Drug reference
Allergic rhinitis ▶BY MOUTH ▶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 ▶BY MOUTH ▶Adult: Initially 0.5–1 mg once daily, dose to be taken at night
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Avoid in Acute porphyrias p. 1120
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Epilepsy. prostatic hypertrophy (in adults). pyloroduodenal obstruction. susceptibility to angle- closure glaucoma. urinary retention
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→Appendix 1: antihistamines, sedating
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▶Common or very common Anxiety. insomnia. irritability ▶Uncommon Cystitis. dizziness. dry mouth. skin reactions ▶Rare or very rare Hepatitis. sedation. seizure. Stevens- Johnson 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 newer antihistamines.
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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.
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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.
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There can be variation in the licensing of different medicines containing the same drug. Forms available from special-order manufacturers include: oral solution Oral solution CAUTIONARY AND ADVISORY LABELS 2, 21 ▶Zaditen (CD Pharma Srl) Ketotifen (as Ketotifen fumarate) 200 microgram per 1 ml Zaditen 1mg/5ml elixir sugar-free | 300 ml P £8.91 DT = £8.91 Tablet CAUTIONARY AND ADVISORY LABELS 2, 21 ▶Zaditen (CD Pharma Srl) Ketotifen (as Ketotifen fumarate) 1 mg Zaditen 1mg tablets | 60 tablet P £7.53 DT = £7.53
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Driving and skilled tasks Drowsiness may affect performance of skilled tasks (e.g. driving or cycling); sedating effects enhanced by alcohol.
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1 mg twice daily, increased if necessary to 2 mg
First-line fragment. Read the complete Indications and Dose section above.
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Initially 0.5–1 mg once daily, dose to be taken at
First-line fragment. Read the complete Indications and Dose section above.
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