l PREGNANCY Most manufacturers of antihistamines advise
avoiding their use during pregnancy; however, there is no
evidence of teratogenicity. Use in the latter part of the
third trimester may cause adverse effects in neonates such
as irritability, paradoxical excitability, and tremor.
l BREAST FEEDING Most antihistamines are present in
breast milk in varying amounts; although not known to be
harmful, most manufacturers advise avoiding their use in
mothers who are breast-feeding.
Driving and skilled tasks Drowsiness may affect
performance of skilled tasks (e.g. driving); sedating effects
l MEDICINAL FORMS There can be variation in the licensing of
different medicines containing the same drug. Forms available
from special-order manufacturers include: oral suspension, oral
CAUTIONARY AND ADVISORY LABELS 2
Cyproheptadine hydrochloride 4 mg Periactin 4mg tablets | 30 tablet p £5.99 DT = £5.99
Hydroxyzine hydrochloride 30-Mar-2017
l DRUG ACTION Hydroxyzine is a sedating antihistamine
which exerts its actions by antagonising the effects of
▶ Child 6 months–5 years: 5–15 mg daily in divided doses,
dose adjusted according to weight; maximum 2 mg/kg
▶ Child 6–17 years (body-weight up to 40 kg): Initially
15–25 mg daily in divided doses, dose increased as
necessary, adjusted according to weight; maximum
▶ Child 6–17 years (body-weight 40 kg and above): Initially
15–25 mg daily in divided doses, increased if necessary
to 50–100 mg daily in divided doses, dose adjusted
▶ Adult: Initially 25 mg daily, dose to be taken at night;
increased if necessary to 25 mg 3–4 times a day
▶ Elderly: Initially 25 mg daily, dose to be taken at night;
increased if necessary to 25 mg twice daily
MHRA/CHM ADVICE: RISK OF QT-INTERVAL PROLONGATION AND
TORSADE DE POINTES (APRIL 2015)
Following concerns of heart rhythm abnormalities, the
safety and efficacy of hydroxyzine has been reviewed by
the European Medicines Agency. The review concludes
events are most likely to occur in patients who have risk
factors for QT prolongation, e.g. concomitant use of
drugs that prolong the QT-interval, cardiovascular
disease, family history of sudden cardiac death,
significant electrolyte imbalance (low plasma-potassium
or plasma-magnesium concentrations), or significant
bradycardia. To minimise the risk of such adverse effects,
the following dose restrictions have been made and new
cautions and contra-indications added:
. Hydroxyzine is contra-indicated in patients with
prolonged QT-interval or who have risk factors for QTinterval prolongation;
. Avoid use in the elderly due to increased susceptibility
to the side-effects of hydroxyzine;
. Consider the risks of QT-interval prolongation and
torsade de pointes before prescribing to patients
taking drugs that lower heart rate or plasmapotassium concentration;
. In children with body-weight up to 40 kg, the
maximum daily dose is 2 mg/kg;
. In adults, the maximum daily dose is 100 mg;
. In the elderly, the maximum daily dose is 50 mg (if use
of hydroxyzine cannot be avoided);
. The lowest effective dose for the shortest period of
l CONTRA-INDICATIONS Acquired or congenital QT interval
prolongation . predisposition to QT interval prolongation
CONTRA-INDICATIONS, FURTHER INFORMATION
▶ QT interval prolongation Risk factors for QT interval
prolongation include significant electrolyte imbalance,
bradycardia, cardiovascular disease, and family history of
l CAUTIONS Bladder outflow obstruction . breathing
problems . cardiovascular disease . children . decreased
obstruction . stenosing peptic ulcer. susceptibility to
angle-closure glaucoma . urinary retention
▶ Children Children have an increased susceptibility to sideeffects, particularly CNS effects.
l INTERACTIONS → Appendix 1: antihistamines, sedating
▶ Rare or very rare Severe cutaneous adverse reactions
interval prolongation .respiratory disorders .respiratory
tract dryness . seizure (with high doses). sexual
SIDE-EFFECTS, FURTHER INFORMATION Paradoxical
stimulation may occur rarely, especially with high doses or
in the elderly. Drowsiness may diminish after a few days of
BNF 78 Allergic conditions 285
l ALLERGY AND CROSS-SENSITIVITY Manufacturer advises
hydroxyzine should be avoided in patients with previous
hypersensitivity to cetirizine or other piperazine
derivatives, and aminophylline.
