What monitoring test is important for patients on INH therapy?

The monitoring of liver function tests is crucial for patients undergoing isoniazid (INH) therapy because INH is known to potentially cause hepatotoxicity. This means that it can lead to liver damage, which can be serious and sometimes life-threatening. Regular liver function tests help in early detection of any liver abnormalities, allowing for timely intervention if necessary.

Patients on INH should be monitored particularly for elevated liver enzymes such as AST (aspartate aminotransferase) and ALT (alanine aminotransferase). If these enzymes are significantly elevated, it may indicate that the patient's liver is reacting adversely to the medication, prompting the healthcare provider to either adjust the treatment plan or discontinue INH therapy altogether.

Other monitoring options listed do not provide the same level of risk assessment relative to INH therapy. For example, urine toxicology screens are not pertinent in monitoring side effects of INH, nor are skin allergy tests considered necessary for managing potential drug-related liver issues. Cardiac stress tests also do not relate to the primary concerns of INH therapy, which centers around liver health. Thus, liver function tests emerge as the most relevant and essential monitoring component during INH treatment.