This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pharmacodynamics, Subject name: Pharmacology
Which of the following drug is not metabolized by acetylation? 
Select and explain. 
A. Isoniazid, B. Hydralazine, C. Phenytoin, D. Procainamide
C: Phenytoin
Answer: C: Phenytoin 
Explanation: Metabolism by acetylation: Two types of individuals are found, slow and fast acetylators. -Acetylation is done by N acetyl transferase enzyme. Drugs metabolised by acetylation *Sulfonamide* Hydralazine* Isoniazid* Procainamide These drugs can cause SLE.