What are analgesics? How are they classified? Give examples.

Analgesics are a class of drugs that reduce or abolish pain without causing impairment of consciousness, mental confusion, incoordination or paralysis or some other disturbances of nervous system. Analgesics are classified as: (i) Non-narcotic (non-addictive) analgesics: Aspirin and paracetamol belong to the class of non-narcotic analgesics. Aspirin is the most familiar example. Aspirin inhibits the synthesis of chemicals known as prostaglandins which stimulate inflammation in the tissue and cause pain. These drugs are effective in relieving skeletal pain such as that due to arthritis. These drugs have many other effects such as reducing fever (antipyretic) and preventing platelet coagulation. Because of its anti blood clotting action, aspirin finds use in prevention of heart attacks. (ii) Narcotic drugs: Morphine and many of its homologues are narcotic analgesics, when administered in medicinal doses it relieves pain and produce sleep. Over dosage of these produce stupor, coma, convulsions and ultimately death. Morphine narcotics are sometimes referred to as opiates. These analgesics are chiefly used for the relief of postoperative pain, cardiac pain and pains of terminal cancer, and in child birth.

What are artificial sweetening agents? Give example.

Artificial sweetening agents are chemical substances that used for sweetening food without adding any calories, unlike natural sweeteners. So, they do not harm the human body. It is around 550 times sweet as cane sugar. It gets excreted from the body in the urine unchanged. Hence, these are helpful for people suffering from diabetes. Some examples of artificial sweeteners are aspartame, saccharin, and alitame.

What are the main constituents of dettol?

Dettol is an antiseptic. The main constituents of dettol are chloroxylenol and α -terpineol. It is a mixture or combination of chloroxylenol and terpineol in a suitable solvent.

What are antiseptics? Give example.

Antiseptics are chemicals applied to the living tissues such as wounds, cuts, ulcers and diseased skin surfaces to prevent the growth of microorganisms. These are not ingested like antibiotics. Commonly used antiseptic, dettol is a mixture of chloroxylenol and terpineol. Iodine is a powerful antiseptic. Its 2 - 3 per cent solution in alcohol water mixture is known as tincture of iodine. It is applied on wounds.

What are antacids? Give examples.

Over production of acids in stomach causes irritation and pain. Antacids are taken to reduce acidity. A major breakthrough in the treatment of hyperacidity came through the discovery according to which a chemical, histamine, stimulates the secretion of pepsin and hydrochloric acid in the stomach. The drug cimetidine, was designed to prevent the interaction of histamine with the receptors present in the stomach wall. This resulted in release of lesser amount of acid. Histamine, Cimetidine, Ranitidine are examples of antacids.

What is allosteric site?

Some drugs do not bind to the enzyme’s active site. These bind to a different site of enzyme which is called allosteric site. This binding of inhibitor at allosteric site changes the shape of the active site in such a way that substrate can not recognise it.