All drugs are metabolized by acetylation EXCEPT:
Ans. (a) PhenytoinRef. KDT 125; katzung 11th ed. /80ACETYLATION* Compounds having amino or hydralazine residues are conjugated with the help of N-Acetyl transferase enzyme.# If acetylation is slow- its toxic# Fast acetylation- not effective or effectiveness decreases# Normal acetylation- effective* These drugs are remembered as SHIP drugs:# Sulfonamides (dapsone)# Hydralazine (anti HTN)# Isoniazid (anti TB)# Procainamide (anti-arrhythmic)* NOTE- phenytoin is an anti epileptic drug, which is always confused with procainamide in SHIP drugs. Phenytoin doesn't come under SHIP drugs.* Phenytoin hydroxylation in liver is carried out by cytochrome P 450.* SHIP drugs causes SLE.
Phenytoin
Isoniazid
Procainamide
Hydralazine
Pharmacodynamics