Atorvastatin is generally well tolerated. The adverse effects observed are usually mild and transient. The most frequently reported side effects (1% or more) include constipation, flatulence, dyspepsia, abdominal pain, headache, nausea, myalgia, asthenia, diarrhoea, and insomnia, elevated serum ALT levels; elevated serum CPK levels (atorvastatin causes less elevation of serum CPK levels as compared to other HMG-CoA reductase inhibitors).
Rarely muscle pain, tenderness or weakness has been observed. Muscle cramps, myositis, myopathy, paraesthesia, peripheral neuropathy, pancreatitis, hepatitis, cholestatic jaundice, anorexia, vomiting, alopecia, pruritus, rash, impotence, hyperglycaemia, chest pain, dizziness, angina and allergic reaction have been reported during clinical trials. Not all of the above mentioned effects have necessarily been associated with atorvastatin therapy.