Pivmecillinam

Oral
Acute uncomplicated cystitis

Oral
Chronic or recurrent bacteriuria

Hypersensitivity, porphyria.

Very high doses in poor renal function (risk of neurotoxicity) or heart failure. Avoid contact, skin sensitization may occur. Monitor serum K concentration, renal and haematological status. Spirochete infections particularly syphilis; suprainfection with penicillin-resistant organisms with prolonged use; avoid intrathecal route. May cause oesophageal injury.

Hypersensitivity reactions including uticaria; fever; joint pains; rashes; angioedema; serum sickness-like reactions; haemolytic anaemia; interstitial nephritis; neutropaenia; thrombocytopaenia; CNS toxicity including convulsions; diarrhoea; antibiotic-associated colitis. Induction of carnitine deficiency.
Potentially Fatal: Anaphylaxis.

Probenecid prolongs T1/2 of pivmecillinam. May cause prolonged bleeding when taken with anticoagulants. May decrease the efficacy of oral contraceptives. Increased risk of carnitine deficiency when used with valproate.

May interfere with diagnostic tests for urinary glucose using copper sulfate, direct Coomb's test, and test for urinary or serum proteins. May interfere with diagnostic tests that use bacteria.

Description: Pivmecillinam has the antimicrobial activity of mecillinam to which it is hydrolysed in vivo. It interferes with the synthesis of bacterial cell wall. It is active against many gm-ve bacteria, esp Enterobacteriaceae including Escherichia coli, Enterobacter, Klebsiella, Salmonella and Shigella spp; indole-positive Proteus and Serratia marcescens are resistant. It is inactivated by β-lactamases, but is more stable than ampicillin.
Pharmacokinetics:
Absorption: Well absorbed.
Distribution: Peak plasma concentrations about 1-2 hr after a 400 mg dose.
Metabolism: Hydrolysed to mecillinam, pivalic acid and formaldehyde.
Excretion: About 45% excreted in the urine as mecillinam within the first 6 hr.

Penicillins