Pivmecillinam

How it works

After absorption it is hydrolysed to mecillinam, which binds penicillin-binding protein 2 and inhibits bacterial cell wall synthesis, with particular activity against Gram-negative organisms such as Escherichia coli.

Prescribing in practice

• It is contraindicated in patients with a history of penicillin hypersensitivity owing to the risk of cross-reactivity, including anaphylaxis.
• It should be taken with food and an adequate volume of fluid while sitting or standing upright to reduce the risk of oesophageal irritation.
• Pivmecillinam is associated with a risk of carnitine depletion and is not recommended where carnitine deficiency is a concern or for prolonged or repeated courses without specialist advice.

Monitoring

Routine laboratory monitoring is not generally required for short courses; review clinical response and reassess if symptoms fail to resolve.

Counselling the patient

• Take each dose with food and plenty of water, and do not lie down immediately afterwards.
• Complete the full course even if symptoms improve, and report any rash, swelling or difficulty breathing urgently.

Evidence & guidelines

It is recommended by NICE as a first-line option for uncomplicated urinary tract infection; consult current guidance for local antimicrobial recommendations.