Formulary
Hydroxyzine hydrochloride: Indications, Dosing, Side Effects and Interactions
Hydroxyzine is a sedating antihistamine which exerts its actions by antagonising the effects of histamine.
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Hydroxyzine hydrochloride: Indications, Dosing, Side Effects and Interactions
Hydroxyzine is a sedating antihistamine which exerts its actions by antagonising the effects of histamine.
Drug action
Hydroxyzine is a sedating antihistamine which exerts its actions by antagonising the effects of histamine.
Indications and dose
**Pruritus**
- **Child** (By Mouth): 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 according to weight.
- **Adult** (By Mouth): Initially 25 mg daily, dose to be taken at night; increased if necessary to 25 mg 3-4 times a day.
- **Elderly** (By Mouth): Initially 25 mg daily, dose to be taken at night; increased if necessary to 25 mg twice daily.
**Pruritus for hydroxyzine hydrochloride**
- **Child 6 months-5 years** (By mouth): 5-15 mg daily in divided doses, dose adjusted according to weight; maximum 2 mg/kg per day.
- **Child 6-17 years (body-weight up to 40 kg)** (By mouth): Initially 15-25 mg daily in divided doses, dose increased as necessary, adjusted according to weight; maximum 2 mg/kg per day.
- **Child 6-17 years (body-weight 40 kg and above)** (By mouth): Initially 15-25 mg daily in divided doses, increased if necessary to 50-100 mg daily in divided doses, dose adjusted according to weight.
Cautions
Bladder outflow obstruction; breathing problems; cardiovascular disease; children (in children); decreased gastrointestinal motility; dementia; elderly (in adults); epilepsy; hypertension; hyperthyroidism; myasthenia gravis; prostatic hypertrophy (in adults); pyloroduodenal obstruction; stenosing peptic ulcer; susceptibility to angle-closure glaucoma; urinary retention Cautions, further information Elderly In adults: Elderly patients are particularly susceptible to side-effects; manufacturers advise avoid or reduce dose. Children In children: Children have an increased susceptibility to side-effects, particularly CNS effects.
Contraindications
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 sudden cardiac death.
Side effects
Rare or very rare Severe cutaneous adverse reactions (SCARs); skin reactions Frequency not known Agranulocytosis; alopecia; anticholinergic syndrome; anxiety; appetite decreased; arrhythmias; asthenia; blood disorder; bronchial secretion viscosity increased; chest tightness; chills; coma; concentration impaired; confusion; constipation; depression; diarrhoea; dizziness; drowsiness; dry mouth; dry throat; dyskinesia (on discontinuation); epigastric pain; fever; flushing; gastrointestinal disorders; haemolytic anaemia; hallucination; headache; hepatic function abnormal; hyperhidrosis; hypotension; irritability; labyrinthitis; leucopenia; malaise; menstruation irregular; movement disorders; myalgia; nasal congestion; nausea; palpitations; paraesthesia; QT interval prolongation; respiratory disorders; respiratory tract dryness; seizure (with high doses); sexual dysfunction; sleep disorders; speech slurred; taste bitter; thrombocytopenia; tinnitus; tremor (with high doses); urinary disorders; vertigo; vision disorders; vomiting 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 treatment.
Interactions
**Other interactions (4):**
- Hydroxyzine is metabolized by alcohol dehydrogenase and CYP3A4/5 and an increase in hydroxyzine blood concentrations may be expected when hydroxyzine is coadministered with drugs known to be potent...
- Hydroxyzine Tablets may also have the following interactions: Methocholine test Treatment should be stopped for 96 hours prior to a methocholine test, to avoid effects on the test results (see...
- Cetirizine does not interact with other drug substances via cytochrome P450 Drugs which have effects on the brain Drugs which have effects on the brain will interact with antihistamines Drugs that...
- Decreased metabolism may result in accumulation of potentially toxic concentrations of unchanged antihistamine Ototoxic drugs It has been suggested that some sedating antihistamines could mask the...
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.
Breast feeding
Manufacturer advises avoid-expected to be present in milk but effect unknown.
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.
Renal impairment
Use with caution. M Dose adjustments Reduce daily dose by half in moderate to severe renal impairment. M
Medicinal forms
Solution,Tablet,Solution
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
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