Methyldopa (drug interactions)
Methyldopa is a medication commonly used to help control hypertension (high blood pressure). However, it is important to be aware of several potential drug interactions that could affect its efficacy and safety. Certain supplements and medications, such as Coenzyme Q 10, iron, monoamine oxidase (MAO) inhibitors, haloperidol, levodopa, lithium, and various antihypertensive agents, can interfere with the effects of methyldopa. Specifically, iron supplements should be taken at least two hours apart from methyldopa to prevent absorption issues. Additionally, substances like licorice and ephedra may counteract the blood pressure-lowering effects of methyldopa, while St. John's wort is known to decrease its effectiveness due to interactions with multiple medications. Patients with specific medical conditions, including Parkinson's, kidney, or liver diseases, should consider avoiding methyldopa altogether. Understanding these interactions can help ensure the safe and effective use of methyldopa for managing hypertension.
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Methyldopa (drug interactions)
DEFINITION: A medication sometimes used to control hypertension.
INTERACTIONS: Coenzyme Q10, iron, monoamine oxidase (MAO) inhibitors, haloperidol, levodopa, lithium, and other medications for high blood pressure, licorice, ephedra, St. John's wort, various prescription medications
TRADE NAME: None - available in genetic formulations only
Coenzyme Q10 (CoQ10)
Effect: Supplementation Possibly Helpful
There is some evidence that methyldopa might impair the body’s ability to manufacture the substance CoQ10. Taking CoQ10 supplements might make sense as a general precaution, but no specific benefit has been established.
Iron
Effect: Take at a Different Time of Day
Iron supplements can interfere with the absorption of methyldopa, so people should be sure not to take iron during the two hours before or after using methyldopa.
Along with avoiding iron supplements, several other medications should be avoided while taking methyldopa. These include monoamine oxidase (MAO) inhibitors, haloperidol, levodopa, lithium, and antihypertensive medicines for high blood pressure. Licorice should be avoided because it can counteract the blood pressure-lowering effects of methyldopa. Ephedra should be avoided for the same reasons. Finally, because St. John’s wort interacts with myriad medications, it is suggested patients avoid taking it with methyldopa because it can decrease its effectiveness. Further, if the patient has specific medical issues, such as Parkinson’s disease, kidney disease, and liver disease, treatment with methyldopa should be avoided.
Bibliography
Campbell, N. R., and B. B. Hasinoff. "Iron Supplements: A Common Cause of Drug Interactions." British Journal of Clinical Pharmacology, vol. 31, 1991, pp. 251-255.
Campbell, N., V. Paddock, and R. Sundaram. "Alteration of Methyldopa Absorption, Metabolism, and Blood Pressure Control Caused by Ferrous Sulfate and Gluconate." Clinical Pharmacology and Therapeutics, vol. 43, 1988, pp. 381-386.
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