Are there any reports on cross-reactivity between the selective MAO-A (mono-amine oxidase A inhibit

Fråga: Are there any reports on cross-reactivity between the selective MAO-A (mono-amine oxidase A inhibitor) moclobemide and non-selective MAO inhibitors regarding cutaneous adverse drug reactions?

A woman needs pharmacological treatment for depression. Medication with SSRI:s and TCA:s resulted in intolerable side effects. Moclobemide had an excellent antidepressive effect, but unfortunately caused wide-spread exanthema after two weeks´ use. A de- and a rechallenge were made, both positive. The doctor now considers trying one of the older non-selective MAO inhibitors.

Sammanfattning: There is no information on cross-reactivity between moclobemide and the non-selective MAO inhibitors phenelzine, tranylcypromine or nialamide. Chemically, they have little resemblance and as long as the adverse reactions to moclobemide are not too severe, changing to another MAO inhibitor seems rational.

Svar: No information on cross-reactivity between moclobemide and other MAO-inhibitors was found in Medline, Drugline or standard pharmacological literature. In Swedis, there were 305 reports of adverse reactions during moclobemide treatment, where a causal relationship had been judged possible or probable (1). Of these, 27 (9 percent) were skin reactions, mainly urticaria and exanthema. For the non-selective MAO-inhibitor phenelzine, the corresponding numbers were 20 (total) and 2 (skin reactions). There were very few reports on tranylcypromine and nialamide.

Chemically, moclobemide has little resemblance to phenelzine, tranylcypromine or nialamide (2-5). Consequently, the risk of cross-reactivity is theoretically low. 1 Swedis (The Swedish Drug Information System)

2 Dollery C Sir, editor. Therapeutic drugs. 2nd ed. Edinburgh: Churchill Livingstone; 1999. p. M209
3 Dollery C Sir, editor. Therapeutic drugs. 2nd ed. Edinburgh: Churchill Livingstone; 1999. p. P74
4 Dollery C Sir, editor. Therapeutic drugs. 2nd ed. Edinburgh: Churchill Livingstone; 1999. p. T154

5 Windholz M, Budavari S, Blumetti RF, Otterbein ES (eds), The Merck Index. An encyclopedia of chemicals, drugs, and biologicals. 10th ed. Rahway, NJ, USA: Merck & Co., Inc.; 1983. p. 930-1