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Pharmacologic class: Niacinamide derivative
Therapeutic class: Antitubercular
Pregnancy risk category C
Unknown. Thought to exert bacteriostatic activity.
Tablets: 500 mg
Indications and dosages
Adults and children: 15 to 30 mg/kg/day P.O., not to exceed 2 g/day; or 50 to 70 mg/kg P.O. twice weekly, up to a maximum of 4 g/dose; or 50 to 70 mg/kg/dose P.O. three times weekly, up to a maximum of 3 g/dose
• Renal impairment
• Hypersensitivity to drug
• Severe hepatic disease
• Acute gout
Use cautiously in:
• renal failure, diabetes mellitus, porphyria, chronic gout, history of gout
• pregnant or breastfeeding patients
• children younger than age 13.
• Give with other antituberculars, as prescribed, to reduce risk of resistant organisms.
• Be aware that drug therapy may last 6 months or longer.
GI: nausea, vomiting, diarrhea, peptic ulcer, abdominal cramps, anorexia
GU: dysuria, increased uric acid secretion
Hematologic: hemolytic anemia
Metabolic: hyperuricemia, gout
Musculoskeletal: joint pain
Skin: urticaria, photosensitivity
Drug-drug. Ethionamide: increased risk of hepatotoxicity
Probenecid: decreased probenecid efficacy (possibly precipitating gout)
Drug-diagnostic tests. Acetest or Ketostix urine test: false interpretation
Liver function tests: abnormal results
Uric acid: increased level
• Monitor CBC, uric acid level, and liver and kidney function tests.
• Assess for signs and symptoms of gout, hepatic failure, and hemolytic anemia.
☞ Discontinue at first sign of hepatic impairment or hyperuricemia accompanied by acute gouty arthritis.
• Advise patient to take regularly with other antituberculars, as prescribed.
☞ Teach patient to recognize and immediately report signs and symptoms of gout and liver impairment.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.