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Drug Interactions between black cohosh and ritonavir

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Moderate

ritonavir black cohosh

Applies to: ritonavir and black cohosh

GENERALLY AVOID: Concomitant use of black cohosh (Cimicifuga racemosa rhizome) with other agents that are known to induce hepatotoxicity may theoretically increase the risk of liver injury. Black cohosh has been suspected in rare cases of liver toxicity ranging from abnormal liver function tests and jaundice to various forms of hepatitis and hepatic failure requiring transplantation. The onset has typically been within the first 3 months after initiation of black cohosh. Although approximately half of the cases resulted in hospitalization, most improved or resolved following discontinuation of the product. Many of the cases were not well documented with respect to the specific herbal formulation and dose used or timeframe of treatment in relation to onset of reaction, or they were complicated by multiple confounding factors. Some of the cases also involved products containing multiple herbal or other medicinal substances. Nevertheless, the European Medicines Agency (EMEA) and the Committee on Herbal Medicinal Products (HMPC) reviewed 42 such cases and released an assessment statement in 2006 indicating a potential connection between products containing Cimicifuga racemosa rhizome and human hepatotoxicity. The Medicines and Healthcare products Regulatory Agency (MHRA) in the U.K. also issued an assessment report supporting a causal association after reviewing data from over 40 cases received through their reporting system and similar systems in other countries, as well as in the published literature. Hepatotoxicity warnings are currently required on products containing black cohosh marketed in many European countries and Australia.

MANAGEMENT: Until more information is available, patients should consider avoiding the use of black cohosh if they are receiving other potentially hepatotoxic agents (e.g., acetaminophen; alcohol; androgens and anabolic steroids; antituberculous agents; azole antifungal agents; ACE inhibitors; cyclosporine (high dosages); disulfiram; endothelin receptor antagonists; interferons; ketolide and macrolide antibiotics; kinase inhibitors; minocycline; nonsteroidal anti-inflammatory agents; nucleoside reverse transcriptase inhibitors; proteasome inhibitors; retinoids; sulfonamides; tamoxifen; thiazolidinediones; tolvaptan; vincristine; zileuton; anticonvulsants such as carbamazepine, hydantoins, felbamate, and valproic acid; lipid-lowering medications such as fenofibrate, lomitapide, mipomersen, niacin, and statins; other herbals and nutritional supplements such as chaparral, comfrey, DHEA, kava, pennyroyal oil, and red yeast rice). Patients should be advised to seek medical attention if they experience potential signs and symptoms of hepatotoxicity such as fever, rash, itching, anorexia, nausea, vomiting, fatigue, malaise, right upper quadrant pain, dark urine, pale stools, and jaundice.

References

  1. Westphal JF, Vetter D, Brogard JM (1994) "Hepatic side-effects of antibiotics." J Antimicrob Chemother, 33, p. 387-401
  2. Whiting PW, Clouston A, Kerlin P (2002) "Black cohosh and other herbal remedies associated with acute hepatitis." Med J Aust, 177, p. 440-3
  3. Lee WM (2003) "Drug-induced hepatotoxicity." N Engl J Med, 349, p. 474-85
  4. Low Dog T (2005) "Menopause: a review of botanical dietary supplements." Am J Med, 118(12 Suppl 2), p. 98-108
  5. Therapeutic Research Faculty (2008) Natural Medicines Comprehensive Database. http://www.naturaldatabase.com
  6. MHRA UKPAR (2008) Black Cohosh: UK Public Assessment Report. http://www.mhra.gov.uk/home/groups/es-herbal/documents/websiteresources/con2024279.pdf
View all 6 references

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Drug and food interactions

Moderate

ritonavir food

Applies to: ritonavir

ADJUST DOSING INTERVAL: Administration with food may modestly affect the bioavailability of ritonavir from the various available formulations. When the oral solution was given under nonfasting conditions, peak ritonavir concentrations decreased 23% and the extent of absorption decreased 7% relative to fasting conditions. Dilution of the oral solution (within one hour of dosing) with 240 mL of chocolate milk or a nutritional supplement (Advera or Ensure) did not significantly affect the extent and rate of ritonavir absorption. When a single 100 mg dose of the tablet was administered with a high-fat meal (907 kcal; 52% fat, 15% protein, 33% carbohydrates), approximately 20% decreases in mean peak concentration (Cmax) and systemic exposure (AUC) were observed relative to administration after fasting. Similar decreases in Cmax and AUC were reported when the tablet was administered with a moderate-fat meal. In contrast, the extent of absorption of ritonavir from the soft gelatin capsule formulation was 13% higher when administered with a meal (615 KCal; 14.5% fat, 9% protein, and 76% carbohydrate) relative to fasting.

MANAGEMENT: Ritonavir should be taken with meals to enhance gastrointestinal tolerability.

References

  1. (2001) "Product Information. Norvir (ritonavir)." Abbott Pharmaceutical

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Therapeutic duplication warnings

No 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.


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Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor 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.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.