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:
When these two medicines are taken together, your body may not process levodopa properly.
What might happen:
You may experience an increase in the toxic effects of levodopa including extremely high blood pressure, blurred vision, and muscle twitching.
What you should do about this interaction:
Contact your healthcare professionals (e.g. doctor or pharmacist) as soon as possible about taking these two medicines together. They may already be aware of this drug 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.Horwitz D, Goldberg LI, Sjoerdsma A. Increased blood pressure responses to dopamine and norephinephrine produced by monoamine oxidase inhibitors in man. J Lab Clin Med 1960 Nov;56(3):747-53.
2.Schildkraut JJ, Klerman GL, Friend DG, Greenblatt M. Biochemical and pressor effects of oral D,L-dihydroxyphenyalanine in patients pretreated with antidepressant drugs. 1963;107:1005-15.
3.Friend DG, Bell WR, Kline NS. The action of L-dihydroxyphenylalanine in patients receiving nialamide. Clin Pharmacol Ther 1965;6(3):362-6.
4.Hunter KR, Boakes AJ, Laurence DR, Stern GM. Monoamine oxidase inhibitors and L-dopa. Br Med J 1970 Aug 15;3(719):388.
5.Teychenne PF, Calne DB, Lewis PJ, Findley LJ. Interactions of levodopa with inhibitors of monoamine oxidase and L- aromatic amino acid decarboxylase. Clin Pharmacol Ther 1975 Sep;18(3):273-7.
6.Birkmayer W, Riederer P, Ambrozi L, Youdim MB. Implications of combined treatment with 'Madopar' and L-deprenil in Parkinson's disease. A long-term study. Lancet 1977 Feb 26;1(8009):439-43.
7.Sharpe J, Marquez-Julio A, Ashby P. Idiopathic orthostatic hypotension treated with levodopa and MAO inhibitor: a preliminary report. Can Med Assoc J 1972 Aug 19;107(4):296-300.
8.Eldepryl (selegiline) US prescribing information. Somerset Pharmaceuticals May, 1996.
9.Azilect (rasagiline) US prescribing information. Teva Neurosciences Inc. October, 2014.
10.Sinemet (carbidopa/levodopa) US prescribing information. Merck & Co., Inc February, 2011.
11.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.
12.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.
13.Emsam (selegiline) US prescribing information. Somerset August, 2007.