (fl., fld.; lat. fluidum)
§ grain (gr.)
§ drop(s) (gtt(s).; lat. gutta(e))
§ injection (inj.; lat. injectio)
§ solution (liq.; lat. liquor)
§ solution (sol.; lat. solutio)
§ lotion (lot.; lat. lotio)
§ a spray (nebul.; lat. nebula)
§ powder (pulv.; lat. pulvis)
§ suspension (susp.; lat. suspensio)
§ syrup (syr.; lat. syrupus)
§ tablet (tab.; lat. tabella)
§ tincture (tr., tinc., tinct.; lat. tinctura)
§ ointment (ung.; lat. unguentum)
An injection is a method of putting liquid into the body with a hollow needle and a syringe, which is pierced through the skin long enough for the material to be forced into the body. An injection follows a parenteral route of administration, that is, its effect is not necessarily local to the area in which the injection is administered; it is systematic.
There are generally three types of injections-subcutaneous injections, intramuscular injections, and intravenous infusions.
A subcutaneous injection is administered into the subcutis, the layer of skin directly below the dermis and epidermis, collectively referred to as the cutis. Subcutaneous injections are highly effective in administering such medications as insulin or goserelin.
A person with Type I diabetes mellitus typically injects insulin subcutaneously. Places on the body where people can inject insulin most easily are:
§ The outer area of the upper arm.
§ Just above and below the waist, except the area right around the navel (a 2-inch circle).
§ The upper area of the buttock, just behind the hip bone.
§ The front of the thigh, midway to the outer side, 4 inches below the top of the thigh to 4 inches above the knee.
These areas can vary with the size of the person. Changing the injection site keeps lumps or small dents called lipodystrophies from forming in the skin. However, people should try to use the same body area for injections that are given at the same time each day-for example, always using the stomach for the morning injection or an arm for the evening injection. Using the same body area for these routine injections lessens the possibility of changes in the timing and action of insulin.
An intramuscular injection is a substance injected directly into a muscle. Many vaccines are administered intramuscularly, as well as codeine, metoclopramide, and many other medications. Many drugs injected intramuscularly are absorbed into the muscle fairly quickly, while others are more gradual.
Generally, intramuscular injections are not self-administered, but rather by a trained medical professional. However, prescribed self-administered intramuscular injections are perhaps becoming more common with time for patients that require these injections on a routine basis.
An intravenous infusion is a liquid administered directly into the bloodstream via a vein. The first polio vaccine in 1952 was injected intravenously until an oral vaccine replaced it in 1955.
There are other types of injections too like
§ Intracardiac injection
§ Intradermal injection
§ Intraosseous infusion
§ Intraarterial injection
The action of drugs on the human body is called pharmacodynamics, and what the body does with the drug is called pharmacokinetics. The drugs that enter the human tend to stimulate certain receptors, ion channels, act on enzymes or transporter proteins. As a result, they cause the human body to reaction in a specific way.
There are two different types of drugs:
§ Agonists - they stimulate and activate the receptors
§ Antagonists - they stop the agonists from stimulating the receptors
Once the receptors are activated, they either trigger a particular response directly on the body, or they trigger the release of hormones and/or other endogenous drugs in the body to stimulate a particular response.
Adverse drug reaction/Drug toxicity
An adverse drug reaction (abbreviated ADR) is a term to describe the unwanted, negative consequences sometimes associated with the use of medications. ADR is a particular type of adverse effect. The term is preferred over the colloquial and imprecise "side effect", as the term "side effect" implies the potential for beneficial consequences and that the effects are not explained by the pharmacological actions of the drug.
While ADR is probably the most precise term to describe the concept, it is not widely used in the community since it may be perceived as jargon and because of the negative-associations with the term "drug". Alternative terms with equivalent meaning to ADR include: side effect, adverse event, adverse effect, etc.
There are many types of ADRs:
§ Type A, pharmacologically predictable
§ Type B, bizarre and unpredictable
§ Type C, arising from chronic use
§ Type D, delayed reaction
§ Type E, end of dose reaction
§ Type F, Failure of therapy
Iatrogenesis literally means "brought forth by a healer" (iatros means healer in Greek); as such, it can refer to good or bad effects, but it is almost exclusively used to refer to the causation of a state of ill health or adverse effect or complication caused by or resulting from medical treatment.
