During Continuous Daily or Intermittent Therapy: Rifampicin-Associated: Rifampicin may cause reddish discoloration of body fluids and occasionally other body secretions eg, urine, sputum, lacrimal fluid, feces, saliva and sweat. It may permanently discolor soft contact lenses.
Hepatic Effects: Very common (>10%) is an asymptomatic increase in liver enzymes; severe life-threatening hepatic reactions eg, hepatic failure and acute fulminant hepatitis are uncommon (>0.1% and <1%). In isolated cases (<0.01%), a fatal outcome was observed.
Renal effects (eg, elevations of BUN and serum uric acid, hemolysis, hematuria, intestinal nephritis and renal insufficiency).
Gastrointestinal tract (eg, nausea, abdominal pains, vomiting or diarrhea, and pseudomembranous colitis).
Effects on the central and peripheral nervous system (eg, tiredness, drowsiness, headache, dizziness, ataxia, mental confusion, muscular weakness and visual disturbances).
Hematological changes (eg, leukopenia, eosinophilia, thrombocytopenia and thrombocytopenic purpura).
Effects on skin and appendages (eg, flushing, itching with or without skin rash, urticaria, reddening of the eyes, exudative conjunctivitis or generalised hypersensitivity reactions involving the skin eg, exfoliative dermatitis, Lyell's syndrome and pemphigoid reactions).
Endocrine effects (eg, disturbances in the menstrual cycle and induction of crisis in Addison patients).
During Intermittent Therapy or Upon Resumption of Treatment after Temporary Interruption: In patients taking rifampicin other than on a daily basis or in those resuming treatment with the drug after a temporary interruption, an influenza-like syndrome (flu syndrome) may occur, this being very probably of immunopathological origin. It is characterized by fever, shivering and possibly headache, dizziness and musculoskeletal pain. In rare cases the flu syndrome may be followed by thrombocytopenia, purpura, dyspnea, asthma-like attacks, hemolytic anemia, shock and acute renal failure. These serious complications may, however, also set in suddenly with no preceding flu syndrome, chiefly when treatment is resumed after a temporary interruption or when rifampicin is given only once a week in high doses (≥25 mg/kg). When rifampicin is administered in lower doses (600 mg) 2-3 times a week, the syndrome is encountered less frequently, its incidence then being comparable to that observed during daily medication.
Isoniazid-Associated: Hepatic effects (eg, disturbances of liver function and hepatitis). The common prodromal symptoms of severe hepatitis are anorexia, nausea, vomiting, fatigue, malaise and weakness. The frequency of progressive liver damage increases with age. It is rare in persons <20, but occurs in up to 2.3% of those >50 years.
Gastrointestinal effects (eg, nausea, vomiting and epigastric distress).
Effects on the central nervous system (eg, peripheral neuropathy usually preceded by paraesthesias of feet and hands, damage to the optic nerve, convulsions, psychoses, dizziness, lightheadedness, headache and toxic encephalopathy).
Hematological changes (eg, agranulocytosis, eosinophilia, thrombocytopenia and anemia).
Allergic and miscellaneous reactions (eg, drug rash, fever, dryness of the mouth, heartburn, disorders of micturition, rheumatic syndrome, lupus erythematosus-like signs and symptoms, pellagra, gynecomastia, vasculitis, lymphadenopathy, hyperglycemia and metabolic acidosis).
Pyrazinamide-Associated: Hepatic effects (eg, transient rises in serum transaminase level, hepatotoxicity, hepatomegaly and jaundice).
Renal effects (eg, hyperuricemia, intestinal nephritis and dysuria).
Gastrointestinal reactions (eg, nausea, vomiting and anorexia).
Hematological changes (thrombocytopenia, sideroblastic anemia and adverse effects on blood clotting mechanisms).
Allergic and miscellaneous effects (mild arthralgia and myalgia, skin rash, photosensitivity, urticaria, pruritus, fever, acne and porphyria).
Ethambutol-Associated: Effects on the central and peripheral nervous system (eg, confusion, disorientation, hallucinations, headache, dizziness and malaise).
Visual disturbances (eg, neuritis causing a restriction in visual acuity, constriction of visual field, dark spots in the visual field and red-green color blindness).
Hepatic effects (eg, jaundice and transient liver dysfunction).
Gastrointestinal effects (eg, nausea, vomiting, anorexia and abdominal pain).
Hematological changes (eg, leucopenia and thrombocytopenia).
Allergic effects and miscellaneous effects (eg, skin rash, pruritus, fever and joint pains) (rarely).
Acute gout (rarely).