Drug	Main adverse effects		Monitoring parameters
Isoniazid	Hepatotoxicity Lupus-like syndrome Peripheral neuropathy		Monitor LFTs and for flushing and decreased sensation in extremities LFTs should be monitored monthly in patients who are at a higher risk of hepatotoxicity,* have preexisting liver disease, or develop abnormal LFT results LFTs should also be checked in patients who develop clinical symptoms of hepatitis; isoniazid should be discontinued if findings on LFTs increase by more than five times the upper limits of normal in paients without symptoms of hepatotoxicity and by more than three times the upper limits of normal in patients with symptoms†
	Monoamine toxicity		If flushing occurs, patients should be counseled to avoid foods with high concentrations of monoamines (e.g., aged cheeses, wine)
Rifampin (Rifadin)‡	Drug Interactions		Baseline laboratory tests (including complete blood count and serum creatinine measurements) and monthly; every-other-month; or one-, three-, or six-month monitoring of LFTs and clinical symptoms are acceptable for most patients, but not required LFTs should be monitored monthly or twice monthly in patients who are at a higher risk of hepatotoxicity,* have preexisting liver disease, or develop abnormal LFT results
	Hepatotoxicity
	Immunologic reactions
		Acute renal failure
		Influenza-like symptoms
		Hemolytic anemia, thrombocytopenia (with potential for acute renal failure)
		Pruritus (with or without rash)
	Orange discoloration of body fluids		Patients should be counseled about the risk of contact lens discoloration
Pyrazinamide	Arthralgias Gastrointestinal upset Hepatotoxicity Rash		Baseline LFTs; serum creatinine may be assessed at baseline for dosing adjustments LFTs should be monitored monthly or twice monthly in patients who are at a higher risk of hepatotoxicity* or who have underlying hepatic dysfunction
	Hyperuricemia		Check uric acid levels if patient is symptomatic
Ethambutol (Myambutol)	Optic neuritis		Baseline and monthly testing of visual acuity and color discrimination; serum creatinine may be assessed at baseline for dosing adjustments