BP

Metronidazole

Proprietary

Flagyl^® (Winthrop Pharmaceuticals UK Ltd) (Aventis UK Ltd), Metrolyl^® (Sandoz Ltd), Flagyl^® injection (Winthrop Pharmaceuticals UK Ltd), metronidazole (non-proprietary, see BNF for details)

Group

Antimicrobial

Uses/indications

Treatment of anaerobic infection with a wide range of activity, prophylaxis in surgery (anaerobic bacteria and anaerobic streptococci), clostridium, Trichomonas vaginalis, Eubacterium, Gardnerella vaginalis, puerperal sepsis, bacterial vaginosis, gingivitis

Type of drug

POM

Presentation

Tablets, suspension, suppositories, pre-prepared IV injections and infusions

Dosage

Oral: stat 800 mg then 400–500 mg t.d.s.
IV: 500 mg t.d.s.
P.R.: 1 g t.d.s. for 3 days max, then 1 g b.d. treatment of bacterial vaginosis as for oral, or 2 g single dose

Route of admin

Oral, P.R., IV, IM

Contraindications

In pregnancy and breastfeeding avoid high dosage, avoid alcohol, known hypersensitivity to metronidazole

Side effects

Unpleasant taste in mouth, furry tongue, nausea, vomiting, rashes, headache, drowsiness, dizziness, dark urine and, very rarely, angio-oedema

Interactions

Alcohol – disulfiram-like reaction – avoid during treatment and for 48 h post course
Antacids – cimetidine inhibits the metabolism of metronidazole
Anticoagulants – enhances the effect of warfarin but no interaction with heparin
Antiepileptics – inhibits the metabolism of phenytoin; phenobarbital accelerates metabolism of metronidazole

Oestrogens – reduces the effect of the combined oral contraceptive pill

Pharmacodynamic properties

Antimicrobial effective against a wide range of infections with antiprotozoal and antibacterial actions

Fetal risk

Avoid high-dose regimens; use in first trimester can cause midline facial defects, cardiac defects, genital defects and limb defects, but has been used with little effect in last two trimesters

Breastfeeding

Significant amounts secreted; avoid large single doses

BP

Erythromycin stearate

Proprietary

Erythrocin^® (Amdipharm PLC)
Erythromycin (non-proprietary, see BNF for details)

Group

Antibiotic, macrolide

Uses/indications

Used in penicillin-sensitive clients, penicillin-resistant organisms, syphilis, chlamydia, gonorrhoea, respiratory infection, treatment of infection sensitive to erythromycin, prophylaxis in management of pre-term rupture of membranes

Type of drug

POM

Presentation

Tablets, capsules, powder for reconstitution, granules, suspension

Dosage

1–2 g/day in even doses, depending on the severity of infection
Oral: 250–500 mg q.d.s. or 0.5–1 g b.d.

Syphilis/chlamydia: 500 mg q.d.s. for 14 days; IV: 25–50 mg/kg daily or 1–2 g in 6 even doses

Route of admin

Oral, IV

Contraindications

Hypersensitivity, hepatic dysfunction

Side effects

Nausea, vomiting, diarrhoea, fever, skin eruptions, urticaria, rashes, cardiac arrhythmias; in large doses – reversible hearing loss, hepatic dysfunction, thrombophlebitis following IV administration, allergic response rare with mild anaphylaxis

Interactions

Anticoagulants – effect of warfarin enhanced
Antihistamines – inhibits the metabolism of terfenadine, causing dangerous cardiac arrhythmias
Cisapride – can cause cardiotoxicity and arrhythmias
Ergotamines – acute ergot toxicity, rapid peripheral vasospasm and dysaesthesia
Theophylline – inhibition of metabolism of theophylline

Pharmacodynamic properties

Antimicrobial that attaches to a subunit of susceptible organisms and suppresses protein synthesis, destroying cell wall stability and making them vulnerable to attack. Active against both Gram-positive and Gram-negative bacteria, mycoplasms, treponema, chlamydia and gonorrhoea

Fetal risk

Crosses the placental barrier but not in appreciable quantities; fetal concentrations have found to be low, with no reports of congenital defects located except in animal studies – cardiovascular malformations if used in early pregnancy. However, manufacturers advise that, if used to treat maternal syphilitic infection during pregnancy, the infant may be born with congenital syphilis and should receive penicillin treatment following birth

Breastfeeding

Secreted in only small amounts in breast milk – considered safe with no ill effects reported, although manufacturers advise avoidance

BP

Cefuroxime

Proprietary

Cefuroxime (Sandoz Ltd); Zinacef (GlaxoSmithKlein UK),
Cephradine (non-proprietary, see BNF for details)

Group

Antibiotic – cephalosporin

Uses/indications

Against both Gram-positive and Gram-negative bacteria, prophylaxis with LSCS, UTI, respiratory infections

Type of drug

POM

Presentation

Capsules, syrup, powder for reconstitution

Dosage

Oral: 250–500 mg b.d. or 0.5–1 g b.d.
IM, IV: 500 mg–1 g q.d.s. given over 3–5 min

Route of admin

Oral, IM, IV

Contraindications

Renal dysfunction, known hypersensitivity to cephalosporins, caution in penicillin hypersensitivity

Side effects

Nausea, diarrhoea and hypersensitivity – usually mild, headache, dizziness, dyspnoea

Interactions

Nil specific to cephradine:
Anticoagulants – effect of warfarin enhanced
Uricosurics – excretion is reduced by probenecid
Oestrogens – reduces the effect of the combined oral contraceptive pill

Pharmacodynamic properties

Broad-spectrum bactericidal drug active against Gram-positive organisms, e.g. staphylococci, streptococci, Streptococcus pyogenes, Streptococcus pneumoniae, and Gram-negative organisms such as Escherichia coli, Haemophilus influenzae, salmonella. Highly active against penicillinase-producing staphylococci. e.g. Saureus

Fetal risk

No reports of congenital defects located, although manufacturers advise safety not established

Breastfeeding

Considered safe, although manufacturers advise caution – as for amoxicillin