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).

• Trimethoprim is available as a sugar-free suspension (50 mg/5 mL) or tablets (100 and 200 mg), and is licensed for children 6 weeks of age or older.
• Trimethoprim is suitable for most children:
• Trimethoprim may accumulate in the body of children with renal impairment. Use a different antibiotic or seek specialist advice about reducing the dose.
• Trimethoprim has the potential to interact with several drugs, including amiodarone, phenytoin, and ciclosporin. If the child is receiving one of these drugs for a chronic condition, it is advisable to use an alternative antibiotic.

[BNF 54, 2007]

• Advise parents that trimethoprim may cause gastrointestinal disturbances (e.g. nausea and vomiting, diarrhoea) and skin rashes, but these are quickly reversible on stopping treatment.

[BNF 54, 2007]

• Nitrofurantoin is available as a sugar-free oral suspension (25 mg/5 mL) and tablets (50 mg), and is licensed in children aged over 3 months. A modified-release capsule (100 mg) is also available but is not licensed for children under 12 years of age. Nitrofurantoin products are licensed specifically for use as a 7–day course.
• Nitrofurantoin should not be used in children:
• Who are known to be at risk of peripheral neuropathy, for example children with renal impairment, anaemia, diabetes mellitus, electrolyte imbalance, or vitamin B deficiency (nitrofurantoin can cause peripheral neuropathy, so susceptible children are at further increased risk).
• With renal insufficiency, as it may form inadequate concentrations in urine (and precipitate peripheral neuropathy).
• With glucose-6-phosphate dehydrogenase deficiency (as it may cause haemolysis).
• Serious adverse effects with nitrofurantoin are very rare when short courses are used. Nitrofurantoin does not interact with any drugs a child is likely to be taking.

[BNF 54, 2007]

• Advise parents:
• That it is common for nitrofurantoin to turn urine more yellow or brown than usual, and this is not a cause for concern.
• Nitrofurantoin frequently causes nausea, vomiting, and loss of appetite. Taking the drug with food enhances absorption, and improves gastrointestinal tolerance.

[Micromedex, 2006; BNF 54, 2007]

• Cefalexin is available as an sugar-free oral suspension (125 or 250 mg/5 mL), capsules, or tablets (both 250 or 500 mg), and is licensed from the age of 1 month onwards.
• Cefalexin can be used safely in most children:
• If the child has had a documented allergic reaction to penicillin, consider using another antibiotic belonging to a different class, as about 8% of penicillin-allergic people exhibit cross-reactivity to cephalosporins [DTB, 1996]. However, gastrointestinal adverse effects alone (e.g. nausea, vomiting, or diarrhoea) do not constitute an allergy to penicillin.
• There are no known clinically significant drug interactions with cefalexin.

[ABPI Medicines Compendium, 2005; BNF 54, 2007].

• Advise parents:
• That severe adverse effects with cefalexin are rare. Gastrointestinal symptoms are most common, particularly diarrhoea.
• To stop the drug and seek medical attention immediately if the child develops severe diarrhoea with bloody stools and is systemically unwell. This may be indicative of pseudomembranous colitis (a rare but serious reaction to cefalexin).
• Some children are allergic to cephalosporin antibiotics (including cefalexin), although this is very rare. Parents should seek urgent medical advice if their child develops a rash; swelling of the face, hands, or feet; or shortness of breath.

[ABPI Medicines Compendium, 2005]

• Amoxicillin and co-amoxiclav are available as a variety of powders, oral suspensions, capsules, or tablets and are suitable for children 1 month of age or older.
• Amoxicillin should only be used if the pathogen is known to be sensitive to it, as there is a high rate of resistance to it in the community.
• Some experts recommend that a double-dose should be used, and this is recommended for the treatment of 'severe' infections by the British National Formulary [BNF for Children, 2007] (pyelonephritis may be considered to be a severe infection). However, this practice varies; if in doubt seek expert advice.
• Amoxicillin and co-amoxiclav should not be taken by children who have true penicillin allergy. However, gastrointestinal adverse effects alone (e.g. nausea, vomiting, or diarrhoea) do not constitute an allergy to penicillin.
• Consider using an alternative antibiotic to co-amoxiclav if the child has a history of hepatic impairment. The Commission on Human Medicines (formerly the Committee on the Safety of Medicines) has advised that cholestatic jaundice may rarely occur during or shortly after the use of co-amoxiclav [CSM, 1997]. However, this is more common in men, in people over the age of 65 years, and with longer courses of treatment (over 14 days), and so is unlikely to be problematic in children receiving co-amoxiclav for short periods.

[BNF 54, 2007]

• Advise parents:
• That amoxicillin and co-amoxiclav are usually well tolerated, but nausea, vomiting, or diarrhoea can sometimes occur. These tend to be worse with co-amoxiclav, but taking the drug with meals may help to reduce these effects.
• Some children are allergic to penicillin antibiotics (including amoxicillin and co-amoxiclav), although this is very rare. Parents should seek urgent medical advice if their child develops a rash; swelling of the face, hands, or feet; or shortness of breath.

[ABPI Medicines Compendium, 2006; BNF 54, 2007]

• Paracetamol can be used safely in most children from 3 months of age [BNF 54, 2007].

• Advise parents that paracetamol is a safe drug when used at the correct dosage and that adverse effects are very rare [BNF 54, 2007].