Which of the following drug shows "Therapeutic window" phenomenon-

Ans. is 'a' i.e., Carbamazepine Therapeutic window The term therapeutic window refers to the range of doses of a drug that are actually effective in treating a paicular disease. It is the range of dosage that can effectively treat a condition while still remaining safe, i.e. therapeutic window is the range between the lowest dose that has a positive effect and the highest dose before the negative effects outweigh the positive effect. Doses below the therapeutic window are too weak to have any effect and doses above the window cause unacceptable side effects. o In a literal sense, therapeutic window is same as therapeutic range. o So, every drug will have a therapeutic window, i.e. the range of dose or plasma concentration below which the drug is ineffective and above which the drug causes unacceptable side effects. But, in general the drugs which have narrow therapeutic window (narrow therapeutic range) are considered to show therapeutic window phenomenon. o These drugs have already been listed in previous explanations. Drugs are i) Antiepileptics --> Phenytoin, carhamazepine, Lignocaine v) Lithium ii) Tricyclin antidepressants -- imipraminc vi) Aminoglycosides iii) Theophylline vii) Digoxin iv) Cyclosporine Note : According to KDT answer is 'd' i.e., clonidine: Read below Therapeutic window phenomenon Optimal therapeutic effect is exeed only over a narrow range of plasma drug concentration or drug doses; both above and below this range, beneficial effects are suboptimal ie. the effect declines if the doses arc increased beyond a ceain level. Examples are : Tricyclic antidepressants (imipramine), Clonidine, Glipizide o But, I am in our of Goodman & Gilman, because I have done extensive search on that, all other standard text books and various aicles have mentioned the same as Goodman & Gilman. o You are free to choose your ourite.