l PREGNANCY Manufacturers advise avoid—toxicity in
animal studies with higher doses. Use in the latter part of
the third trimester may cause irritability, paradoxical
excitability, and tremor in the neonate.
l BREAST FEEDING Manufacturer advises avoid—expected
to be present in milk but effect unknown.
l HEPATIC IMPAIRMENT Manufacturer advises caution in
mild to moderate impairment (increased risk of
accumulation); avoid in severe impairment.
Dose adjustments Manufacturer advises dose reduction of
33% in mild to moderate impairment.
Dose adjustments Manufacturers advise reduce daily dose
by half in moderate to severe renal impairment.
l EFFECT ON LABORATORY TESTS May interfere with
methacholine test—manufacturer advises stop treatment
96 hours prior to test. May interfere with skin testing for
allergy—manufacturer advises stop treatment one week
Driving and skilled tasks Drowsiness may affect
performance of skilled tasks (e.g. cycling or driving);
sedating effects enhanced by alcohol.
l MEDICINAL FORMS There can be variation in the licensing of
different medicines containing the same drug. Forms available
from special-order manufacturers include: oral suspension, oral
CAUTIONARY AND ADVISORY LABELS 2
▶ Hydroxyzine hydrochloride (Non-proprietary)
Hydroxyzine hydrochloride 10 mg Hydroxyzine 10mg tablets | 84 tablet P £1.20–£1.65 DT = £1.65
Hydroxyzine hydrochloride 25 mg Hydroxyzine 25mg tablets | 28 tablet P £0.62–£0.85 DT = £0.85
▶ Atarax (Alliance Pharmaceuticals Ltd)
Hydroxyzine hydrochloride 10 mg Atarax 10mg tablets |
Hydroxyzine hydrochloride 25 mg Atarax 25mg tablets | 28 tablet P £0.62 DT = £0.85
▶ Child 3–17 years: 1 mg twice daily
▶ Adult: 1 mg twice daily, increased if necessary to 2 mg
twice daily, to be taken with food
Allergic rhinitis in readily sedated patients
▶ Adult: Initially 0.5–1 mg once daily, dose to be taken at
l CONTRA-INDICATIONS Avoid in Acute porphyrias p. 1058
l INTERACTIONS → Appendix 1: antihistamines, sedating
▶ Common or very common Anxiety . insomnia . irritability
▶ Uncommon Cystitis . dizziness . dry mouth . skin reactions
▶ Rare or very rare Hepatitis . sedation . seizure . StevensJohnson syndrome . weight increased
SIDE-EFFECTS, FURTHER INFORMATION Drowsiness is a
significant side-effect with most of the older
antihistamines although paradoxical stimulation may
occur rarely, especially with high doses or in children and
the elderly. Drowsiness may diminish after a few days of
treatment and is considerably less of a problem with the
l PREGNANCY Most manufacturers of antihistamines advise
avoiding their use during pregnancy; however, there is no
evidence of teratogenicity. Use in the latter part of the
third trimester may cause adverse effects in neonates such
as irritability, paradoxical excitability, and tremor.
l BREAST FEEDING Most antihistamines are present in
breast milk in varying amounts; although not known to be
harmful, most manufacturers advise avoiding their use in
mothers who are breast-feeding.
Driving and skilled tasks Drowsiness may affect
performance of skilled tasks (e.g. driving or cycling);
sedating effects enhanced by alcohol.
l MEDICINAL FORMS There can be variation in the licensing of
different medicines containing the same drug. Forms available
from special-order manufacturers include: oral solution
CAUTIONARY AND ADVISORY LABELS 2, 21
Ketotifen (as Ketotifen fumarate) 200 microgram per
1 ml Zaditen 1mg/5ml elixir sugar-free | 300 ml P £8.91 DT =
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