A pharmaceutical drug, also referred to as medicine or medicament, can be loosely defined as any substance intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease. Other synonyms include pharmacotherapy, pharmacotherapeutics, and drug treatment.

Classification

Medications can be classified in various ways, such as by chemical properties, mode of administration, biological system affected, or therapeutic effects. An elaborate and widely used classification system is the Anatomical Therapeutic Chemical Classification System (ATC system). The World Health Organization keeps a list of essential medicines.

A sampling of classes of medicine includes:

1. Antipyretics: reducing fever (pyrexia/pyresis)
2. Analgesics: painkillers
3. Antimalarial drugs: treating malaria
4. Antibiotics: inhibiting germ growth
5. Antiseptics: prevention of germ growth near burns, cuts and wounds

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 or beta 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, haemostatic drugs
• Atherosclerosis/cholesterol agents: hypolipidaemic agents, statins.

For the central nervous system

hypnotic, anaesthetics, 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 musculo-skeletal disorders

NSAIDs (including COX-2 selective inhibitors), muscle relaxant, neuromuscular drug
anticholinesterase

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-viral:
• 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