There are many sources of iatrogenesis:
§ physician error
§ prescription drug interaction
§ adverse effects of prescription drugs
§ unproven or radical treatments
§ biased diagnosis
§ nosocomial infection
§ medical torture
§ unethical medical experimentation
In medicine, a contraindication is a condition or factor that increases the risk involved in using a particular drug, carrying out a medical procedure or engaging in a particular activity.
§ An absolute contraindication is a condition that prohibits the use of a treatment altogether. For example, an untreated pneumothorax would be an absolute contraindication to hyperbaric oxygen therapy.
§ A relative contraindication weighs in against the use of a treatment when assessing its risk/benefit ratio.
Drug Dosing Terminology
These are some of the most commonly used drug abbreviations:
a.c. before meals or food
b.i.d. twice daily
h.s. at bedtime
p.c. after meals
p.o. by mouth
p.r.n. as needed
O.D. right eye
O.S. left eye
O.U. each eye
q.o.d. every other day
q.h. every hour
q.4h. every four hours
q.8h. every eight hours
q.i.d. four times a day
q.o.d. every other day
t.i.d. three times a day
Some Dos and Donts in drug prescription:
q. four hours q.4h.
.80 mg 0.80 mg
five hundred mg 500 mg
Acne Vulgaris Drugs
These drugs control the inflammatory eruptions composed of cysts, papules, and comedones, predominantly on the face, upper back, and chest. The condition occurs in a majority of people during puberty and adolescence. Examples: Benzoyl peroxide, tretinoin, Ultra, Olux, and topical erythromycin.
Anabolic agents are the ones, which can stimulate growth of muscle mass. They are the compounds with androgenic properties and are used in severe cases of emaciation and most prominently by athletes to increase their muscle size, strength, and endurance. Some of the examples are Histerone 100, Depo-Testosterone, Malogen, etc.
Analgesics or as the name suggests are drugs, which have the property of reducing the pain or rather producing a neurologic and pharmacologic state in which the painful stimuli are blunted so much so that though they are still perceived, they are no longer painful.
Antacids are agents used to neutralize the excess acid in the stomach released in cases of acidity, gastritis and ulcers. They neutralize the effects of HCl, thereby providing relief from indigestion and heartburn. The efficacy of antacids depends on their capacity to protect the mucosa of the stomach from acid and pepsin. Drugs: Calcium carbonate.
Antiallergics prevent, inhibit, and alleviate allergic reactions. Generally, histamines are responsible for allergies. Antiallergics act as antihistamines and suppress their effects. Antiallergics act against itching and flash responses of the histamines. Antihistamines are subdivided in two broad categories: sedative and non-sedative. Cetirizine is one example of non-sedative antihistamine, while diphenhydramine and hydroxyzine are the examples of sedative antihistamines. Two lesser known categories of antihistamines are mast cell stabilizers and histamine receptor blockers.
Antianginals act against angina pectoris, that is the symptom exhibited in ischemic heart disease. Antianginals improve the balance between the delivery of oxygen to myocardium and its utilization by the myocardium. Antianginals are available in various forms, viz., calcium channel blockers, organic nitrates, beta-adrenergic blockers, potassium channel activators, and antiplatelet drugs. These drugs relieve angina pectoris by expanding blood vessels of the heart. Some are nitroglycerin, nifedipine, diltiazem, and verapamil.
Antiarrhythmic drugs are used to treat irregular heart rhythms resulting from the disturbance in the heart's electrical firing system. Antiarrhythmic drugs enhance the blood flow in the coronary vessels of the heart. This causes vasodilation and decreases the resistance felt in the peripheral vascular system. Clinically, antiarrhythmics are divided into three broad categories;
a) Which act on supraventricular arrhythmia (like digoxin and verapamil).
b) Which act on both supraventricular and ventricular arrhythmia (quinidine, amiodarone, metoprolol)
c) Which act solely on the ventricular arrhythmia.
Anticoagulants delay the clotting or coagulation process of blood. When any vessel is blocked by a clot of blood, an anticoagulant is administered to prevent new clots from forming with the earlier clots and thereby suppressing their enlargement. However, an anticoagulant only prevents from blood clotting but is incapable of dissolving an existing blood clot. Patients with artificial heart valves and atrial fibrillation are at the risk of forming blood clots and they are therefore prescribed anticoagulants to prevent such a situation. Heparin and warfarin are the most commonly used anticoagulants.
