TDM (Therapeutic Drug Monitoring) is done for all of the following except:: (A) Theophylline, (B) Lithium, (C) Metformin, (D) Phenytoin
Answer is C. TDM is done for drugs which have narrow therapeutic index or in cases where effect of drugs cannot be measured clinically. Metformin is a antidiabetic drug whose effect can be monitored using blood sugar levels.