Naratriptan is a serotonin receptor agonist from the group of triptans, and is used as a drug in the acute treatment of migraine and in the prevention of cluster headaches. Naratriptan was developed by Glaxo Smith Kline and is the weakest in the current dose of triptan. According to preparations when naratriptan is compared with other triptans, it has the lowest side effects.
Naratriptan is, in Europe, the only material from the group of triptans, in the small package size of up to 2 tablets of 2.5mg per medical prescription. Non-prescription OTC medicines are distributed by Glaxo Smith Kline. The prescription package sizes (more than 2 tablets) are distributed in Germany by Schwarz Pharma.
The onset of action is within an hour and its maximum is four hours. In general, the headache can be felt after one hour. Peak plasma levels are reached within 2 – 3 hours, which is not associated with the onset of action.
Mechanism of action
Naratriptan is a selective agonist of the serotonin receptors 5-HT1B and 5-HT1D, on cerebral blood vessels, which occur pre-synaptically on neurons. Activation of these receptors by sumatriptan during a migraine attack, lead to a constriction of cerebral blood vessels dilating and the other to a reduction in the release of inflammatory mediators.
One of the most characteristic, though rare side effects of the use of naratriptan is angina pectoris, a similar pressure and feeling of oppression of the chest, which is attributed to a constriction of the coronary vessels. An increase in blood pressure can also be observed in some patients. In studies, these side effects with the currently marketed dose of 2.5mg were not more frequent than placebo, so the prescription was for packages of up to 2mg tablets, lifted to 2.5mg.
Naratriptan should not be used in combination with ergotamine, because there is an increased risk of coronary spasm.
The U.S Food warns of the potentially life-threatening interaction of the serotonin syndrome (the body accumulates too much serotonin in the nervous system) while taking a triptan and an antidepressant from the group of SSRIs (Selective serotonin reuptake inhibitors) or SNRIs (selective serotonin and norepinephrine reuptake inhibitors ), if triptans are taken with an SSRI or a SNRI.
Symptoms of serotonin syndrome may be restlessness, hallucinations, loss of coordination, fast heart rate, blood pressure, increased body temperature, which include enhanced reflexes, nausea, vomiting and diarrhoea.