Anticonvulsants alleviate or reduce the severity of seizures and also prevent further seizure attacks.
Drugs useful in treatment of depression are termed as anti-depressants. There are three kinds of antidepressants, viz., tetracyclic, triazolopyridine, and tricyclic.
Antidiabetic agents are drugs that lower the blood sugar level. They are therefore also called hypoglycemic drugs. They are of two types; sulfonylureas and biguanides. Examples of sulfonylureas are chlorpropamide and glipizide while Metformin and phenformin are biguanides.
Antidiarrheals are the agents used to relieve diarrhea. They do so either by absorbing the excess fluids that cause diarrhea or by slowing the movement of fecal material through intestine thereby allowing more time for absorption of water. The first step in treatment of diarrhea is replacement of fluid and electrolytes.
Antiemetics are agents that suppress nausea and vomiting. These drugs act on brain control centers to stop nerve impulses, control motion sickness and dizziness. Antiemetics can be further divided into various categories like antihistamines, anticholinergics, and dopamine antagonists. Eg: Ondansetron is one of the strongest antiemetic.
Antiflatulents reduce gas and bloating. These agents facilitate passing out of gas by breaking down gas bubbles into smaller size by stimulating intestinal motility. Eg: Maalox, Mylanta.
Drugs that lower the intraocular pressure of the eyes by reducing production of aqueous humor are called antiglaucoma drugs. Most drugs of this class are beta-adrenergics. Drugs: timolol maleate, betaxolol, levobunolol, pilocarpine.
Histamines cause the swelling and inflammation of the nasal passages. Antihistamine counteracts that effect. Antihistamines are the primary agents used to relieve the allergic rhinitis symptoms. Antihistamines dry the respiratory tract and are effective in treating the cough caused by the allergens and the common cold in its early stages.
Antihypertensives are the agents used to lower high blood pressure. They include diuretics also known as water pills, beta blockers, alpha blockers, alpha-beta blockers, sympathetic nerve inhibitors, angiotensin converting enzyme inhibitors, and calcium channel blockers. Antihypertensives work one or more the following three ways to lower the blood pressures in the vessels, by decreasing the blood volume, restricting constriction or narrowing of the blood vessels and increase dilation thereby making the blood flow easier, by decreasing the force of the heart thereby decreasing the blood pumped through the arteries. Examples are amlodipine, quinapril, benazepril, captopril, clonidine, enalapril, furosemide, terazosin, lisinopril, nifedipine, and quinapril.
Are the drugs that reduce inflammation in cases of infection, injuries etc. Anti-inflammatory drugs are available in two types: steroidal and non-steroidal called NSAID. Anti-inflammatory drugs do not act directly against the causative agents. They act on the mechanisms of the body and reduce the inflammation. Non-steroidal anti-inflammatory drugs are generally used in cases of arthritis and gout. Glucocorticoids and aspirin are the examples.
Psoriasis refers to the circumscribed, silvery-scaled confluent, reddish lesions of the skin that primarily occur on knees, scalp, elbow, and trunk. Drugs treating psoriasis are called antipsoriatic drugs.
These drugs are effective for treatment of seborrheic dermatitis manifested by erythematous and scaly lesion. Selenium sulfide, selenium disulfide with clotrimazole, cetrimide, & a combination of cetyl alcohol, sulphur precipitate, salicylic acid. Indications: Dandruff, seborrheic dermatitis.
Antispasmodics are the agents used in prevention and reduction of smooth muscle spasms by acting on the autonomic nervous system, thus relieving spasms of bowel. Eg: Belladonna alkaloids.
Antitussive drugs suppress cough. Codeine, dextromethorphan are some examples.
Anti-ulcers are administered in the cases of peptic ulcers to get relief from pain, promote healing, and prevent recurrence. Drugs: ranitidine, cimetidine, omeprazole, famotidine, nizatidine.
Beta-adrenergic blocking agents are used in the treatment of arrhythmias, stable (exercise-induced) angina: unstable angina, postmyocardial hypertension, and migraine headaches. Beta-blockers act like inhibitors and interfere with the action of stimulating hormones on the beta-adrenergic receptors in the nervous system. Beta-blockers are divided into the groups of beta I (affecting the heart) and beta 2 (affecting the receptors in the bronchial tissue). Atenolol and metoprolol are the two examples of beta-adrenergic blockers.
