Triptans: do they differ?

Rescue therapy for acute migraine, part 1: triptans, dihydroergotamine, and magnesium

OBJECTIVE

To review and analyze published reports on the acute treatment of migraine headache with triptans, dihydroergotamine (DHE), and magnesium in emergency department, urgent care, and headache clinic settings.

METHODS

MEDLINE was searched using the terms "migraine" and "emergency," and "therapy" or "treatment." Reports from emergency department and urgent care settings that involved all routes of medication delivery were included. Reports from headache clinic settings were included only if medications were delivered by a parenteral route.

RESULTS

Acute rescue treatment studies involving the triptans were available for injectable and nasal sumatriptan, as well as rizatriptan. Effectiveness varied widely, even when the pain-free and pain-relief statistics were evaluated separately. As these medications are known to work best early in the migraine, part of this variability may be attributed to the timing of triptan administration. Multiple studies compared triptans with anti-emetics, dopamine antagonists, and non-steroidal anti-inflammatory drugs. The overall percentage of patients with pain relief after taking sumatriptan was roughly equivalent to that recorded with droperidol and prochlorperazine. Sumatriptan was equivalent to DHE when only paired comparisons were performed. While the data extracted suggest that magnesium may be effective in treating all symptoms in patients experiencing migraine with aura across all migraine patients, its effectiveness seems to be limited to treating only photophobia and phonophobia.

CONCLUSIONS

Although there are relatively few studies involving health-care provider-administered triptans or DHE for acute rescue, they appear to be equivalent to the dopamine antagonists for migraine pain relief. The relatively rare inclusion of a placebo arm and the frequent use of combination medications in active treatment arms complicate the comparison of single agents with each other.

Pharmacokinetic profile of a new form of sumatriptan tablets in healthy volunteers

OBJECTIVE

Rapid delivery of migraine-specific medication to its site(s) of action is thought to be crucial in preventing or minimizing sensitization of central pain pathways and thereby in optimizing pain-free outcomes in patients with migraine. Sumatriptan has been developed as a new tablet formulation to enhance the rate of systemic drug delivery by improving tablet disintegration and drug dispersion relative to those of conventional tablets. These enhanced formulation characteristics may be beneficial during occurrences of the gastric stasis that can accompany migraine.

METHODS

This randomized, open-label, 4-way crossover study (n = 32) was conducted to determine whether the new formulation of sumatriptan 50 and 100 mg is bioequivalent to sumatriptan conventional tablets and to compare the pharmacokinetic profiles of the new formulation and the conventional tablet during the early (0-2 h) postdose interval in healthy volunteers. Pharmacokinetics during the early post-dose interval are important in determining a drug's onset of action, an important parameter to patients with migraine.

RESULTS

The results confirm that the new formulation of sumatriptan and sumatriptan conventional tablets are bioequivalent as demonstrated by the finding that the 90% confidence intervals for the sumatriptan area under the concentration time curve to infinity and to the last evaluable time point (AUC(0- infinity ) and AUC(0-t), respectively) and maximum plasma concentration (C(max)) fell within the predetermined bounds defining bioequivalence (0.80-1.25) for both doses. Pharmacokinetic parameters measured early (0-2 h) after dosing reveal slightly faster absorption, on average, of the new sumatriptan formulation than sumatriptan conventional tablets although high intersubject variability was observed. For the new sumatriptan formulation, AUC(0-2) (AUC up to 2 h post dose) was, on average, 1% greater (50 mg) and 8% greater (100 mg) and maximal sumatriptan levels were attained, on average, 10 min earlier (50 mg) and 15 min earlier (100 mg) compared with the conventional tablet. Other measures including AUC(0-0.5) (AUC to 30 min post-dose), times to achieve sumatriptan concentrations of 5 and 10 ng/mL, and mean percentage C(max) 15, 20 and 30 min post-dose demonstrate an observable improvement in rate of drug absorption for the new form of sumatriptan compared with conventional tablets.

CONCLUSION

The new form of sumatriptan is bioequivalent to sumatriptan conventional tablets and is absorbed more quickly than conventional tablets.

Newer formulations of the triptans: advances in migraine management

Migraine is a common, frequently incapacitating, headache disorder that imposes a substantial burden on both the individual patient and society. The last two decades have witnessed an explosion in our understanding of the pathophysiology of migraine, and in our development of an efficacious and diverse therapeutic armamentarium. There are several routes of drug administration available to patients with migraine. All the serotonin 5-HT(1B/1D) receptor agonists (triptans) are available as oral tablets (sumatriptan, rizatriptan, zolmitriptan, naratriptan, almotriptan, frovatriptan and eletriptan). Only sumatriptan is available as a subcutaneous injection. Some triptans are also available via newer routes of administration, including orally disintegrating tablets (rizatriptan and zolmitriptan), rectal suppositories (sumatriptan) and intranasal sprays (sumatriptan and zolmitriptan). Oral disintegrating tablets and other non-oral triptan routes (subcutaneous, intranasal, rectal) are a useful alternative to conventional oral tablets for patients who have difficulty swallowing pills or prefer not to do so, and for patients whose nausea and/or vomiting precludes swallowing tablets and/or makes the likelihood of complete absorption unpredictable. This is important because epidemiological studies in migraine reveal that the vast majority of patients (>90%) have experienced nausea during a migraine attack and more than 50% have nausea with the majority of attacks. Similarly, most (almost 70%) have vomited at some time during an attack and of these patients, almost one-third vomit in the majority of attacks. The newer formulations, rapidly dissolving tablets and intranasal sprays, afford patients the opportunity to use abortive therapy without the need for liquids, at anytime and anywhere, at the onset of a migraine attack. Furthermore, the intranasal sprays are absorbed rapidly and have a prompt onset of action allowing for significant pain free rates versus placebo as early as 15 minutes post administration. The ability to administer treatment early in a migraine attack and have a rapid onset of action is particularly important in acute migraine treatment in order to prevent the development of central sensitisation. While many patients and physicians choose conventional oral tablets because of familiarity and ease of administration, the newer formulations, oral disintegrating tablets and intranasal sprays, should be given consideration as first-line agents in selected patients.