<prompt> Which of the following drug require therapeutic dose monitoring?PhenytoinWarfarinMetforminPropanolol  <response>: Ref: Katzung, 14th ed. pg. 432; KDT, 6th ed. pg. 34-35Therapeutic dose monitoring TDM is used to monitor the effect of drug through plasma concentration.Criteria to do TDMWhen response of drug cant be measured.Note:Response of warfarin measured by INR.Response of metformin measured by blood glucose level.Response of propanolol measured by BP measurement.If any drug having narrow therapeutic index unsafe drugs.If a drug is showing wide variation in pharmacokinetics.Drugs in which TDM done Remembered as: DAAALIDigitalisAminoglycosides GentamicinAnti-epilepticsAnti-CancerLithiumImmuno suppressant Cyclosporine, Tacrolimus, SirolimusTherapeutic drug range for some anti-seizure drugDrugReference rangeCarbamazepine4-12Clobazam0.03-0.30Ethosuximide40-100Phenytoin10-20Phenobarbital15-40Valproate40-100Lamotrigine3-15Levetiracetam12-46Oxcarbazepine5-35Topiramate5-20 