Drug Interaction Report
2 potential interactions and/or warnings found for the following 2 drugs:
- mibefradil
- rifampin
Interactions between your drugs
rifAMPin mibefradil
Applies to: rifampin, mibefradil
Consumer information for this interaction is not currently available.
GENERALLY AVOID: Potent inducers of CYP450 3A4 may significantly decrease the plasma concentrations of most calcium channel blockers (CCBs), as CYP450 3A4 is the primary isoenzyme responsible for their metabolism. Some drug interaction studies have reported a significant reduction in plasma levels for certain CCBs. For example, when a single dose of nimodipine (60 mg) was administered to patients with epilepsy (n=8) who were also receiving chronic treatment with a potent CYP450 3A4-inducing antiepileptic agent (phenytoin, phenobarbital and/or carbamazepine), the mean areas under the plasma nimodipine concentration curve (AUC) were lowered by about 7-fold compared to the control group. In another drug interaction study comparing nisoldipine pharmacokinetics in epileptic patients on concurrent phenytoin therapy (n=12) to healthy controls (n=12), the AUC of nisoldipine was approximately 90% lower (1.6 vs 15.2 mcg/L/h) in patients on concomitant phenytoin therapy. Clinical data for all calcium channel blockers with potent CYP450 3A4 inducers are not available.
MANAGEMENT: Concomitant use of calcium channel blockers (CCBs) primarily metabolized by CYP450 3A4 with potent CYP450 3A4 inducers should generally be avoided. Additional monitoring and dose adjustments may be required if coadministration is necessary, particularly during initiation, titration, or discontinuation of the CYP450 3A4 inducer. Individual product labeling for the CCB should be consulted for further guidance.
Drug and food interactions
rifAMPin food
Applies to: rifampin
Food can decrease the levels of rifAMPin in your body. Taking rifAMPin on an empty stomach (at least 30 minutes before or 2 hours after a meal) will make it easier for your body to absorb the medication. Avoid drinking alcohol while taking rifAMPin because alcohol use may increase the risk of damage to your liver. It is important to seek immediate medical care if you experience any severe side effects or symptoms of liver damage such as fever, chills, joint pain or swelling, unusual bleeding or bruising, skin rash, itching, loss of appetite, fatigue, nausea, vomiting, dark colored urine, and/or yellowing of the skin or eyes. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.
Therapeutic duplication warnings
No duplication warnings were found for your selected drugs.
Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.
Drug Interaction Classification
| Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit. | |
| Moderately clinically significant. Usually avoid combinations; use it only under special circumstances. | |
| Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan. | |
| No interaction information available. |
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Further information
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