Major
Rifampicin × Simvastatin
Antituberculous antibiotic×HMG-CoA reductase inhibitors (statins)
Mechanism
Rifampicin strongly induces CYP3A4 and the OATP1B1 transporter – the routes of simvastatin activation and hepatocyte uptake. Simvastatin plasma levels fall by 87%; lipid-lowering effect practically disappears.
Symptoms
The patient feels nothing. Laboratory: LDL cholesterol and total cholesterol rise. In high cardiovascular risk patients, myocardial infarction and stroke risk increase.
Management
During anti-TB therapy, switch simvastatin to pravastatin (less induction-sensitive metabolism). Induction persists for 2 weeks after rifampicin stops – reintroduce simvastatin gradually.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.