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•Prescrire International Special Edition 2015/Volume 24 N°158
A
M
igraine is characterised by recur-
rent headache. The clinical pic-
ture is usually fairly typical, dispensing
with the need for diagnostic tests (1,2).
Typical
symptoms.
Migraine headaches are usu-
ally unilateral and pulsating,
accompanied by nausea, vomiting,
photophobia and phonophobia. They
usually last from 4 to 72 hours (1).
About 20% of migraine patients
experience transient neurological
symptoms (visual, sensory, etc.),
generally lasting less than an hour,
prior to the onset of headache (1,2).
Sometimes debilitating
but not life-threatening.
Migraine is not associated
with life-threatening complications.
Women with migraine probably have
a slightly higher risk of stroke, partic-
ularly if they use oral contraceptives
(1,3). The frequency of migraine
attacks varies from one patient to
another but is usually between 1 and
4 per month. Patients are symptom-
free between attacks (1,2). Migraine
attacks sometimes have a debilitating
impact on family, social or professional
life (1).
Identify triggers.
Prevention
of migraine attacks begins by
examining the circumstances
under which they occur. Factors
known to trigger migraine attacks
include too little sleep, stress, smoking,
coffee, wine, fasting and visual stimuli
(1,4). Some women experience
migraine attacks between 2 days before
and 3 days after the onset of menstru
ation (catamenial migraine). Migraine
attacks may become more frequent
around the menopause (1,5). Many
drugs can trigger migraine-like head
aches, including vasodilators (nitrates,
sildenafil
, etc.) and hormonal contra-
ceptives (6,7). Some patients develop
self-sustaining headache, in addition to
their underlying migraine, because of
continuous use of analgesics (7).
Non-drug measures: avoid
triggers.
The best way to pre-
vent migraine attacks is to
avoid triggering factors as much as pos-
sible, as this can help to limit the need
for preventive medication (1). Tech-
niques such as relaxation, feedback and
cognitive-behavioural therapy appear
to be effective in preventing migraine
attacks, although their impact cannot
be precisely quantified. However, their
harm-benefit balance appears to be
favourable, given the absence of note-
worthy adverse effects (1). Acupunc-
ture has not been shown to have any
efficacy in preventing migraine attacks
beyond the placebo effect (8).
Preventive medication:
depending on the degree
of discomfort.
It is import-
ant to inform patients that drugs can
reduce the frequency of migraine
attacks, but that they cannot com-
pletely eliminate them (1).
The decision to use a drug to pre-
vent migraine attacks should be dis-
cussed with the patient, depending
on the frequency and intensity of
attacks and their impact on quality of
life. Potential adverse effects should
be weighed against the likely bene-
fits. Clinical practice guidelines rec-
ommend preventive medication for
patients who experience more than
4 to 8 attacks per month (1).
When the pain associated with
migraine attacks leads to heavy use of
analgesics, preventive medication can
help reduce analgesic consumption (1).
The placebo effect should be taken
into account when initiating or mod-
ifying a preventive treatment: in clin-
ical trials, the monthly frequency of
attacks was halved in about 30% of
patients taking placebo (1).
Propranolol first.
The drug
of first choice for preventing
migraine attacks is oral
pro-
pranolol
, a beta-blocker, at a dose of
120 mg to 240 mg per day, starting
with 40 mg two to three times a day,
and then increasing the dosage each
week if necessary. This treatment
halves the frequency of attacks in
about 60% of patients (1,9).
The adverse effects of beta-blockers
include cardiac disorders, broncho
spasm, exacerbation of Raynaud’s
disease, neuropsychiatric disorders
and gastrointestinal problems (7).
Beta-blockers can cause life-threatening
bronchospasm in patients with asthma
or obstructive airways disease (7).
Co-administration of
propranolol
with ergot derivatives with vasocon-
strictive properties, such as
methysergide
and
dihydroergotamine
(sometimes
used in the treatment of migraine
attacks), can cause arterial spasmwith
ischaemia of the extremities. In prac-
tice, ergot derivatives should not be
prescribed to patients already taking
beta-blockers (1,7).
Propranolol
metab-
olism is slowed by enzyme inhibitors,
which can aggravate dose-dependent
effects (7).
Propranolol
metabolism is
enhanced by some enzyme inducers,
including
nicotine
; as a result, the dose
of
propranolol
may need to be
Translated from
Rev Prescrire
October 2014; 34 (372): 766-768
Prevention of migraine attacks
First-choice treatments
Identifying and avoiding the fac-
tors that trigger migraine attacks can
reduce their frequency and the need
for preventive medication.
Continuous use of analgesics can
trigger attacks.
Preventive medication may be
justified when migraine attacks are
frequent and disabling.
Propranolol
is the drug of first
choice for the prevention of migraine.
Valproic acid
or
amitriptyline
is a
second choice.
Key points
