Triptans
Examples
- Sumatriptan
- Rizatriptan
- Zolmitriptan
Indications
Relief of migraine headaches - particularly when standard analgesia such as paracetamol or NSAIDs have failed. They are not indicated in hemiplegic, basilar or ophthalmoplegic migraine.
Contraindications
Contraindications
- Ischaemic Heart Disease and coronary vasospasm
- Previous MI or TIA/CVA
- Uncontrolled or moderate/severe hypertension
- Peripheral vascular disease
Caution
- The elderly (not licensed for use in the elderly)
- Conditions which predispose to coronary artery disease
- Patients with history of seizures
- Mild controlled hypertension
Caution is also recommended in the use of Sumaitriptan in patients with sensitivity to sulfonamides.
Mechanism
Triptans are known to act as agonists on 5-HT (5-hydroxytryptamine, also known as serotonin).
The pathophysiology behind migraines is still not completely understood. One theory is that 5-HT (serotonin) stimulates the vascular endothelium to release nitric oxide, causing vasodilation with stimulation of meningeal sensory nerve endings.
Triptans are 5-HT1D receptor agonists and therefore block the receptors so 5-HT is unable to bind to the receptor on the vascular endothelium.
Administration
Oral.
In addition, Sumatriptan and Zolmitriptan can both be given as a nasal spray, and Sumatriptan can be given as a subcutaneous injection. This may be useful as one common symptom of migraine is nausea / vomiting.
Adverse Reactions
The more common side effects of triptans include:
- Sensations of tingling, heat, pressure or tightness in any part of the body.
- Dizziness
- Weakness
- Fatigue
- Nausea and vomiting
- Drowsiness
In addition to these, slightly less common, but significant side effects include:
- Dyspepsia
- Abdominal Pain
- Tachycardia
- Myalgia
As with other anti-migraine drugs (e.g. analgesics), triptans may cause "medication overuse headache".
Interactions
Extreme care should be given when prescribing Triptans to patients who are on Selective Serotonin Reuptake Inhibitors (SSRIs). The combination of the two drugs can lead to a very dangerous, life-threatening condition known as Serotonin Syndrome.
Other drugs which can interact with triptans to cause increased levels of serotonin in the brain include:
- Lithium
- Monoamine Oxidase Inhibitors (like SSRI, these are used to treat depression)
Education
Patients should understand that triptans are to be used only when a migraine is underway, and they are not to be used as a preventative method (unless specifically directed by a specialist). Best results are achieved when the triptan is administered once the patient starts to feel mild discomfort, and not in the earlier aura stage. Patients should not use their triptan regularly as they run the risk of an analgesia induced headache.
Patients should be warned that they should only use one dose per migraine attack. If the patient dose not respond then a second dose should not be taken. However if the patient does respond and the migraine recurs, then the patient may take a second dose provided that it has been at least 2 hours since the first dose.
Patients should also be advised that the best approach to treating migraines is multi-factorial, and not simply through prescribing triptans. As mentioned, NSAIDs and paracetamol may have a role to play, particularly in less severe migraines, but there are also important non-pharmalogical interventions such as identification and avoidance of triggering factors.
Pharmacokinetics
Nil relevant.
