Quinidine

Quinidine is the dextro-diastereomer (optically active stereo-isomer) of quinine. It has the same anti-malaria properties, but has a more pronounced action on the myocardium. With quinidine there is a narrower margin between the therapeutic and toxic plasma levels. It is used as an anti-arrhythmic agent (e.g. Quinidine durette 250 mg tablet). In emergencies it can be used for malaria treatment. The dosage is the same as that for quinine. A loading dose may be given. N.B.: 10 mg quinidine gluconate = 6.25 mg quinidine base.

Anecdote:

Unlike the majority of other bitter products which occur naturally, the bitter taste of quinine is short-acting with no annoying after-taste. It is therefore used as a flavouring to produce tonic water. The British colonialists in India often drank gin and tonic. The present-day tonic water contains approximately 15 mg per litre, however, only enough to give a bitter taste. Copious drinking of gin and tonic in order to prevent malaria, is thus only an excuse for drinking gin.

Category: Medicine Notes