Indications: HIV infection in combination with other antiretroviral drugs; low doses used to increase effect of some protease inhibitors.

Cautions: concomitant use with drugs that prolong PR

interval; cardiac conduction disorders, structural heart disease; pancreatitis.

Contra-indications: acute porphyria.

Hepatic impairment: avoid in decompensated liver disease (in severe impairment without decompensation, use ‘booster’ doses with caution (avoid treatment doses)).

Pregnancy: only use low-dose booster to increase the effect of other protease inhibitors Pregnancies in HIV- positive women and babies born to them should be reported prospectively to the National Study of HIV in pregnancy and Childhoodand to the Antiretroviral pregnancy Registry. Mitochondrial dysfunction has been reported in infants exposed to nucleoside reverse transcriptase inhibitors in utero; the main effects include haematological, metabolic, and neurological disorders; all infants whose mothers received nucleoside reverse transcriptase inhibitors during pregnancy should be monitored for relevant signs or symptoms.

Breast-feeding: by HIV-positive mothers may cause HIV infection in the infant and should be avoided.

Side Effects: most common gastro-intestinal haemorrhage, blood pressure changes, oedema, syncope, flushing, cough, pharyngitis, anxiety, confusion, seizures, peripheral neuropathy, fever, decreased blood thyroxine concentration, menorrhagia, renal impairment, arthralgia, blurred vision, mouth ulcers, acne. less commonly myocardial infarction, electrolyte disturbances. Rarely toxic epidermal necrolysis

Side Effects: of the protease inhibitors include gastro- intestinal disturbances (including diarrhoea, nausea, vomiting, abdominal pain, flatulence), anorexia, hepatic dysfunction, pancreatitis; blood disorders including anaemia, neutropenia, and thrombocytopenia; sleep disturbances, fatigue, headache, dizziness, paraesthesia, myalgia, myositis, rhabdomyolysis; taste disturbances; rash, pruritus, Stevens-Johnson syndrome, hypersensitivity reactions including anaphylaxis.

Dose Initially 300 mg every 12 hours for 3 days, increased in steps of 100 mg every 12 hours over notlonger than 14 days to 600 mg every 12 hours. Low- dose booster to increase effect of other protease inhibitors, 100–200 mg once or twice daily.