Which tuberculosis medication requires adjustment in cases of renal disease?

Ethambutol is the medication that requires dosage adjustment in cases of renal disease. The primary reason for this is that ethambutol is primarily excreted by the kidneys, and in patients with impaired renal function, the drug can accumulate in the body, leading to increased risk of toxicity. It's essential to adjust the dosage based on the level of renal impairment to maintain effective treatment while minimizing the risk of adverse effects, such as optic neuritis.

In contrast, the other medications listed—isoniazid, rifampicin, and pyrazinamide—have different pharmacokinetic profiles. For example, isoniazid is mainly metabolized by the liver, and while it can have interactions with renal function, direct renal dosing adjustments are less frequently necessary. Rifampicin also undergoes extensive hepatic metabolism, which reduces the necessity for renal dose modifications. Pyrazinamide is somewhat more complex, as it is also largely metabolized by the liver, and while its use in renal impairment doesn't usually require standard adjustment, careful monitoring is essential.

Therefore, understanding the pharmacokinetics and metabolic pathways of these drugs is crucial for determining appropriate adjustments in the presence of renal disease, making ethambutol the clear choice for requiring such adjustments