Side-effects

The commonest side-effects of saquinavir (Invirase) are diarrhoea, abdominal discomfort, headache and nausea. These are most likely to occur during the early weeks of treatment. Medicines to control nausea, diarrhoea and headache can be prescribed before starting saquinavir. The risk of side-effects is increased if saquinavir is combined with ritonavir.

As a class, protease inhibitors have been associated with a syndrome of fat and metabolic irregularities. This syndrome includes body fat redistribution, high fat levels in the blood, diabetes, increased levels of blood sugar and increased bleeding in haemophiliacs. For more details, see Metabolic changes while on ART.

Saquinavir is not linked to liver toxicity. There is a small risk that saquinavir treatment will result in irregular heart rhythm. The US FDA now recommends that patients should receive an electrocardiogram (ECG) prior to starting saquinavir, and all patients who experience abnormal heart rhythms while taking the drug should contact their doctor.

In the 48-week Gemini trial comparing the performance of SQV/r- and LPV/r-based regimens (both given with tenofovir and emtricitabine) when given to over 300 antiretroviral-naive patients, the following 24-week results were reported on in July 2007.¹ The percent increase of patients with total cholesterol (TC) >200 mg/dL was 22% in the SQV/r arm and 27% in the LPV/r arm (median TC increase was 17 vs 26 mg/dL respectively).

The percent increase of patients with triglyceride (TG) levels ≥400 mg/dL at week 24 was 1% in the SQV/r and 9% in the LPV/r arm (median TG increase of 14 vs 43 mg/dL). These results were statistically significant. The LDL and HDL levels were similar.

Five adverse events occurred in the SQV/r group and 11 in the LPV/r group. One participant in the LPV/r group experienced hepatic failure and died; the failure may have been related to study treatment.