Sumatriptan: a selective 5-hydroxytryptamine receptor agonist for the acute treatment of migraine

Evaluation of sex differences in the pharmacokinetics of oral sumatriptan in healthy Korean subjects using population pharmacokinetic modeling

Sumatriptan was introduced in 1983, as the first of the triptans, selective 5‐hydroxytryptamine (5‐HT_1B/1D) receptor agonists, to treat moderate to severe migraine. Migraine predominates in females. Although there have been reports of sex differences in migraine‐associated features and pharmacokinetics (PKs) of some triptans, sex differences in the PKs of oral sumatriptan have never been evaluated in Korean. We conducted this study of oral sumatriptan to assess the sex differences in Korean population. Thirty‐eight healthy Korean subjects who participated in two separate clinical studies receiving a single oral dose of 50 mg sumatriptan with the same protocols were included in this analysis. A total of 532 sumatriptan concentration observations were used for a population PK modeling. Validation of final population PK model of sumatriptan was performed using bootstrap and visual predictive check. The PK profile of oral sumatriptan was adequately described by a one‐compartmental model with combined transit compartment model and a first‐order absorption. The covariate analysis showed that the clearance of oral sumatriptan was significantly higher in males than in females (male: 444 L/h, female: 281 L/h). Our results showed that there were sex differences in the clearance of oral sumatriptan. These results encourage further studies to establish the sumatriptan pharmacokinetic–pharmacodynamic model considering sex‐related PK differences, which may help to determine optimal dosing regimens for effective treatment of migraine in males and females. Clinical trial registration: CRIS Registration No. KCT0001784.

Sumatriptan-naproxen fixed combination for acute treatment of migraine: a critical appraisal

Nonsteroidal anti-inflammatory drugs (NSAIDs), including naproxen and naproxen sodium, are effective yet nonspecific analgesic and anti-inflammatory drugs, which work for a variety of pain and inflammatory syndromes, including migraine. In migraine, their analgesic effect helps relieve the headache, while their anti-inflammatory effect decreases the neurogenic inflammation in the trigeminal ganglion. This is the hypothesized mechanism by which they prevent the development of central sensitization. Triptans, including sumatriptan, work early in the migraine process at the trigeminovascular unit as agonists of the serotonin receptors (5-HT receptors) 1B and 1D. They block vasoconstriction and block transmission of signals to the trigeminal nucleus and thus prevent peripheral sensitization. Therefore, combining these two drugs is an attractive modality for the abortive treatment of migraine. Sumatriptan-naproxen fixed combination tablet (Treximet [sumatriptan-naproxen]) proves to be an effective and well tolerated drug that combines these two mechanisms; yet is far from being the ultimate in migraine abortive therapy, and further research remains essential.

Permeation of sumatriptan through human vaginal and buccal mucosa

Continued interest in the various routes by which sumatriptan may be administered prompted us to investigate its passage through buccal mucosa. Because human buccal mucosa is scarce, we proposed using the relatively abundant vaginal mucosa, which has been shown to have comparable diffusion rates for a number of widely varying molecules, as a model of buccal mucosa. In addition, by comparing these two tissues with respect to their permeability to sumatriptan, the human vaginal/buccal mucosa model could be further evaluated. Clinically healthy human vaginal and buccal mucosa specimens were used in the permeability studies. Permeability to sumatriptan was determined using a continuous flow-through diffusion system in the presence and absence of permeation enhancers. No statistically significant differences in permeability could be demonstrated for both mucosae toward sumatriptan. Flux values obtained in the absence and presence of glycodeoxycholate and lauric acid (1:1 molar ratio) to sumatriptan of buccal and vaginal mucosa, respectively, were not significantly different. The results obtained further support the hypothesis of the vaginal/buccal mucosal in vitro permeability model and suggest that this model may be used in conjunction with various absorption enhancers. Further studies on the buccal route of absorption of sumatriptan are thus warranted.

Pregnancy outcome following prescription for sumatriptan

BACKGROUND

Some 2.5% of fertile Danish women use sumatriptan, and the drug is also taken during pregnancy. Although sumatriptan reacts selectively in brain vessels, the possibility of reactions with placental blood flow and uterotonic activity cannot be ruled out. The aim of our study was to examine the association between sumatriptan exposure during pregnancy and the risk of preterm delivery and low birth weight.

METHODS

Data from the Pharmaco-Epidemiological Prescription Database of North Jutland county regarding all women who had given birth in the county of North Jutland from 1991 to 1996 were linked to the Danish Medical Birth Registry. Women who were exposed to sumatriptan during pregnancy were identified (n = 34), and using logistic regression models their pregnancy outcome was compared with two groups of pregnant women: (1) healthy women (n = 15 955) and (2) migraine controls (n = 89), defined as migraine patients who did not redeem prescriptions for migraine treatment during pregnancy.

