Which side effect should patients be specifically monitored for when on INH?

Monitoring for liver toxicity and hepatitis is crucial for patients receiving isoniazid (INH) because this medication is known to significantly impact liver function. INH is metabolized in the liver, and in some individuals, it can cause hepatocellular injury, leading to elevated liver enzymes and, in more severe cases, symptomatic hepatitis.

Patients are often monitored through regular blood tests to check liver enzyme levels such as AST (aspartate aminotransferase) and ALT (alanine aminotransferase). Symptoms of liver toxicity may include jaundice, abdominal pain, and unusual fatigue, which are key indicators that should not be overlooked.

While the other potential side effects, like drowsiness, skin rashes, and weight changes, may also occur, they are not as critical or life-threatening as the hepatic effects. Therefore, close surveillance for liver health is particularly important during INH treatment to prevent serious complications.