ABSTRACT
Avoid co-administration. If absolutely necessary, advise patients to discontinue treatment immediately if numbness and tingling of the extremities are felt
ERGOT DERIVATIVES ANTIVIRALS – PROTEASE INHIBITORS, EFAVIRENZ
≠ ergotamine/methysergide levels with risk of toxicity
↓ CYP3A4-mediated metabolism of ergot derivatives
Avoid co-administration
ERGOT DERIVATIVES BETA-BLOCKERS Three cases of arterial vasoconstriction and one of ≠ BP occurred when ergotamine or methysergide was added to propanolol or oxprenolol
Ergotamine can cause peripheral vasospasm, and absence of betaadrenergic activity can ≠ risk of vasoconstriction
Ergot derivatives and beta-blockers are often co-administered without trouble; however, monitor BP at least weekly until stable (watch for ≠ BP) and warn patients to stop the ergot derivative and seek medical attention if they develop cold, painful feet
N ER
V O
U SSY
STEM D
R U
G S
A N
TIM IG
R A
IN ED
R U
G S229
NERVOUS SYSTEM DRUGS ANTIMIGRAINE DRUGS Ergot derivatives
gangrene
Possibly ≠ bioavailability by ↓ presystemic metabolism. Constituents of grapefruit juice irreversibly inhibit intestinal cytochrome CYP3A4
Monitor for ≠ side-effects and stop intake of grapefruit preparations if side-effects occur
ERGOT DERIVATIVES H2 RECEPTOR BLOCKERS – CIMETIDINE
≠ ergotamine/methysergide levels with risk of toxicity
Inhibition of metabolism via CYP3A4
Avoid co-administration
ERGOTAMINE, METHYSERGIDE
5-HT1 AGONISTS – TRIPTANS
≠ risk of vasospasm Additive effect 1. Do not administer ergotamine and almotriptan, rizatriptan, sumatriptan or zolmitriptan within 6 hours of each other 2. Do not administer methysergide and almotriptan, rizatriptan, sumatriptan or zolmitriptan within 24 hours of each other 3. Do not administer an ergot derivative and eletriptan or frovatriptan within 24 hours of each other
ERGOT DERIVATIVES SYMPATHOMIMETICS
ERGOT DERIVATIVES SYMPATHOMIMETICS Risk of ergot toxicity when ergotamine is co-administered with sympathomimetics
Uncertain Watch for early features of ergotamine toxicity (vertigo and gastrointestinal disturbance)
ERGOT DERIVATIVES DIRECT Case report of gangrene when dopamine was given to a patient on ergotamine
Thought to be due to additive vasoconstriction
Titrate dopamine carefully
N ER
V O
U SSY
STEM D
R U
G S
A N
TIM IG
R A
IN ED
R U
G S
Mechanism Precautions
ALMOTRIPTAN, ELETRIPTAN
MACROLIDES – CLARITHROMYCIN, ERYTHROMYCIN, TELITHROMYCIN
≠ plasma concentrations of almotriptan and eletriptan, with risk of toxic effects, e.g. flushing, sensations of tingling, heat, heaviness, pressure or tightness of any part of body including the throat and chest, dizziness
Almotriptan is metabolized mainly by CYP3A4 isoenzymes. Most CYP isoenzymes are inhibited by clarithromycin to varying degrees, and since there is an alternative pathway of metabolism by MAOA, toxicity responses will vary between individuals
Avoid co-administration
ALMOTRIPTAN RIFAMPICIN Possible ↓ plasma concentrations of almotriptan, with risk of inadequate therapeutic efficacy
One of the major metabolizing enzymes of almotriptan – CYP3A4 isoenzymes – are induced by rifampicin. As there are alternative metabolic pathways, the effect may not be significant and can vary from individual to individual
Be aware of the possibility of ↓ response to triptan, and consider ≠ of dose if considered to be due to interaction
ZOLMITRIPTAN QUINOLONES Possible ↓ plasma concentrations of zolmitriptan, with risk of inadequate therapeutic efficacy
Possibly induced metabolism of zolmitriptan
Be aware of possibility of ↓ response to triptan, and consider ≠ of dose if considered to be due to interaction.
