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Papers of the Week

Papers: 3 Aug 2019 - 9 Aug 2019

Pharmacology/Drug Development


2019 Nov

Br J Clin Pharmacol



Why is the therapeutic effect of acute antimigraine drugs delayed? A review of controlled trials and hypotheses about the delay of effect.


In randomised, controlled trials (RCTs) of oral drug treatment of migraine attacks, efficacy is evaluated after 2 hours. The effect of oral naratriptan 2.5 mg with a maximum blood concentration (T ) at 2 hours increases from 2 to 4 hours in RCTs. To check whether such a delayed effect is also present for other oral antimigraine drugs, we hand-searched the literature for publications on RCTs reporting efficacy. Two triptans, three non-steroidal anti-inflammatory drugs (NSAIDs), a triptan combined with an NSAID, and a calcitonin gene-related peptide receptor antagonist were evaluated for their therapeutic gain with determination of time to maximum effect (E ). E was compared with known T from pharmacokinetic studies to estimate the delay to pain-free. The delay in therapeutic gain varied from 1-2 hours for zolmitriptan 5 mg to 7 hours for naproxen 500 mg. An increase in effect from 2 to 4 hours was observed after eletriptan 40 mg, frovatriptan 2.5 mg, and lasmiditan 200 mg, and after rizatriptan 10 mg (T = 1 h) from 1 to 2 hours. This strongly indicates a general delay of effect in oral antimigraine drugs. A review of five possible effects of triptans on the trigemino-vascular system did not yield a simple explanation for the delay. In addition, E for triptans probably depends partly on the rise in plasma levels and not only on its maximum. The most likely explanation for the delay in effect is that a complex "antimigraine system" with more than one site of action is involved.