OBJECT DRUGS
Ergot Alkaloids:
- Dihydroergotamine (D.H.E. 45, etc.)
- Ergotamine (Bellergal-S, Cafergot, Ergomar, Wigraine)
- Methysergide (Sansert)
PRECIPITANT DRUGS
Antidepressants:
- Fluvoxamine (Luvox, etc.)
- Nefazodone
Comment:
Ergotamine (and probably dihydroergotamine and methysergide) undergo first-pass metabolism by CYP3A4, and several reports of ergotism have appeared when CYP3A4 inhibitors were given concurrently. Fluvoxamine appears to be a modest CYP3A4 inhibitor but may produce increased ergotamine concentrations. Theoretically non-oral routes of ergot administration would interact much less than the oral route.
Class 2: Use Only if Benefit Felt to Outweigh Risk
- Use Alternative:Sertraline (Zoloft), citalopram (Celexa), escitalopram (Lexapro), venlafaxine (Effexor), and paroxetine (Paxil) appear less likely to inhibit CYP3A4 than fluvoxamine. Fluoxetine (Prozac) appears to be a weak inhibitor of CYP3A4. Little is known about the effects of other antidepressants on ergot alkaloids.
- Monitor: If the combination is used, monitor carefully for evidence of ergotism such as ischemia of extremities (pain, tenderness, cyanosis, and low skin temperature), hypertension, and tongue ischemia.