1. Clinical Overview
Almotriptan malate is a selective serotonin (5-HT1B/1D) receptor agonist (triptan) used for the acute treatment of migraine with or without aura in adults. It is a second-generation triptan with high oral bioavailability and a favorable tolerability profile, often associated with a lower incidence of chest symptoms compared to some other triptans. It is effective in relieving migraine pain, photophobia, phonophobia, and nausea.
| Onset | Duration | Bioavailability |
|---|---|---|
| Pain relief can begin within 30 minutes to 2 hours post-dose. | The therapeutic effect typically lasts for 24 hours, preventing headache recurrence. | Approximately 70-80%. |
2. Mechanism of Action
Almotriptan exerts its therapeutic effects by binding with high affinity to serotonin 5-HT1B and 5-HT1D receptors located on intracranial blood vessels and sensory nerve terminals of the trigeminal system. This dual action causes cranial vasoconstriction of dilated vessels and inhibits the release of pro-inflammatory neuropeptides (like CGRP and substance P) from perivascular trigeminal nerves, thereby reducing neurogenic inflammation and pain transmission.
3. Indications & Uses
- Acute treatment of migraine with aura in adults
- Acute treatment of migraine without aura in adults
4. Dosage & Administration
Adult Dosage: 6.25mg to 12.5mg as a single dose at the onset of migraine. If headache recurs, a second dose may be taken after 2 hours. Maximum: 25mg in 24 hours. 6.25mg is often the recommended starting dose.
Administration: Take orally with or without food at the earliest sign of a migraine headache. Tablet should be swallowed whole with a glass of water. Do not crush or chew. If no response to the first dose, do not take a second dose for the same attack. Do not use for more than 10 headache days per month to avoid medication-overuse headache.
5. Side Effects
Common side effects may include:
- Dizziness
- Somnolence (drowsiness)
- Nausea
- Dry mouth
- Paresthesia (tingling sensation)
- Fatigue
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| MAO-A Inhibitors (Moclobemide, Clorgyline) | Markedly increased almotriptan plasma levels (up to 4-fold) due to inhibited metabolism. Risk of serotonin syndrome. | Contraindicated |
| Potent CYP3A4 Inhibitors (Ketoconazole, Itraconazole, Ritonavir, Clarithromycin) | Increased almotriptan plasma AUC. Dose should not exceed 6.25mg in 24 hours. | Major |
| Other 5-HT1 Agonists (Triptans) or Ergot Derivatives (Ergotamine, Dihydroergotamine) | Increased risk of vasospastic reactions. A 24-hour separation is recommended. | Major |
| SSRIs/SNRIs (e.g., Sertraline, Fluoxetine, Venlafaxine) | Potential increased risk of serotonin syndrome (weakness, hyperreflexia, incoordination). | Moderate |
| Propranolol | Increases almotriptan AUC by ~20%. No dose adjustment needed. | Minor |
7. Patient Counselling
- DO take at the first sign of a migraine headache.
- DO NOT use for more than 10 days per month to avoid medication-overuse headaches.
- DO NOT take a second dose for the same attack if the first dose fails, but you may take it for a recurrence after 2 hours.
- DO NOT take concurrently with other triptans or ergot medications.
- DO inform your doctor if you are pregnant, planning pregnancy, or breastfeeding.
- DO inform your doctor about all other medicines you take, including over-the-counter drugs and herbal supplements.
8. Toxicology & Storage
Overdose: Symptoms may include hypertension, cardiovascular events, drowsiness, seizures, and serotonin syndrome. In clinical trials, doses up to 200mg have been administered without severe adverse events.
Storage: Store below 30°C. Protect from light and moisture. Keep out of reach of children.