Bronchodilators open up the clogged lung airway passages at times of airway narrowing. They open up the breathing passages and dilate the bronchi.
Calcium Channel Blockers
Calcium channel blockers are the agents that selectively block the flow of calcium ions into the cardiac and smooth muscle cells. These agents lower the blood pressure, relieve angina (chest pain), and stabilize the certain types of abnormal heart rhythms. They are used to treat angina pectoris, some form of hypertension, and some arrhythmias. Diltiazem and Verapamil are such calcium channel blockers.
Contraceptives inhibit ovulation and thereby acts as a deterrent against pregnancy. They are available as steroids and chemicals. Steroids are generally the oral contraceptive pills called OCP, a combination drug of estrogen and progesterone. On the other hand, chemical contraceptives comprise foam, gel, cream, or other spermicidals, which are placed in the vagina before intercourse. They prevent pregnancy by killing the sperms.
Corticosteroids are steroids produced by the adrenal cortex. Corticosteroids are used for adrenal insufficiency. They suppress inflammation, allergy, and reduce the chances of rejection in transplantation cases, and also treat some tumors. The two kinds of corticosteroids are mineralocorticoids and glucocorticoid. Aldosterone is an example of mineralocorticoids. Hydrocortisone, prednisolone, and triamcinolone are glucocorticoids.
Cycloplegics and Mydriatics
Cycloplegics are agents that paralyze ciliary muscles and result in pupillary dilation. Mydriatics are agents that cause dilation of pupils. Most of the mydriatics cause cycloplegia also. Drugs: atropine, homatropine, cyclopentolate, and tropicamide.
Decongestants reduce the congestion of swelling in the nasal passages, especially by constricting the blood vessels and limiting the blood supply to the area.
Diuretics increase the rate of urine formation after administration. All diuretic agents except osmotic diuretic act directly on the kidneys at the level of renal tubules. Diuretics are used to treat edema due to nephrotic syndrome and other diseases. Some examples are hydrochlorothiazide, Dyazide and Dyrenium.
Emollients and Keratolytics
Emollients are agents used to soothe and hydrate the skin. After application on the skin, emollients prevent evaporation of water by forming a thin greasy layer on the skin surface. Emollients improve the dryness of skin but are not to be used on exudative lesions, Vaseline petrolatum, oils like coconut, ground nut, etc. Keratolytics are agents applied to soften the epidermic cells and desquamate them. Salicylic acid, benzoic acid, propylene glycol, zinc oxide, and dimethicone are some of them.
Estrogen hormones are used as oral contraceptives and also in the treatment of postmenopausal osteoporosis. They act by binding the estrogen nuclear receptors. However, prolonged use can lead to skin rash, thromboembolism, and endometrial cancer. Estrogens are secreted by ovaries and are necessary for normal development of breasts, female genital tract, and secondary sexual characteristics. Estrogens are also necessary for maintenance of pregnancy:
They help loosen the mucus by making bronchial secretions thinner and easier to cough up. Iodides are commonly used expectorants, and guaifenesin and terpin hydrate are ingredients in many over-the-counter preparations.
Fibrin is a kind of elastic protein derived from fibrinogen, which helps in the clotting of blood. Fibrinolytics dissolve the clots by hydrolysis of fibrin. These fibrinolytics produce plasmin enzyme, which acts against the clotting process. Fibrinolytics are used in the treatment of pulmonary embolism and deep venous thrombosis.
Gonadotropins are the hormonal preparations of follicle stimulating hormone (FSH) and luteinizing hormone (LH) that raise the sperm count in infertility cases. These preparations are required for ovulation and spermatogenesis.
Hemostasis is a condition in which bleeding is arrested and hemostatics are agents, which arrest the bleeding in the vessels.
Hypnotics are those agents or drugs, which have soporific effect and are used for causing sleep or hypnosis.
Immunosuppressants prevent or interfere with the immunologic response. In cases of transplants, the host tissues sometimes reject the transplanted organs or tissues. Immunosuppressants are used to facilitate the acceptance of the transplanted organs and prevent the rejection and also used in the treatment of autoimmune disease.
Laxatives promote bowel movements and defecation when used in small doses to relieve constipation and in large doses to evacuate the whole gastrointestinal tract. Drugs: cascara sagrada, casanthranol, and docusate.
