Cautions with other medicines
Some medicines affect the way that simvastatin works and can increase the chances of you having serious side effects, such as muscle damage.
Tell your doctor or pharmacist if you are taking any of the following medicines:
- antibiotics, such as clarithromycin, rifampicin or fusidic acid
- medicines used to treat fungal infections, such as fluconazole or ketoconazole
- some HIV medicines
- medicines used to treat hepatitis C virus infection
- warfarin, a medicine used to help prevent blood clots
- ciclosporin, a medicine to treat psoriasis and rheumatoid arthritis
- danazol, a medicine to treat endometriosis
- amiodarone, a medicine that helps your heart rhythm get back to normal in atrial fibrillation
- verapamil, diltiazem or amlodipine, medicines for high blood pressure and heart problems
- colchicine, a medicine used to treat gout
If you're taking simvastatin and need to take one of these medicines, your doctor may:
- prescribe a lower dose of simvastatin
- prescribe a different statin medicine
- recommend that you stop taking your simvastatin for a while
Mixing simvastatin with herbal remedies and supplements
St John's wort, a herbal medicine taken for depression, reduces the level of simvastatin in your blood, so it does not work as well. Talk to your doctor if you're thinking about starting St John's wort, as it will change how well simvastatin works.
Tell your doctor or pharmacist if you are taking a Coenzyme Q10 (CoQ10) supplement. Supplements can affect the way other medicines you may also be taking work.
There is no clear evidence that taking CoQ10 at the same time as simvastatin will benefit your health. More research is needed.
There's not enough information to say that other herbal remedies and supplements are safe to take with simvastatin. They're not tested in the same way as pharmacy and prescription medicines. They're generally not tested for the effect they have on other medicines.