Side-effects

Common side-effects of ritonavir (Norvir) include headache, nausea, vomiting, diarrhoea, dizziness, and tingling or numbness around the mouth. These are most likely to occur during the first weeks of treatment and there is evidence that women are more likely to suffer from these side-effects than men.1 2 Medicines to control nausea, diarrhoea and headache can be prescribed before starting ritonavir .

As a class, protease inhibitors have been associated with a syndrome of fat and metabolic irregularities. This syndrome includes altered body fat distribution, high fat levels in the blood, diabetes, increased levels of blood sugar and increased bleeding in haemophiliacs. Ritonavir has been associated with a more rapid and severe form of body fat changes than other protease inhibitors in some studies. It is also particularly associated with elevated in blood lipids such as cholesterol and triglycerides, although genetic variation in two apolipoprotein genes determines the risk of triglyceride elevations, at least in part.3 Combining ritonavir with another protease inhibitors may produce greater increases in triglyceride levels than a single protease inhibitor.4 5 For more details, see Metabolic changes while on ART.

Kidney failure is a rare, serious side-effect of ritonavir.6 It is more likely in people with pre-existing kidney problems or who are taking other drugs that are toxic to the kidneys.

While liver toxicity is a side-effect of full-dose ritonavir, it is not associated with the low doses used to boost the levels of other protease inhibitors, even in patients with hepatitis C co-infection.7

Low-dose ritonavir may also cause elevations of uric acid in the blood, which may lead to gout, particularly in patients with other risk factors.8

References

  1. Gatti C et al. Gender as a risk factor for ritonavir intolerance. 39th Interscience Conference on Antimicrobial Agents and Chemotherapy, San Francisco, abstract I238, 1999
  2. Currier J et al. Gender differences in adverse events on ritonavir: an analysis from the Abbott 247 study. First National Conference on Women and HIV, Pasadena, abstract 304.7, 1997
  3. Tarr PE et al. Modeling the influence of APOC3, APOE, and TNT polymorphisms on the risk of antiretroviral therapy-associated lipid disorders. J Infect Dis 191: 1419-1426, 2005
  4. McComsey GA et al. Effect of ritonavir-boosted protease inhibitor regimens on lipid profiles. 14th International AIDS Conference, Barcelona, abstract ThPeB7319, 2002b
  5. Shafran SD et al. The effect of low-dose ritonavir monotherapy on fasting serum lipid concentrations. HIV Med 6: 421-425, 2005
  6. Duong M et al. Renal failure after treatment with ritonavir. Lancet 348: 693, 1996
  7. Sulkowski MS et al. Hepatotoxicity associated with protease inhibitor-based antiretroviral regimens with or without concurrent ritonavir. AIDS 18: 2277-2284, 2004
  8. Creighton S et al. Is ritonavir boosting associated with gout? Int J STD AIDS 16: 362-364, 2005
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