Vomiting rifampicin

The adverse effects of amprenavir in patients treated with combination therapy included nausea, vomiting, diarrhea, epigastric pain, flatulence, paresthesia, headache, rash, and fatigue (4). The contribution of a single drug to the observed adverse effects is difficult to establish. Amprenavir inhibits CYP3A4 to a greater extent than saquinavir, and to a much lesser extent than ritonavir (5). Co-administration with rifampicin and rifabutin should be avoided. Those who take... 

Severe overdosage has been observed in inadvertent administration of an excessive dose of rifampicin in children (93) and also in suicide attempts (94,95). It can also occur when there is impaired hepatic function or severe renal insufficiency. Symptoms are nausea, vomiting, headache, abdominal pain, diarrhea, and pruritus. 

The reasons for the hepatotoxicity are not fully understood but rifampicin or isoniazid alone can cause liver damage by their own toxic action. One suggestion is that the rifampicin alters the metabolism of isoniazid, resulting in the formation of hydrazine, which has proven to be hepatotoxic. Higher plasma levels of hydrazine are said to occur in slow acetylators of isoniazid, but one study failed to confirm that this is so. There has certainly been at least one fatality caused by this combina-tion. The manufacturers of rifampicin advise that caution is particularly needed in patients with impaired liver function, the elderly, malnourished patients, and children under two years of age. After baseline LFTs, further tests are only needed if fever, vomiting, or jaundice occur, or if the patient deteriorates. However, the manufacturers of isoniazid suggest that liver function tests should be reviewed regularly in patients on combined treatment. ... 

Drug-drug iuteractious Atazanavir -f ritonavir In a phase I, open, one-arm study, 14 HIV-seronegative volunteers first took rifampicin 600 mg/day for 8 days and then added atazanavir 300 mg bd and ritonavir 100 mg bd however, when atazanavir and ritonavir were added, the first three subjects developed vomiting and rises in aminotransferases and the study was terminated [83 ]. 

A brief, but interesting communication from the United States described the incidence of adverse effects in 61 healthy subjects who elected to take rifampicin prophyl-actically after being in close contact with a patient who died of meningococcal meningitis. Only 18 of the 61 people reported no adverse reactions. The dosage used was 600 mg every 12 hours for 4 doses. Six of the subjects were unable to take all 4 doses because of side effects. The commonest reactions were nausea, headache, dizziness and vomiting (24 ). 

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