Pivmecillinam hydrochloride

How it works

After absorption it is hydrolysed to mecillinam, which binds penicillin-binding protein 2 to disrupt cell-wall synthesis, giving activity predominantly against Gram-negative urinary pathogens such as Escherichia coli.

Prescribing in practice

• Although a penicillin, it should be avoided in patients with penicillin hypersensitivity, so allergy status must be checked before prescribing.
• It is intended for lower urinary tract infection and, like other oral pivalate prodrugs, is not suitable for prolonged or repeated courses owing to the risk of carnitine depletion.
• Take with adequate fluids while seated or standing to reduce the risk of oesophageal irritation, and avoid in conditions causing oesophageal obstruction or stasis.

Monitoring

No routine laboratory monitoring is required for short treatment courses; reassess if symptoms do not resolve or recur.

Counselling the patient

• Take the tablets with plenty of water and complete the full course.
• Tell us if you have ever had an allergic reaction to penicillin.
• Seek advice if your symptoms do not improve within a couple of days or if you develop a rash.

Evidence & guidelines

NICE guidance lists pivmecillinam as a first-line antibiotic option for uncomplicated lower urinary tract infection.