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244 Migraine and undifferentiated headache
There is a limited acute care role for the ergot derivative dihydroergot-
amine (DHE). Trials show that the nasal spray formulation (2 mg IN) provides
MH relief that is better than placebo but inferior to that achieved with either
antiemetics or triptans. 3,5–7
Years ago, routine MH care included antiemetic pretreatment to prevent
nausea induced by the ergots. Clinicians noted that MH pain was often
alleviated before the “real” analgesic was administered, prompting interest
in the use of antiemetics as stand-alone therapy. 7,8 Among the antiemetics
RCT data show to be highly effective for MH are metoclopramide (10 mg IV)
and prochlorperazine (10 mg IV). 9,10 Prochlorperazine is more sedating than
metoclopramide, which may be related to the higher success seen with the
former. 11,12 Metoclopramide remains quite useful, however, being demonstratedly
more effective than the opioid meperidine (pethidine) in patients
with undifferentiated headaches. 13
Prochlorperazine’s superiority over other antiemetics is also found for non-
IV administration routes. However, some patients may lack IV access, and
migraineurs’ frequent nausea limits the utility of PO medications.
Administration of 10 mg prochlorperazine by either IM or PR suppository
provides at least partial relief of MH. 11,14–16 An additional route of administration
for prochlorperazine is the orally disintegrating buccal tablet (3 mg
dose). A small study evaluating the use of this preparation for MH showed
promising results. 17 Trials involving IM and PR metoclopramide formulations
have failed to demonstrate superiority of either approach over placebo. 11,18
One of the advantages of the antiemetics is their efficacy in a broad range of
benign headache syndromes. As noted in this chapter’s introduction, precise
differentiation between benign tension and vascular headache syndromes
tends to be both difficult and unnecessary. 1,2 Previous ED investigators
have reported efficacy of metoclopramide and prochlorperazine in a variety
of headache syndromes (including undifferentiated cephalalgia). 13,15,16
The phenothiazine chlorpromazine, one of the earliest agents assessed for
headache treatment, has been rendered obsolete by the emergence of other
options for ED treatment of MH. Chlorpromazine (12.5 mg IV) is efficacious,
but its administration is associated with a high incidence of untoward side
effects (e.g. hypotension, deep sedation, extrapyramidal reactions). 19,20