Ritonavir or Norvir is an anti-viral drug which is used in infections such as HIV and AIDS.
Ritonavir or Norvir is a protease inhibitor which means it blocks an enzyme - protease - which the virus needs to reproduce.
HIV infections have the ability to develop a resistance to Ritonavir or Norvir. For this reason Ritonavir or Norvir is often given in combination with other AIDS drugs which reduces the development of resistance. If resistance does develop other protease inhibitors - indinavir, saquinavir - can be used.
Ritonavir or Norvir can cause nausea, vomiting, diarrhea, a feeling of numbness, altered tastes, and a rise in cholesterol levels. To reduce these side effects Ritonavir or Norvir can be taken with food. Liquid Ritonavir or Norvir can be taken with liquids such as chocolate milk or liquid nutritional supplements to reduce the unpleasant taste.
Ritonavir or Norvir is heat sensitive, meaning that it should be stored in the refrigerator.
Because Ritonavir or Norvir affects the liver's function, people with liver problems will require monitoring of their liver's function.
Rifampin, rifabutin, dexamethasone, and anticonvulsants induce liver enzymes, which increase the metabolism of Ritonavir or Norvir and reduce the concentrations in the body.
With the non sedating antihistamines, terfenadine and astemizole, Ritonavir or Norvir can produce potentially fatal heart beat irregularities. Ritonavir or Norvir inhibits enzymes which metabolize these antihistamines in the liver, meaning that the levels of the antihistamines increase in the body.
Because Ritonavir or Norvir inhibits liver enzymes dosage adjustments of some drugs - diazepam, meperidine, triazolam, warfarin, clarithromycin - may be needed.
Med Letter 1996;38:35
New Engl J Med 1995;333:1528,1534
The relevant product monographs must be regarded as the appropriate sources of prescribing information.