How Long Does Relpax Stay in Your System?
Key Takeaways
- Relpax (eletriptan hydrobromide) has a half-life of about 4 hours, meaning most of the drug leaves your system within 24 hours.
- The effects of eletriptan are usually short-lived and designed to treat acute migraine attacks rather than prevent future headaches.
- Drug interactions, liver function, and other health conditions can affect how long Relpax stays in your body.
- Even after the medication is mostly cleared, side effects or interactions can still be relevant within the same 24-hour period.
- A healthcare provider can help determine safe timing for repeat doses or switching migraine treatments.
What Is Relpax?
Relpax is the brand name for eletriptan, an FDA-approved medication that belongs to the triptan class of medications. It is used in the treatment of migraine headaches with or without aura. It is not approved for cluster headaches or migraine prevention, but rather for treating active migraine attacks once symptoms begin.
Eletriptan works as a serotonin receptor agonist, targeting specific receptors on blood vessels in the brain. By narrowing dilated blood vessels and reducing inflammation, it helps relieve migraine symptoms such as throbbing head pain, nausea, light sensitivity, and sound sensitivity.
Relpax is taken as a single dose at the onset of migraine symptoms and may be repeated once within a 24-hour period if needed, depending on medical advice.
How Long Does Relpax Stay in Your System?
The length of time Relpax stays in your system depends largely on its half-life. The half-life of eletriptan is approximately 4 hours. A medication is generally considered mostly eliminated after about 5 half-lives.
Based on this:
- After 4 hours, about half the dose remains
- After 20 hours, most of the drug has been cleared
- Within 24 hours, eletriptan is largely out of the system
For most people, Relpax does not linger beyond one day. This short duration is intentional, as triptans are meant for acute migraine treatment rather than long-term use.
How Long Do the Effects of Relpax Last?
The effects of eletriptan usually begin within 30 to 60 minutes after the first dose. Migraine relief often lasts several hours, though symptoms can sometimes return.
If migraine symptoms come back, a second dose may be taken within the same 24-hour period, provided it does not exceed the maximum recommended dose. Taking more than advised can increase the risk of serious side effects.
Factors That Can Affect How Long Relpax Stays in the Body
Drug interactions
Several medications can slow the breakdown of eletriptan, causing it to stay in your system longer. These include:
- Ketoconazole
- Itraconazole
- Clarithromycin (Biaxin)
- Ritonavir (Norvir)
- Nelfinavir (Viracept)
- Nefazodone
- An ergotamine-containing or ergot-type medication such as dihydroergotamine (D.H.E. 45, Migranal) or methysergide.
Because of these interactions, Relpax should not be taken within at least 72 hours of certain strong CYP3A4 inhibitors. Be sure to let your healthcare provider know about any other prescription medications, over-the-counter (OTC) drugs, and supplements you are taking before taking Relpax.
Health conditions
Underlying health conditions can also affect clearance:
- Liver impairment may slow metabolism
- Heart problems, such as coronary artery disease increase safety concerns
- Peripheral vascular disease or ischemic bowel disease raises the risk of vasospasm
Relpax is not recommended for people with a history of heart attack, transient ischemic attack, or certain types of migraine, such as basilar migraine or hemiplegic migraine.
Other risk factors
Age, body composition, family history of heart disease, high blood pressure, high cholesterol, and smoking can all influence how safely eletriptan is processed and tolerated.
Relpax Compared With Other Triptans
Relpax is similar to other triptans such as:
Some triptans have shorter half-lives, while others last longer. Eletriptan’s moderate half-life makes it effective for many migraine attacks while limiting prolonged exposure.
Side Effects and How Long They May Last
Common side effects of Relpax may include:
- Drowsiness
- Dizziness
- Stomach pain
- Fatigue
- Chest discomfort
These side effects usually resolve as the medication leaves the system, often within several hours.
Serious side effects, though rare, can include chest pain, shortness of breath, vasospasm, or signs of heart problems. These can be life-threatening and require immediate medical attention, even if the dose was taken earlier.
Serotonin Syndrome and Drug Timing
Because eletriptan affects serotonin receptors, taking it with antidepressants such as SSRIs or SNRIs can increase the risk of serotonin syndrome. Symptoms may include agitation, rapid heart rate, sweating, confusion, or muscle stiffness.
While the risk is low, it is most relevant during the time Relpax is active in the body, generally within the same 24-hour period.
Relpax, Breastfeeding, and Clearance
Small amounts of eletriptan may pass into breast milk. Because the medication is mostly cleared within 24 hours, some healthcare professionals recommend waiting a full day after a dose before breastfeeding, depending on individual circumstances.
A healthcare provider can offer guidance tailored to your situation.
Medication Overuse Headaches
Using Relpax or other triptans too frequently can lead to medication overuse headaches. Even though eletriptan leaves the body quickly, repeated use over short periods can increase headache frequency.
Relpax is intended for occasional use, not daily migraine management.
When to Talk to a Healthcare Provider
You should seek medical advice if:
- You need frequent doses for migraine attacks
- Relief does not occur after the first dose
- You experience chest pain, shortness of breath, or severe side effects
- You take interacting medications or supplements
A healthcare professional may adjust your migraine treatment plan or recommend preventive options.
Bottom Line
Relpax has a half-life of about 4 hours, and most of the medication leaves your system within 24 hours. While its migraine-relieving effects are relatively short, drug interactions and health conditions can affect how long eletriptan stays active. Always follow dosing instructions and consult a healthcare provider if you have concerns about safety or effectiveness.
FAQs
How long does Relpax stay in your system?
Relpax is mostly cleared from the body within about 24 hours due to its 4-hour half-life. Small amounts may remain longer, but they are usually not clinically significant.
Can I take another migraine medication after Relpax?
Some medications, including ergotamine and dihydroergotamine, should not be taken within 24 hours of Relpax. A healthcare provider can help you time migraine treatments safely.
Why can’t Relpax be taken with certain drugs?
Some drugs slow the breakdown of eletriptan, increasing the risk of serious side effects like heart problems or serotonin syndrome. That’s why spacing doses and avoiding interactions is important.
Does Relpax show up on drug tests?
Relpax is not a controlled substance and is not typically screened for on standard drug tests. Its short duration in the body also makes detection unlikely.
Sources
- Eletriptan hydrobromide tablet, film-coated [package insert]. Zydus Pharmaceuticals USA, Inc. DailyMed. Last updated 9/2023. Accessed Jan. 29, 2026.