Miotic agents cause constriction of pupil of eye. Mostly used in the treatment of glaucoma. These agents are used to counteract mydriatics after they have been used for testing refraction. Drugs: pilocarpine.
Mucolytics liquefy or break down the obstinate mucus so that it can be expectorated more easily.
Muscle relaxants are those agents, which reduce the muscle tension and provide therapeutic treatment. These agents block the polysynaptic spinal reflexes and reduce the muscle tone. Examples: Baclofen, methocarbamol, and tizanidine.
Neuromuscular drugs are generally used during anesthesia administration to allow access to body cavities. They prevent the voluntary or reflex muscle movement interference. Neuromuscular drugs can be divided into three broad categories: non-depolarizing muscle relaxants, depolarizing neuromuscular blockers, and anticholinesterases used in anesthesia.
Various antibiotics are used in many eye infections caused by pathogens like bacteria. Many of these antibiotics are used in combination with corticosteroids. These antibiotics are used to treat bacterial infections of the eye, fungal infections of the eye, conjunctivitis, keratitis, blepharitis, meibomianitis, trachoma, dacryocystitis and differ according to the type of infection. Drugs: norfloxacin, ciprofloxacin, gentamicin, tobramycin, sulfacetamide sodium, chloramphenicol, miconazole, silver sulfadiazine, acyclovir, ofloxacin, framycetin sulfate, polymyxin.
Opiates are the narcotic drugs derived from opium. There are multifarious uses of opiates. They are used as analgesics, hypnotics, mood elevators, and antidiarrheals.
Oxytocin is a nonapeptide neurohypophyseal hormone that causes myometrial contractions at term and promotes milk release during lactation. Oxytocins are used for induction or stimulation of labor. They are also used to manage the postpartum hemorrhage and atony
Psychotropic drugs affect the mind, emotions, and behavior. They are used in the treatment of psychic illnesses.
Sedatives are those agents or drugs that depresses the central nervous activities and contain the excitement.
Spermicidals are available in gel, pessary or foam, or in cream formulation. (Pessary is a surgical plug worn in the vagina to support the womb.) Spermicidals are placed in the vagina for contraception, for they destroy the sperms.
Topical analgesics stimulate the sensory nerve endings and produce a soothing tingling sensation and warmth. Diclofenac, nimesulide, and ketoprofen are the examples of such topical analgesics.
Topical antifungals kill the fungus selectively. These include scabicides, which kill the scabiei that invade the epidermis. Examples: malathion, lindane, benzyl benzoate. Some other antifungals are miconazole, which has a broad spectrum of antifungal activity and is used for fungal and eczematous infections of tinea, candidiasis of skin and nails and also for eczema with bacterial infection; clotrimazole, which is used for tinea infections, fungal nappy rash, candida vulvitis, candida balanitis, paronychia, and athlete’s foot; econazole for fungal infections of skin and skin infections due to gram positive bacteria; and ketoconazole for fungal infections of skin.
Topical anti-infectives are used for treatment of bacterial infections of skin, impetigo, eczema, folliculitis, leg ulcers. Also used for abrasions, cuts, and as preoperative antiseptics. Examples-mupirocin, tetracycline, aminoglycoside, sulfonamides, nitrofurazone, acyclovir. The antiseptics used are chloroxylenol, cetrimide, Povidone iodine.
Topical steroids are used to treat various dermatological disorders like contact dermatitis, psoriasis, keloid scars, seborrheic dermatitis, eczema, and vulval pruritus. Examples: beclomethasone dipropionate, triamcinolone acetate, hydrocortisone, methyl prednisolone acetate, dexamethasone sodium phosphate.
Tranquilizers are agents or drugs, which have a calming, soothing, or pacifying effect. This helps in the treatment of anxiety and agitation.
Uricosurics increase the excretion of uric acid from the body They are generally used to treat gout. Some of the prominent uricosurics used are allopurinol (Zyloprim), colchicine (available as generic only), probenecid (Probalan), etc.
Vaccines and immunoglobulins
Vaccines and immunoglobulins are used for immunological prophylaxis. Immunization can be obtained in two ways, active and passive. Active immunization is obtained through the administration of vaccines and also by recovering from an infection and thereby building the resistance. Passive immunization is obtained through the administration of antibodies by means of antiserum and immunoglobulins. Some of the well-known vaccines and immunoglobulins are as follows: BCG vaccines, polio vaccines, triple antigen, tetanus immunoglobulin, rabies immunoglobulin, etc.
