Nefazodone and Simvastatin interaction

ZOCOR is contraindicated in the following conditions: Concomitant use of strong CYP3A4 inhibitors (select azole anti-fungals, macrolide antibiotics, anti-viral medications, and nefazodone) [see Drug Interactions (7.1) ] .

Concomitant use of strong CYP3A4 inhibitors (select azole anti-fungals, macrolide antibiotics, anti-viral medications, and nefazodone) ( 4 , 7.1 )

Steps to Prevent or Reduce the Risk of Myopathy and Rhabdomyolysis The concomitant use of strong CYP3A4 inhibitors with ZOCOR is contraindicated.

Intervention: Concomitant use of strong CYP3A4 inhibitors with ZOCOR is contraindicated [see Contraindications (4) ] .

If treatment with a CYP3A4 inhibitor is unavoidable, suspend ZOCOR during the course of strong CYP3A4 inhibitor treatment.

HMG-CoA Reductase Inhibitors – When single 40 mg doses of simvastatin or atorvastatin, both substrates of CYP3A4, were given to healthy adult volunteers who had received nefazodone hydrochloride, 200 mg BID for 6 days, approximately 20 fold increases in plasma concentrations of simvastatin and simvastatin acid and 3 to 4 fold increases in plasma concentrations…

Rhabdomyolysis has been observed in patients receiving HMG-CoA reductase inhibitors administered alone (at recommended dosages) and in particular, for certain drugs in this class, when given in combination with inhibitors of the CYP3A4 isozyme.

Caution should be used if nefazodone is administered in combination with HMG-CoA reductase inhibitors that are metabolized by CYP3A4, such as simvastatin, atorvastatin, and lovastatin, and dosage adjustments of these HMG-CoA reductase inhibitors are recommended.

Since metabolic interactions are unlikely between nefazodone and HMG-CoA reductase inhibitors that undergo little or no metabolism by the CYP3A4 isozyme, such as pravastatin or fluvastatin, dosage adjustments should not be necessary.

There have been rare reports of rhabdomyolysis involving patients receiving the combination of nefazodone and either simvastatin or lovastatin, also a substrate of CYP3A4 (see ADVERSE REACTIONS , Postintroduction Clinical Experience ).