Arguably, the most confusing thing about MAOIs is keeping track of which medication is “tranylcypromine” and which is “phenelzine.” The following mnemonics work for me, and perhaps they will for you:
•Parnate = tranylcypromine. PAR should remind you of golf. Visualize yourself being TRANsported in a golf cart on your way to the green where you will hope to make PAR.
•Nardil = phenelzine. Convert “NARD” to NERD. NERDs have more PHEN (fun)!
I haven’t bothered with mnemonics for Marplan (isocarboxazid) or EMSAM (selegiline patch); they just don’t seem as perpetually confusing as the others.
Parnate (tranylcypromine). It comes in 10 mg pills, and is the most well-studied of the MAOIs. Dose it as high as 60 mg; clinicians comfortable with MAOIs sometimes go even higher. Although Dr. Jonathan Cole (in this month’s TCPR interview) does not seem convinced, Parnate tends to cause less sedation, but more insomnia, than Nardil, a difference that was demonstrated recently in the first headtohead comparison of two medications (Birkenhager et. al., J Clin Psychiatry 2004;65:1505-1510). Parnate is also more likely than Nardil to cause hypertension in combination with tyramine or adrenergic medication. This may be partly due to the fact that Parnate’s chemical structure is more amphetamine-like than any other MAOI.
Nardil (phenelzine). Nardil is the only MAOI that comes in 15 mg tablets, and the target dose is about 1 mg/kg, or 75 mg/day for many patients. It is considered the “high side effect” MAOI, because it causes sedation, weight gain, and sexual dysfunction. You might use Nardil first for particularly agitated patients and for those who seem less likely to follow the MAOI diet to the letter.
Marplan (isocarboxazid). Marplan, like Parnate, comes in 10 mg pills, and is dosed pretty much identically. Marplan was withdrawn from the U.S. market in 1994 for unclear reasons, apparently due primarily to the economics of marketing it. But it was “reapproved” by the FDA under new ownership (Roche Pharmaceuticals) and with a new, more generous maximum approved dose of 60 mg/day (vs. the former 30 mg/day). The scoop on Marplan is that it is better tolerated than Nardil, and a large metaanalysis reported that it has outperformed placebo more robustly than Parnate or Nardil (Thase et. al., Neuropsychopharmacology 1995;12:185-219).
Eldepryl (selegiline). For information on the selegiline patch, see the article in this issue. Oral selegiline is approved only as adjunctive treatment for patients with Parkinson’s Disease who are already taking L-Dopa. Nevertheless, it has been used in depression with reasonable success (Bodkin et. al., Psychiatric Ann 2001;31(6):385-391). It comes in 5 mg pills, and at doses no higher than 20 mg/day is MAO-B selective, meaning that it does not require dietary restrictions, though the usual MAOI drugdrug contraindications do apply. The target antidepressant dose is about 45 mg/day.
TCR VERDICT: There’s nothing like the classics!