Class of Drug Intended Action
 Prophylactic  Prevent disease rather than treat it afterwards.
 Analgesic Reduce or eliminate pain. (See Yellow Corydalis and Opium Poppy)
 Sedatives To sedate or calm. (See Common Valerian)
 Antibiotic Eliminate a bacterial infection.
 Antispasmodic Reduce muscle twitches / cramp.
 Antacids Neutralise excess acid in the stomach.
 PPI (Proton Pump Inhibitor) Prevent excess stomach acid.
 Cytoprotectant Protects against stomach ulcers by increasing mucosal lining rather than reducing stomach acid.
 Laxative Relieve constipation.
 Antiflatulent Reduce wind.
 Antidiarrhoeals Prevent diarrhoea.
 Cardiac Glycosides Slow the rhythm and increase the force of the heart (See Foxglove and Lily-of-the-Valley)
 Antiarhythmic Treat abnormal heart rhythms.
 Antianginals Treat angina, a dangerous and painful condition of the heart muscles caused by lack of sufficient oxygen getting to them.
 Vasoconstrictor Constrict blood vessels
 Vasodilator Dilate blood vessels.
 ACE Inhibitor
(Angiotensin-Converting Enzyme Inhibitor)
 Block the action of a hormone produced by the kidneys and which constricts blood-vessels.
 Alpha Blockers Block the peripheral actions of catecholamines, e.g. on blood vessels and the bladder
 Beta Blockers Blocks the central actions of catecholamines, e.g. on the heart and lungs
 Diuretic Induce Urination
 Anticoagulant Reduce ability of blood to clot
 Antiplatelet Reduce the stickiness of blood platelet cells.
 Fibrinolytic 'Clot busters' for Deep Vein Thrombosis, etc.
 Statins / Hypolipidaemics Reduce blood cholesterol.
 Hypnotic Induce Sleep.
 Local Anaesthetic Relieve pain locally during an operation
 General Anaesthetic Induce unconsciousness for an operation
 Antipsychotic Treat Psychosis
 Anti-depressant Treat Depression
 MAO Inhibitor Prevent breakdown of brain catecholamines; this can treat depression. Very powerful drugs, with powerful side-effects and interactions.
 Acetylcholine Esterase Inhibitor (A specific MAO Inhibitor). Prevents breakdown of acetylcholine. Treats Alzheimers and other memory problems. (See Snowdrop)
 Cholinergic Increases the activity of acetylcholine at nerve-endings
 Anticholinergic Decreases the activity of acetylcholine at nerve-endings
 Anticholinesterase Prevents breakdown of acetylcholine at nerve endings
 SSRI Selective Serotonin Re-uptake Inhibitors, used as anti-depressants. (Serotonin is another monoamine)
 5-HT antagonist Specialised anti-emetics treating nausea and vomiting
 Antidopaminergic Blocks the action of dopamine
 Anti-emetic Stop stomach purging.
 Anti-convulsant Stop involuntary and repeated flexure of limbs, e.g. during an epileptic fit.
 Anti-epileptic Counteracts epilepsy
 Anxiolytic Reduce anxiety.
 Barbiturate Depress the Central Nervous System.
 Stimulant Stimulate the Central Nervous System
 Antihistamine Reduce inflammation caused by an external irritant, e.g. wasp sting, pollen allergy.
 Emetic Induce vomiting.
 Bronchodilator Relieve spasm in bronchioles during an asthma attack. (See Yellow Horned-Poppy)
 Mydriatic To dilate the pupil of the eye. (See Henbane)
 Antitussive Suppress and relieve coughs.
 Mucolytic Loosen mucous from lungs and air-passages.
 Decongestant Relieve nasal congestion.
 Anti-diabetic Reduce the blood-glucose level in the treatment of diabetes. (See Goat's-Rue)
 Antipruritic Reduce itching
 Ascaricide Treat worm infestations
 Antimalarial Counteract Malaria
 Anthelmintic Treat internal worms (See Agrimony)
 Antiprotozoal Treat a protozoal infection.
 Amoebicide Treat an amoebal infestation.
 Taeniacide Treat for worm infection.
 Antifungal Treat a fungal infection.
 Antiviral / Virucidal Prevents replication of virii within a mammal.
 Vaccine Provide protection from a particular virus, usually before but can be after infection. Increases immunity to that virus.
 Antitoxins Neutralise, counter or sequester ingested poisons.
 Sudorific Induce sweating.
 Antipyretic Reduce elevated body temperature.
 Anti-inflammatory Reduces or prevents inflammation of the skin or membranes. (See Horse-Chestnut)
 NSAID [Non-steroidal anti-inflammatory drug] - reduce inflammation. (See Meadowsweet)
(a Histone DeAcetylase)
 Prevents progression into shock following large loss of blood. (See Common Valerian)
 Anorexiant Reduces body weight.


There are innumerable different drugs associated with each Class of Drug, some more effective than others, and others very much more expensive, but certainly not necessarily more effective. With drugs especially, you don't get what you pay for: those still useful drugs that are out of patent (so called 'generic' drugs) can be much cheaper than newer and not necessarily more effective drugs that are still within patent.

It should be remembered that most drugs have un-intended side effects. The side effects can vary even within the same class of drugs.

However, there are some drugs whose side effects are un-avoidable. For instance, an anti-coagulant, which reduces the ability of the blood to clot (thereby avoiding errant and dangerous clotting within the blood vessels themselves) will automatically increase the propensity for un-intended, but unavoidable, internal bleeding, which can be just as dangerous. Normally, internal bleeding from capillaries happens all the time, but the consequences are usually benign, for once escaped, the platelets coagulate externally from the capillaries to block any further flow. If the ability of the blood to clot is removed (by administering an anti-coagulant) then this process is prevented from occurring, resulting in potentially fatal internal bleeding.

The dose of any drug needs to be carefully controlled and the effects monitored to try to reduce the severity of un-intended side effects such as these.

Side effects like the one described above can be designed out. If, instead of reducing the ability of the blood to clot, a drug was found that reduces the ability of platelets to stick to the internal walls of (un-broken) blood vessels, but does not affect its ability to clot (conglomerate together) once outside those blood vessel, then this would circumvent this particular side effect. Such drugs may, or may not, be available in this particular circumstance, but that is by the by; the intention was to show how, by re-designing the action of a drug, otherwise seemingly un-avoidable side effects can be circumvented. But that is not to say that the new drug would be without other unpredicted and undesirable side-effects. Such is the complexity of multi-cellular organisms like ourselves all with unique (to ourselves) genomes.

Then there is the variability between humans allured to directly above; we are not all the same! One drug may work well in one person, but poison another.


The data sheets supplied with most drugs, if anyone cared to read them, usually list as a side effect the very symptoms that the drug is meant to treat! This is not (usually) to say that the drug can cause this disease in totally fit people who shouldn't be taking the drug in the first place, but rather as an expedient way of saying that the drug might not work for you, in which case you would have the same symptoms as you started with, and which, being un-treated, may well be getting worse...


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