Important aspects of prescribing information relevant to primary healthcare are covered in this section specifically for the drugs recommended in this CKS topic. For further information on contraindications, cautions, drug interactions, and adverse effects, see the electronic Medicines Compendium (eMC) (http://emc.medicines.org.uk), or the British National Formulary (BNF) (www.bnf.org).

• Permethrin is normally well tolerated, but burning, stinging, pruritus, and erythema may occur in a few people [ABPI Medicines Compendium, 2006].
• Alcohol-based solutions are more irritant than aqueous preparations. Rarely, skin irritation has been reported with aqueous malathion preparations.

• Mildly and moderately potent topical corticosteroids used for short periods are rarely associated with adverse effects.
• Skin atrophy is much more likely with potent and very potent topical corticosteroids.
• There is little risk of skin thinning with mild-to-moderately potent topical corticosteroids when used for up to 4 weeks [DTB, 2003].

• Sedating antihistamines cause sedation in 10–50% of people, which can persist into the next day [DTB, 2002a].
• Most non-sedating antihistamines have the potential to cause sedation, especially at higher doses. Advise people taking non-sedating antihistamines that they may cause sedation, and that the sedative effects are enhanced when combined with alcohol.

• Where possible, oral antihistamines should be avoided during pregnancy, especially during the first trimester.
• If an oral antihistamine is required to control pruritus during pregnancy, chlorphenamine is the antihistamine of choice [NTIS, 2002].