Antiseptics and Disinfectants
Proflavine, Benzalkonium chloride, cetrimide, Formaldehyde solution, Hexachlorophene, Liquefied phenol, Nitrofurantoin. Sulfathiazole, succinyl sulfathiazole, sulfadimethoxine, sulfamethoxypyridazine. Sulfa, co-trimoxazole, sulfacetamide.
Some Common Drugs:
· Antileprotic Drugs-clofazimine, Thiambutosine, Dapsone, solapsone.
· Anti-tubercular Drugs-Isoniazid, PAS, Streptomycin, Rifampicin, Ethambutol, Thiacetazone, Ethionamide, Cycloserine, Pyrazinamide.
· Anti-amoebic and /anthelmintic Drugs-Emetine, Metronidazole, Halogenated hydroxyquinoline, diloxanide furoate, Paromomycin Piperazine, Mebendazole.
· Antibiotics-Benzyl Penicillin, Phenoxy methyl Penicillin &, Benzathine Penicillin, Ampicillin, Cloxacillin, Carbenicillin, gentamicin, Neomycin, Erythromycin, Tetracycline, Cephalexin, Cephaloridine, Cephalothin, Griseofulvin, Chloramphenicol. Antifungal agents-Undecylenic acid, Tolnaftate, Nystatin, Amphotericin, Hamycin.
· Antimalarial Drugs-Chloroquine, Amodiaquine, Primaquine, Proguanil, Pyrimethamine, Quinine, Trimethoprim.
· Tranquilizers-Chlorpromazine, Prochlorperazine, Trifluoperazine, Haloperidol, Oxypertine, Chlordiazepoxide, Diazepam, Lorazepam, Meprobamate.
· Hypnotics:- Phenobarbitone, Methyprylon, paraldehyde. Triclofos sodium.
· General Anesthetics-Halothane, Cyclopropane, Diethyl ether, Methohexital sodium, Thiopental sodium, Trichloroethylene.
· Antidepressant Drugs-Amitriptyline, Nortriptyline, imipramine, Phenerzine, Tranylcypromine.
· Analeptics-Theophylline, Caffeine, Dextro-amphetamine.
· Adrenergic Drugs-Adrenaline, Noradrenaline, Isoprenaline, Phenylephrine, Salbutamol, Terbutaline, Ephedrine, Pseudo ephedrine.
· Adrenergic Antagonist-Tolazoline, Propranolol.
· Cholinergic Drugs-Neostigmine, Pyridostigmine, Pralidoxime, Pilocarpine, Physostigmine.
· Cholinergic Antagonists-Atropine, Hyoscine, Homatropine, Propantheline, Benztropine, Tropicamide, Biperiden *.
· Diuretic Drugs-Furosemide, Chlorothiazide, Hydrochlorothiazide Benzthiazide, Urea, Mannitol, Ethacrynic Acid.
· Cardiovascular Drugs-Ethyl nitrite, Glyceryl trinitrate, Alpha methyldopa, Guanethidine, Clofibrate, Quinidine.
· Hypoglycemic Agents-Insulin, chlorpropamide, Tolbutamide Glibenclamide, Phenformin, Metformin.
· Coagulants and Anti Coagulants-Heparin, Thrombin, Menadione, Bishydroxycoumarin, Warfarin Sodium.
· Local Anesthetics-Lignocaine, Procaine, Benzocaine.
· Histamine and Anti histaminic Agents-Histamine, Diphen Hydramine. Promethazine, Cyproheptadine, Mepyramine, Pheniramine, Chlorpheniramine.
· Non-steroidal anti-inflammatory Agents-Indomethacin, Phenylbutazone, Oxyphenbutazone, Ibuprofen.
· Antithyroids-Thyroxine, Methimazole, Methyl thiouracil, Propylthiouracil.
· Diagnostic Agents-Iopanoic Acid, Propyliodone, Sulfobromophthalein Sodium, Indigotindisulfonate Sodium (Indigo Carmine), Evans blue, Congo Red, Fluorescein Sodium.