RESULTS

The risk of preterm delivery was elevated among women exposed to sumatriptan compared with migraine controls (odds ratio [OR] 6.3, 95% confidence interval [CI] 1.2-32.0) and healthy women (OR 3.3, 95% CI 1.3-8.5). The odds ratio for having a newborn with a low birth weight was increased (OR 3.0, 95% CI 1.3-7.0) for all migraine patients who delivered at term (n=115) compared with the outcome of healthy pregnancies.

CONCLUSIONS

We found that sumatriptan exposure during pregnancy was associated with an increased risk of preterm delivery and low birth weight. These findings may be due to drug exposure, but they may also reflect the impact of disease severity rather than the treatment itself, or confounding, or chance.

Distribution and excretion of sumatriptan in human milk

1. The excretion of a 6 mg subcutaneous dose of sumatriptan in breast milk was studied in five lactating volunteer subjects with a mean age of 27.6 years and a mean body weight of 75 kg. Drug concentrations in milk and plasma over the ensuing 8 h were measured by high-performance liquid chromatography. 2. The mean milk:plasma ratio estimated from the areas under the milk and plasma concentration-time curves (AUC) was 4.9 (95% CI 4.1-5.7), indicating a significant transfer of sumatriptan into the milk compartment. 3. The mean total recovery of drug in milk was estimated to be only 14.4 micrograms (95% CI 6.1-22.7 micrograms), or 0.24% of the 6 mg administered dose. On a weight-adjusted basis this corresponded to a mean infant exposure of 3.5% of the maternal dose (95% CI 0.3-6.7%). 4. If oral bioavailability in the infant is similar to that in adults (14%), the weight-adjusted infant dose is reduced to 0.49%. Furthermore, allowance for reduced clearance in the infant predicts an infant exposure varying from 4.9% in a very premature neonate to 0.7% in a 30 week old infant. 5. Since sumatriptan is usually administered as a single dose at infrequent intervals, the low level of excretion in breast milk suggests that continued breast feeding following its use will not pose a significant risk to the suckling infant. Even this minor exposure could be largely avoided by expressing and discarding all milk for 8 h after the dose.

Recent Advances in the Understanding and Treatment of Migraine

Migraine is a disorder that afflicts more than 23 million individuals in the United States alone. The disorder is characterized by paroxysmally recurring attacks, which are moderately to severely disabling. The migraine attack is typified by a severe, usually unilateral headache, which is pulsatile in quality, and by one or more concomitant symptoms, such as nausea, vomiting, photophobia, and/or phonophobia. Because of its debilitating nature, migraine causes significant morbidity among sufferers, including lost time from work or school, and inability to perform other normal daily activities during attacks. The precise pathogenesis of migraine remains to be elucidated. However, the attack may be initiated and perpetuated by both neural and vascular mechanisms. The trigeminovascular system appears to be particularly involved. Treatment of migraine consists of avoidance of trigger factors, acute or abortive pharmacotherapy, and prophylactic pharmacotherapy. A plethora of endogenous and exogenous migraine triggers have been identified, some of which can be avoided or controlled in order to reduce attack frequency. The ergots represent the accepted standard for the treatment of the acute attack, though significant toxicity and the potential for rebound headache with overuse limit the usefulness of these agents. Simple and combination analgesics are also limited by their inherent propensity to cause a rebound phenomenon when overused. Sumatriptan is a selective serotonin receptor agonist that is now available for abortive treatment of migraine. It has been shown to be highly effective in treating the acute attack. Beta-blocking drugs are the agents of choice for migraine prophylaxis, though anti-depressant compounds, calcium channel antagonists, non-steroidal anti-inflammatory drugs, cyproheptadine, and methysergide are also used. Non-pharmacological therapy may be tried, but is rarely effective by itself.

Cerebral circulatory changes during migraine headache with aura

Many authors report alterations of cephalic (both intracranial and extracranial) blood flow and vascular responsiveness in patients with migraine. In the majority of reports, rCBF has been decreased during the prodromal phase and increased during and immediately after the headache phase of migraine attacks. Abnormal vascular responsiveness has been demonstrated, not only during each attack, but also between attacks. Pharmacological and therapeutic evidence that many vasoactive agents induce, prevent or abolish attacks of migraine headache are consonant with the close relationships that exist between vascular abnormalities and the pathogenesis of migraine with aura. This is particularly true of the marked therapeutic effectiveness of calcium entry blockers, which are effective in the prophylaxis of migraine, and sumatriptan, which has direct vasoconstrictive effects, with relief of the headache, which lends strong support to a vascular hypothesis.