The majority of
migraine attacks are associated with gastrointestinal symptoms which add considerably to the distress and inconvenience caused by the
headache. When
salicylate absorption from effervescent
aspirin tablets was studied during
migraine, the rate of absorption was found to be reduced relative to that found in non-migrainous volunteers and in the same patients when
headache-free. There is evidence that this reduced rate of absorption is caused by gastrointestinal stasis and reduced rate of gastric emptying. Patients in whom
aspirin absorption was delayed were more likely to take longer to respond and to require additional treatment.
Metoclopramide, which increases gastric emptying rate, has been shown to improve the rate of absorption of
aspirin during
migraine and also increase the rate of recovery from the attack and avoid the need for additional treatment; effects which were not shown by
thiethylperazine. It is likely that delayed absorption during
migraine affects some drugs other than
aspirin, such as
ergotamine, and it is therefore recommended that the most rapidly absorbable formulation should be used. If such treatment is ineffective,
metoclopramide may be a useful addition and should be tried before resorting to other routes of administration.