· Steroidal Drugs-Betamethasone, Cortisone, Hydrocortisone, prednisolone, Progesterone, Testosterone, Oestradiol Nandrolone.
· Anti-Neoplastic Drugs-Actinomycins, Azathioprine, Busulfan, Chlorambucil, Cisplatin cyclophosphamide, Daunorubicin, Hydrochloride, Fluorouracil, Mercaptopurine, Methotrexate.
A medical prescription is an order usually in written form by a qualified health care professional or other therapist for the treatment to be provided to their patient. Prescriptions are typically handwritten on preprinted prescription forms, or may alternatively be using computer these days. The prescription should contain the name and address of the prescribing doctor and any other legal requirement such as registration number of the physician. What is unique for each prescription is the name of the patient, date, the details of the medication and the directions for taking them. Last but not the least the prescription should be appropriately signed by the physician prescribing it.
The symbol "Rx" meaning "prescription" is a transliteration of a symbol. There are various theories as to the origin of this symbol but in literal terms, "Rx" indicates an instruction "to take" what is specified in the prescription. The word "prescription" can also be decomposed into "pre" and "script" and in literal terms means, "to write before" a drug can be prepared.
Who Can Write Prescriptions?
In the United States, physicians, veterinarians, dentists, and podiatrists can issue prescriptions. Some states may allow optometrists to issue eyeglass prescriptions for corrective eyeglasses though technically these cannot be termed as medical prescriptions. Even nurse practitioners, physician assistants, optometrists, homeopathic physicians, registered pharmacists, and doctors of some other branches of medicine do have the authority to prescribe.
Non-Prescription Drug Prescriptions
Prescriptions are also used for things that are not strictly regulated as a prescription drug. Doctors will often give non-prescription drugs out as prescriptions because drug benefit plans may reimburse the patient only if the over-the-counter medication is taken under the direction of a doctor. Conversely, if a medication is available over-the-counter, doctors may ask patients if they want it as a prescription and possibly incur a pharmacist's dispensing fee or whether they want to get it themselves at a lower price. If the patient wants the medication not under prescription, the doctor is usually careful to give the medication name to the patient on a blank piece of paper to avoid any confusion with a prescription.
Over-the-counter or OTC substances are drugs and other medical remedies that may be sold without a prescription and without a visit to a medical professional, in contrast to prescription only medicines (POM). As a general rule, over-the-counter drugs have to be primarily used to treat a condition that does not require the direct supervision of a doctor and must be proven to be reasonably safe and well tolerated with little abuse potential.
Requirements on Information
Every person who dispenses a drug pursuant to a prescription shall ensure that the following information is recorded on the prescription,
(a) the name and address of the person for whom the drug is prescribed;
(b) the name, strength (where applicable) and quantity of the prescribed drug;
(c) the directions for use, as prescribed;
(d) the name and address of the prescriber;
(e) the identity of the manufacturer of the drug dispensed;
(f) an identification number or other designation;
(g) the signature of the person dispensing the drug and, where different, also the signature of the person receiving a verbal prescription;
(h) the date on which the drug is dispensed;
(i) the price charged. R.S.O. 1990, c. H.4, s. 156 (1).
List of Prescription Abbreviations
This is a list of all abbreviations used in prescriptions. Capitalization and the use of a period is a matter of style. In the attached list, Latin is not capitalized whereas English acronyms are. The period is used wherever there are letters omitted in the abbreviation.
