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).

• Paracetamol and ibuprofen are well tolerated when used for short periods [BNF 54, 2007]:
• Both paracetamol and ibuprofen are licensed for the relief of pain and fever from 3 months of age:
• Both drugs are recommended for the management of feverish illnesses in children younger than 5 years of age [NICE, 2007a].
• For use in pregnancy or when breastfeeding, see Treatment in pregnancy/breastfeeding
• Seek specialist advice before prescribing to neonates younger than 4 weeks of age given the high risk of complications in this age group.
• People with known hypersensitivity to aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs), people with renal complications, or people with a known risk of gastrointestinal bleeding, should avoid ibuprofen. Paracetamol is often a safer option in older people.
• Paracetamol and ibuprofen rarely cause adverse effects when used in the short term [BNF 54, 2007]:
• Paracetamol has no notable adverse effects when used at the correct dosage.
• Ibuprofen may occasionally cause gastrointestinal adverse effects, such as discomfort, nausea, and diarrhoea.

• Paracetamol is the analgesic and antipyretic of choice because it can be used at the usual dosage and at any stage of pregnancy and during breastfeeding.
• Ibuprofen may be considered for use in breastfeeding and pregnant women, but it should not used beyond 27 weeks of gestation because of the increased risk of constriction of the ductus arteriosus:
• Constriction is related to gestational age; it is rare before week 27, but its incidence increases with advancing gestational age to 50–70% at 32 weeks and up to 100% with exposure from week 34 onwards.
• The effect appears not to be dose dependent.
• If use of ibuprofen is unavoidable, fetal circulation should be monitored regularly (once or twice weekly) with Doppler sonography, and medication use should be stopped as soon as signs of ductal constriction appear.

[Schaefer et al, 2007]

• Recommend aciclovir 5% cream as a suitable topical antiviral for the treatment of cold sores.

• Two topical antiviral preparations are available on prescription and over the counter without prescription:
• Aciclovir 5% cream is available to buy in pharmacies, supermarkets, and other stores as it is classed under the General Sale List (GSL).
• Penciclovir 1% cream is only available through pharmacies.
• For further information on the use of topical antiviral preparations, see How to apply topical antiviral preps

• Aciclovir 5% cream is preferred over penciclovir 1% cream:
• It requires less frequent application (five times a day for 5 days) than penciclovir 1% cream (every 2 hours during waking hours for 4 days).
• it is licensed for use under 12 years of age.
• It is less expensive than penciclovir 1% cream.
• CKS found no good evidence to indicate that either aciclovir 5% cream or penciclovir 1% cream is superior to the other. Consequently, the choice of topical antiviral will be influenced by the ease of application, its licensed uses and cost.
• One Chinese double-blind RCT (n = 248) found no significant differences in terms of efficacy endpoint, clinical cure rate, and safety, between those treated with aciclovir 3% cream (unavailable in UK) and penciclovir 1% cream [Lin et al, 2002].
• Another published study (n = 40) found that penciclovir 1% cream reduced healing time and duration of pain more than aciclovir 5% cream [Femiano et al, 2001]. However the sample size was small (n = 10 in each of four treatment arms). No information was given as to whether the trial was double blinded or randomized.
• Topical antivirals not recommended:
• Topical idoxuridine: one double-blind RCT found idoxuridine (15%, in 80% dimethyl sulfoxide) to be effective in reducing the mean duration of pain and healing time by approximately 1–2 days compared to control [Spruance et al, 1990a]. However, treatment was associated with a higher level of skin irritations. The 15% solution is not available in the UK. Only the 5% solution (Herpid^®) is available commercially in the UK.

• Recommended regimen:
• Topical aciclovir 5% cream: apply five times a day at approximately 4-hourly intervals, omitting the night-time application, for 5 days.
• The manufacturer advise that, if healing is not complete then treatment may be continued for up to an additional 5 days [ABPI Medicines Compendium, 2007]. However, CKS could not find any evidence to support this use.
• Topical penciclovir 1% cream: apply to lesions every 2 hours during waking hours, for 4 days.
• Topical antivirals should be used at the first sign of an attack (at erythema or prodromal stage — before vesicles appear).
• For further information, see Topical antivirals for cold sores
• Application of topical antiviral preparations:
• Topical antivirals should be dabbed on rather than rubbed in to minimize mechanical trauma to the lesions.
• Hands should be washed after application.
• Topical antiviral preparations should not be shared with other people as this may spread infection.
• Topical antiviral preparations rarely cause adverse effects when used in the short term:
• The most common adverse effects are transient burning or stinging following application and allergic reactions to excipients (e.g. propylene glycol).

[Barbarash, 2001; BNF 54, 2007]