Why does Imitrex (sumatriptan) make me feel weird?
Imitrex (sumatriptan) can cause a variety of side effects, which may make you feel weird after taking it. Side effects you experience from Imitrex can depend on which dosage form you’re taking. It is not fully understood what causes these side effects, but some could be related to how Imitrex affects blood vessels and nerves.
Rare side effects that can occur from taking any form of Imitrex include abnormal heart rhythm, vision loss, high blood pressure, seizures, and tightness in the chest, throat, neck, or jaw. If you are having severe symptoms, such as trouble breathing or hives, get medical attention right away.
Side effects of Imitrex nasal spray
Imitrex nasal spray is available in 5 mg, 10 mg, and 20 mg strengths. The following side effects were reported during clinical studies of Imitrex nasal spray:
- Bad or unusual taste: 13.5% to 24.5%
- Nausea and/or vomiting: 11% to 13.5%
- Nasal discomfort: 2.5% to 3.8%
- Throat discomfort: 0.8% to 2.4%
- Dizziness or vertigo: 1% to 1.7%
Imitrex nasal spray can also cause local irritation in the nose, including burning, numbness, discharge, and pain. These side effects usually go away within 2 hours.
Side effects of Imitrex injection
Imitrex injection is available in 4 mg and 6 mg strengths. The following side effects were reported during clinical studies of Imitrex 6 mg injection:
- Injection site reaction: 59%
- Tingling: 14%
- Dizziness or vertigo: 12%
- Warm or hot sensation: 11%
- Burning sensation: 7%
- Feeling of heaviness: 7%
- Pressure sensation: 7%
- Flushing: 7%
- Feeling of tightness: 5%
- Chest discomfort: 5%
- Weakness: 5%
- Neck pain: 5%
- Numbness: 5%
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Side effects of Imitrex tablets
Imitrex tablets come in 25 mg, 50 mg, and 100 mg strengths. The following side effects were reported during clinical studies of Imitrex tablets:
- Pain and pressure sensations: 6% to 8%
- Tingling: 3% to 5%
Tell your prescriber if you are experiencing bothersome side effects from Imitrex. They may be able to lower your dose or suggest ways to manage them.
Managing and minimizing side effects
If feeling “weird” after Imitrex is persistent or bothersome:
- Track symptoms and timing using a diary to help identify triggers and patterns.
- Discuss dose adjustments and alternate delivery methods with a healthcare provider; tablets generally have milder effects than nasal sprays or injections.
- Avoid combining sumatriptan with certain antidepressants (SSRIs/SNRIs) without medical approval.
- Seek urgent care if you experience trouble breathing, severe chest pressure, irregular heartbeat, or visual loss.
This is not all the information you need to know about Imitrex (sumatriptan) for safe and effective use and does not take the place of your healthcare provider’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.
References
- Imitrex - sumatriptan injection [package insert]. Updated February 2023. GlaxoSmithKline LLC. Accessed July 24, 2024 at https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fee7d073-0b99-48f2-7985-0d8cf970894b
- Imitrex - sumatriptan spray [package insert]. Updated March 2024. GlaxoSmithKline LLC. Accessed July 24, 2024 at https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=cc11b09d-e6cc-4cf8-1495-5ac64d5aae5f
- Imitrex - sumatriptan tablet [package insert]. Updated February 2024. GlaxoSmithKline LLC. Accessed July 24, 2024 at https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=584abe73-8290-4484-ff8e-5890831c095e
- National Health Service. (n.d.). Side effects of sumatriptan. NHS. Accessed on September 4, 2025 from https://www.nhs.uk/medicines/sumatriptan/side-effects-of-sumatriptan/
Read next
Ubrelvy vs Imitrex (sumatriptan): How do they compare?
Ubrelvy and Imitrex are both oral tablets used to treat migraine, but there are differences in the way they work. Ubrelvy prevents a protein called CGRP thought to play a role in migraine attacks from binding to its receptor and Imitrex is thought to bind to serotonin 5‑HT1B/1D receptors, and inhibit pro-inflammatory substances Although no head-to-head comparison trials compare Ubrelvy to Imitrex, indirect evidence suggests that overall, Ubrelvy is no more effective, and may be inferior to Imitrex at relieving migraine in adults who are able to tolerate triptans. For those adults with moderate-to-severe migraine attacks that cannot tolerate triptans or who have found them ineffective, Ubrelvy is beneficial for treating migraines compared to no treatment. Ubrelvy is associated with fewer side effects than Imitrex, but is more expensive, costing almost twice as much. Continue reading
How long does Imitrex (sumatriptan) take to work?
Imitex (sumatriptan) can start to work within 10-30 minutes of taking a dose, depending on the formulation. However, it may take a few hours for you to notice the full effects.
Continue reading
Can Imitrex (sumatriptan) cause rebound headaches?
Yes, Imitrex (sumatriptan) can cause rebound headaches (also known as medication-overuse headaches). Rebound headaches are more likely to occur if you take Imitrex alone or a combination of Imitrex and other headache medications (e.g., opioids, analgesics) for 10 or more days per month. Continue reading
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