Methyldopa/MAOIs Interactions

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

Medical warning:

Severe. These medicines may interact and cause very harmful effects and are usually not taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

Medicines that inhibit monoamine oxidase (MAOI's) may prevent your methyldopa from working.

What might happen:

Your blood pressure may increase and you may experience hallucinations.

What you should do about this interaction:

Let your healthcare professionals (e.g. doctor or pharmacist) know right away that you are taking these medicines together. If your doctor decides that this is best therapy for you, you may need to check your blood pressure more often. Let your doctor know if it is high or higher than normal for you or if you develop hallucinations.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.

  • 1.Aldomet (methyldopa) UK summary of product characteristics. Merck Sharp & Dohme Limited August 16, 2001.
  • 2.Nardil (phenelzine sulfate) US prescribing information. Parke-Davis May, 2007.
  • 3.Paykel ES. Hallucinosis on combined methyldopa and pargyline. Br Med J 1966 Mar 26;5490:803.
  • 4.Hydopa (methyldopa) Australian prescribing information. Alphapharm March 12, 1999.
  • 5.Methyldopa US prescribing information. Mylan Pharmaceuticals Inc. October, 2012.
  • 6.Aldoril (methyldopa-hydrochlorothiazide) US prescribing information. Merck & Co., Inc. February, 2004.
  • 7.Ramsay RR, Dunford C, Gillman PK. Methylene blue and serotonin toxicity: inhibition of monoamine oxidase A (MAO A) confirms a theoretical prediction. Br J Pharmacol 2007 Nov;152(6):946-51.
  • 8.Peter C, Hongwan D, Kupfer A, Lauterburg BH. Pharmacokinetics and organ distribution of intravenous and oral methylene blue. Eur J Clin Pharmacol 2000 Jun;56(3):247-50.

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CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.