Relpax Drug Interactions: What to Avoid and What to Tell Your Doctor

Relpax (eletriptan) is a powerful migraine medication, but its effectiveness and safety depend heavily on what else you're taking at the same time. Several common medications can interact with eletriptan in ways that range from increasing side effects to causing life-threatening reactions.

This guide covers the most clinically significant drug interactions with eletriptan — and what to do about them.

The CYP3A4 Factor: Why Some Common Drugs Are Dangerous With Eletriptan

Eletriptan is metabolized primarily by the liver enzyme CYP3A4. When other drugs inhibit this enzyme, eletriptan is broken down more slowly — causing it to build up to potentially dangerous blood levels. Conversely, drugs that induce CYP3A4 cause eletriptan to be metabolized too quickly, reducing its effectiveness.

Major Interactions: Avoid These Within 72 Hours of Eletriptan

The following drugs are potent CYP3A4 inhibitors. Taking eletriptan within 72 hours (3 days) of these medications is contraindicated:

Antifungals: Ketoconazole, itraconazole, voriconazole — commonly prescribed for fungal infections. Wait at least 72 hours after completing the course before taking eletriptan.

Antibiotics: Clarithromycin (Biaxin), erythromycin, troleandomycin — macrolide antibiotics are frequently prescribed for respiratory infections. These interact significantly with eletriptan.

HIV protease inhibitors: Ritonavir (Norvir), nelfinavir (Viracept), cobicistat (found in Genvoya, Stribild) — strong CYP3A4 inhibitors used in HIV treatment. Eletriptan should be avoided while on these medications.

Nefazodone: An antidepressant that is also a potent CYP3A4 inhibitor. This interaction is contraindicated.

Avoid Within 24 Hours: Ergot Drugs and Other Triptans

Ergot medications: Dihydroergotamine (DHE, Migranal), ergotamine (Cafergot). Combining triptans with ergots can cause dangerous vasoconstriction — do not take within 24 hours of each other.

Other triptans: Sumatriptan, rizatriptan, zolmitriptan, naratriptan, almotriptan, frovatriptan. Do not take two triptans within 24 hours of each other — the risk of excessive vasoconstriction increases significantly.

Serotonin Syndrome Risk: SSRIs, SNRIs, and MAO Inhibitors

Serotonin syndrome is a potentially life-threatening condition caused by too much serotonin activity in the nervous system. Eletriptan can contribute to serotonin syndrome when combined with:

SSRIs: Fluoxetine (Prozac), sertraline (Zoloft), escitalopram (Lexapro), paroxetine (Paxil), citalopram (Celexa). These are among the most commonly prescribed antidepressants and are frequently taken by migraine patients.

SNRIs: Venlafaxine (Effexor), duloxetine (Cymbalta), desvenlafaxine (Pristiq). Like SSRIs, these are common and frequently co-prescribed with triptans.

MAO inhibitors: Phenelzine, tranylcypromine, selegiline. The interaction with MAOIs is serious — avoid eletriptan while taking an MAOI and for 2 weeks after stopping.

If you take an SSRI or SNRI for depression or anxiety and also use eletriptan for migraines, this combination is used clinically by many patients. The FDA requires a label warning, but the actual risk of serotonin syndrome with this specific combination is considered relatively low when used as directed. However, your doctor should be aware of the combination and monitor you accordingly.

Grapefruit Juice and Food Interactions

Grapefruit and grapefruit juice inhibit CYP3A4 in the gut and can increase eletriptan blood levels. While this is not an absolute contraindication, it's generally advisable to avoid grapefruit on days you take eletriptan, especially at higher doses.

CYP3A4 Inducers: Drugs That May Make Eletriptan Less Effective

Some medications speed up CYP3A4, causing eletriptan to be broken down too quickly and reducing its effectiveness:

Rifampin: Used for tuberculosis treatment; strong CYP3A4 inducer

Anti-seizure medications: Phenytoin (Dilantin), carbamazepine (Tegretol), phenobarbital

St. John's Wort: This herbal supplement is also a CYP3A4 inducer and has dual interactions — it both reduces eletriptan effectiveness and increases serotonin risk

What to Tell Your Doctor and Pharmacist

Before starting eletriptan, give your prescriber and pharmacist a complete list of everything you take — prescription medications, OTC drugs, vitamins, herbal supplements. The most critical items to flag:

Any antidepressant (especially SSRIs and SNRIs)

Any antibiotic, especially clarithromycin or erythromycin

Any antifungal medication

HIV medications (especially ritonavir or cobicistat-containing regimens)

Other migraine medications, including any other triptan or ergot

For a full overview of side effects and warning signs, read our Relpax side effects guide. For general information on uses and dosing, see what is Relpax.