Rizatriptan

Additional information

Rizatriptan is used to treat acute migraine attacks [1].Migraine is almost twice as common in women as in men [2, 3]. In a Swedish population- based study the one-year prevalence was 16.7 % in women and 9.5 % in men [4] which is slightly lower than three months prevalence reported from the US [2]. Another indication for (parenteral) triptans is cluster headache [5]. This is a trigeminal autonomic cephalgia with very painful, unilateral and short-lasting headache attacks. Cluster headache is rare with an estimated prevalence of 0.1%. In contrast to migraine, cluster headache is more common in men than in women [5]. The men-women ratio has recently been estimated to 2.5, older studies show a more pronounced male risk [6]. Smoking is a risk factor for cluster headache and the increased risk in women has been associated with more smoking in women [5, 6].

Pharmacokinetics and dosing

The pharmacokinetics of single oral doses of rizatriptan 2.5-15 mg administrated to healthy volunteers was studied in a randomized, crossover study (12 men, 12 women). The mean AUC of oral rizatriptan was 19-35% higher in women than in men. However, the difference is not likely to be of clinical relevance. Plasma clearance of rizatriptan was about 25% higher in men than in women. No difference in the dose-effect relationship between men and women was noted [7]. In another study (6 men, 6 women), where healthy volunteers received a single dose rizatriptan 10 mg, half-life was longer in men. Other pharmacokinetic parameters showed no sex differences [8, 9]. No pharmacokinetic differences between elderly men and women have been found [10].

Effects

The efficacy of rizatriptan 5 mg in adolescents (12-17 years old) was established in two randomized, placebo-controlled trials (212 men, 263 women). Rizatriptan 5 mg was shown to be more effective than standard care (patient’s usual migraine therapy) during long-term use (over 1 year). Treatment effects for pain relief were not dependent on patient’s sex [11].

Time to pain freedom in acute migraine with rizatriptan 10 mg was compared to standard care in a prospective, open-label study (197 men, 1292 women; mean age 41.7 years). There were no significant differences in time to pain freedom between men and women [12].

Results from randomized, double-blind studies of migraineurs (66 men, 280 women) show no sex differences in response to frovatriptan 2.5 mg, rizatriptan 10 mg, zolmitriptan 2.5 mg or almotriptan 12.5 mg [13].

Adverse effects

According to trials performed by the pharmaceutical company, incidence of adverse reactions did not differ between men and women [1].

Reproductive health issues

Regarding teratogenic aspects, please consult Janusmed Drugs and Birth Defects (in Swedish, Janusmed fosterpåverkan).