General guidance
- All antihistamines are of potential value in the treatment of nasal allergies, particularly seasonal allergic rhinitis (hay fever), and may be of some value in vasomotor rhinitis. They reduce rhinorrhoea and sneezing but are usually less effective for nasal congestion.
- Oral antihistamines are also of some value in preventing urticaria and are used to treat urticarial rashes, pruritus and insect bites and stings; they are also used in drug allergies.
- Antihistamines differ in their duration of action and the degree of sedation they cause.
- The sedating activity is sometimes used to alleviate the pruritus associated with some allergies. There is little evidence that any one of the sedating antihistamines is superior to another and patients appear to vary widely in their responses.
- For maximum benefit, especially in seasonal allergic rhinitis (hay fever) treatment should be started 2-3 weeks before symptoms appear.
Recommended drugs
Non sedating
Loratadine £
Cetirizine £
Fexofenadine ££
Mizolastine ££
Sedating
Chlorphenamine £
Hydroxyzine £
Drug Traffic Light Key:
Green – On Formulary
Amber – Restricted use, see local guidelines
Purple – Specialist use/initiation
Red – Non Formulary
Relative Costs Key (where indicated):
£££££ - high
£££ - moderate
£ - low