aa (ana) - of each
ad - to, up to
a.c. (ante cibum) - before meals
a.d. (aurio dextra) - right ear
ad lib. (ad libitum) - use as much as one desires; freely
admov. (admove) - apply
agit (agita) - stir/shake
alt. h. (alternis horis) - every other hour
a.m. (ante meridiem) - morning, before noon
amp - ampule
amt - amount
aq (aqua) - water
a.l., a.s. (aurio laeva, aurio sinister) - left ear
A.T.C. - around the clock
a.u. (auris utrae) - both ears
bis (bis) - twice
b.i.d. (bis in die) - twice daily
B.M. - bowel movement
bol. (bolus) - a large pill
B.S. - blood sugar
B.S.A - body surface areas
cap., caps. (capsula) - capsule
c (cum) - with (usually written with a bar on top of the "c")
c (cibos) - food
cc - cubic centimeter; also means "with food" (cum cibos)
cf - with food
D5W - dextrose 5% solution (sometimes written as D5W)
D5NS - dextrose 5% in normal saline (0.9%)
D.A.W. - dispense as written
dc, D/C, disc - discontinue
dieb. alt. (diebus alternis) - every other day
dil. - dilute
disp. - dispense
div. - divide
d.t.d. (dentur tales doses) - give of such doses
D.W. - distilled water
elix. - elixir
e.m.p. (ex modo prescripto) - as directed
emuls. (emulsum) - emulsion
et - and
ex aq - in water
fl., fld. - fluid
ft. (fiat) - make; let it be made
g - gram
GI - gastrointestinal
gr - grain
gtt(s) (gutta(e)) - drop(s)
GU - genitourinary
H - hypodermic
h, hr - hour
h.s. (hora somni) - at bedtime
ID - intradermal
IM - intramuscular (with respect to injections)
inj. (injectio) - injection
IP - intraperitoneal
IV - intravenous
IVP - intravenous push
IVPB - intravenous piggyback
L.A.S. - label as such
LCD - coal tar solution
lin (linimentum) - liniment
liq (liquor) - solution
lot. - lotion
M. (misce) - mix
m, min (minimum) - a minimum
mcg - microgram
mEq - milliequivalent
mg - milligram
mist. (mistura) - mix
mitte (mitte) - send
mL - millilitre
N&V, N/V - nausea and vomiting
nebul (nebula) - a spray
NKA. - no known allergies
NKDA - no known drug allergies
non rep. (non repetatur) - no repeats
NPO, n.p.o. (nil per os) - nothing by mouth
NS - normal saline (0.9%)
1/2NS - half normal saline (0.45%)
N.T.E. - not to exceed
o.d. (oculus dexter) - right eye
o.s. (oculus sinister) - left eye
o.u. (oculo utro) - both eyes
oz - ounce
per - by or through
p.c. (post cibum) - after meals
p.m. (post meridiem) - evening or afternoon
prn (pro re nata) - as needed
p.o. (per os) - by mouth or orally
p.r. - by rectum
pulv. (pulvis) - powder
q (quaque) - every
q.a.d. (quoque alternis die) - every other day
q.h. (quaque hora) - every hour
q.1h (quaque 1 hora) - every 1 hour; (can replace "1" with other numbers)
q.d. (quaque die) - every day
q.i.d. (quater in die) - four times a day
q.o.d. - every other day
q.s. (quantum sufficiat) - a sufficient quantity
R - rectal
rep., rept. (repetatur) - repeats
RL, R/L - Ringer's lactate
s (sine) - without (usually written with a bar on top of the "s")
s.a. (secundum artum) - use your judgment
SC, subc, subq, subcut - subcutaneous
sig - write on label
SL - sublingually, under the tongue
sol (solutio) - solution
s.o.s., si op. sit (si opus sit) - if there is a need
ss (semis) - one half
stat (statim) - immediately
supp (suppositorium) - suppository
susp - suspension
syr (syrupus) - syrup
tab (tabella) - tablet
tal., t (talus) - such
tbsp - tablespoon
troche (trochiscus) - lozenge
tsp - teaspoon
t.i.d. (ter in die) - three times a day
t.i.w. - three times a week
top. - topical
TPN - total parenteral nutrition
tr, tinc., tinct. - tincture
u.d., ut. dict. (ut dictum) - as directed
ung. (unguentum) - ointment
USP - United States Pharmacopoeia
vag - vaginally
w/o - without
X - times
To avoid ambiguity, the following abbreviations are not recommended:
· a.u., a.d., a.s. - Latin for both, left and right ears; the "a" can be misread to be an "o" and interpreted to mean both, right or left eyes
· d/c - can mean "discontinue" or "discharge"
· h.s. - can mean half strength or "hour of sleep"
· q.o.d. - meant "every other day" but the "o" can be interpreted as "." or "i" resulting in double or eight times the frequency
· SC/SQ - meant "subcutaneous" but mistaken for "SL" for "sublingual"
· TIW - meant 3 times a week but mistaken for twice a week
· U - meant "units" but mistaken for "0", "4" or "cc" when poorly written; conversely cc can be mistaken for "U"
· μg - meant "microgram" but mistaken for "mg"; this 1000-fold error can cause potentially fatal misunderstandings.
Pharmacology & Drug Classifications