General Knowledge

Chemical used in Medicine

Chemical used in Medicine


Drugs are the chemicals of low molecular masses. These interact with macromolecular targets and produce a biological response. When biological response is useful, these chemicals are called medicines. These are used in diagnosis, prevention, and treatment of diseases.

Analgesics (Pain Relievers)

These reduce pain without causing disturbance in nervous system.

These are of two types :
non-narcotic analgesic
narcotic analgesic

» Aspirin and paracetamol are non-narcotic analgesics.
» Narcotic analgesics are morphine, heroin, and codeine.


These are used for treatment of stress and mild or even severe mental diseases. They form an essential component of sleeping pills.

Different types of tranquilizers function by different mechanisms.
Anti-depressant drugs — e.g., Iproniazid and phenelzine, Chlordiaz- epoxide and meprobamate are mild tranquilizers and used for relieving tensions.
Equanilis — used in controlling depression and hypertension.
Hypnotic (sleep producing agents) — Derivatives of barbituric acid such as luminal, and amytal are known as barbiturates.


» These drugs are generally administered by an anaesthesia provider in order to reduce or maintain general anaesthesia (reversible loss of consciousness) to facilitate surgery.

» These are given as gases (or vapours) or by injections (intravenous desflurane, isoflurane and sevoflurane are the most widely used volatile anaesthetics today). These are combined with nitrous oxide.

» Anaesthetists prefer to use intravenous injections as they are faster. The most widely used drugs are propofol, etomidate, barbiturates, benzodiazepine, etc.


These drugs are used to treat infections. Initially, these are produced from microorganisms. These have either killing effect (cidal effect) or inhibitory effect (static effect) on microbes. Some commonly used antibiotics are sulphanilamide, sulphapyridine, penicillin, chloramphenicol, vancomycin, ofloxacin, and dysidazirine.

Antiseptics and Disinfectants

These are the chemicals that either kill or prevent the growth of microorganisms. Antiseptics are applied to living tissues, while disinfectants are applied to inanimate objects such as floors and instruments.

Some examples of antiseptics are :
• Dettol is a commonly used antiseptic. It is a mixture of chloroxylenol and terpineol.
• Bithionol is added to soap due to its antiseptic properties.
• Tincture of iodine 2-3% solution of I, in alcohol-water mixture.
• Boric acid in dilute aqueous solutions is used as an antiseptic for eyes.

Some examples of disinfectants :
• 1% solution of phenol,
• 0.2 to 0.4 ppm of chlorine in aqueous solution (disinfectant for drinking water), and
• sulphur dioxide (SO2) in very low concentration (preservation of squashes)


They remove the excess acid and raise the pH to an appropriate level in the stomach. Sodium hydrogen carbonate, a mixture of aluminium and magnesium hydroxide (gel), is used as an antacid. However, excessive use of sodium bicarbonate (NaHCO3) makes the stomach alkaline and triggers the production of even more acid.