Atorvastatin (Lipitor) is a statin that can reduce the levels of low-density lipoprotein (LDL or ‘bad’) cholesterol in the blood. This can reduce the risk of cardiovascular disease, including heart attacks and strokes. Statins work by inhibiting the enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, which is resposible for the production of cholesterol.

Patients with liver disease or who are pregnant should not take statins. However, they are safe drugs in most patients. The main side-effects are muscle pain, as well as headache, altered liver function, tingling sensations, abdominal pain, flatulence, constipation, diarrhoea, nausea and vomiting.

Statins, including atorvastatin, are effective in the treatment of the alterations of blood fat levels due to treatment with anti-HIV drugs, particularly protease inhibitors^[1][2]. However, atorvastatin is broken down by the cytochrome P450 3A4 enzyme, and interacts with all available protease inhibitors and non-nucleoside reverse transcriptase inhibitors (NNRTIs).

Protease inhibitors cause an increase in atorvastatin levels, increasing the risk of side-effects such as muscle pain and damage to the muscle fibres^[3][4][5]. Consequently, patients taking protease inhibitors should use another statin such as pravastatin sodium (Lipostat) or fluvastatin (Lescol) in place of atorvastatin, or they should use the lowest possible dose of atorvastatin with caution.

In contrast, NNRTIs reduce the levels of atorvastatin, putting patients at risk of poor anti-cholesterol effects^[6]. Patients taking an NNRTI and atorvastatin should have their dose of atorvastatin adjusted as required to keep cholesterol levels low.

Some experts believe that statins may have anti-HIV properties in their own right. However, a recent study found that atorvastatin failed to prevent CD4 cell count declines in patients interrupting anti-HIV treatment^[7].