This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pharmacokinetics, Subject name: Pharmacology
Which drug is not acetylated? 
Select and explain. 
A. INH, B. Dapsone, C. Hydralazine, D. Metoclopropamide
D: Metoclopropamide
Answer: D: Metoclopropamide 
Explanation: Ans. is 'd' i.e. Metoclopramide Acetylation is a phase II metabolic reactionPhase II reactions serves to attach a conjugate to the drug molecule. After the phase II reactions all drugs becomes water soluble, so that they can be readily eliminated from the body.Phase II reactions includesGlucuronidationAcetylationMethylationSulfationGlycine conjugation AcetylationDrugs having amino or hydrazine resides are conjugated with the help of acetyl coenzyme A. Examples are :S - Sulfonamides (Dapsone)H- Hydralazine I - Isoniazid P-PASAcetylation is a genetically mediated condition.Multiple genes control the acetyl transferases and the rate of acetylation shows genetic polymorphism