pivmecillinam
Regulatory sources consulted
Approved indications
- Acute uncomplicated cystitis due to mecillinam-susceptible bacteria in adults.
Contraindications
Absolute
- Hypersensitivity to pivmecillinam, mecillinam, penicillins, cephalosporins, or excipients.
- A disorder that impairs esophageal transit.
- Carnitine transporter deficiency, methylmalonic aciduria, or propionic acidemia.
Clinical warnings
- Major warning · It may cause severe hypersensitivity or anaphylaxis. Review any history of immediate beta-lactam reactions before use and discontinue if an allergic reaction occurs. — CIMA/AEMPS, ficha técnica 81499
- Major warning · It may cause Clostridioides difficile-associated diarrhea during or after treatment; assess significant diarrhea and avoid antiperistaltic drugs if colitis is suspected. — CIMA/AEMPS, ficha técnica 81499
- Major warning · Swallow the tablet with at least half a glass of liquid to avoid esophageal lodging and ulceration. — CIMA/AEMPS, ficha técnica 81499
- Major warning · Avoid prolonged or repeated courses because of carnitine depletion; avoid in porphyria and discontinue for a severe skin reaction. — CIMA/AEMPS, ficha técnica 81499
- Major warning · Maternal exposure near delivery may cause a false-positive neonatal screen for isovaleric acidemia; inform the neonatal team. — CIMA/AEMPS, ficha técnica 81499
Drug interactions
- ModerateProbenecid
Mechanism: It reduces renal tubular secretion and may increase and prolong antibiotic exposure.
Recommendation: Avoid the combination unless deliberately indicated and monitor toxicity.
CIMA/AEMPS, ficha técnica 81499
- HighValproic acid, valproate, and other pivalic-acid-releasing drugs
Mechanism: They increase the risk of carnitine depletion.
Recommendation: Avoid the combination.
CIMA/AEMPS, ficha técnica 81499
- ModerateBacteriostatic antibiotics
Mechanism: They may antagonize the bactericidal action of mecillinam.
Recommendation: Avoid the combination when possible.
CIMA/AEMPS, ficha técnica 81499
Adverse events
Common (≥1%)
Nausea, diarrhea, and rash
Rare but serious
Anaphylaxis, C. difficile colitis, and severe cytopenias
Pregnancy and lactation
It may be used during pregnancy when clinically indicated and during breastfeeding. If used near delivery, report the possibility of a false-positive neonatal screen for isovaleric acidemia.
Recent literature (PubMed)
Urinary tract infections (UTIs) are associated with 25-40% of antibiotics consumed in primary care and are, therefore, driving antibiotic resistance. The worldwide increase in antibiotic resistance especially in Escherichia coli has complicated the treatment choices for UTIs and absence of effective oral antibiotics may lead to increasing need for more effective treatments. In this review we focus on the importance of the correct diagnosis of UTI as based on proof of urinary pathogens in the urine and discuss diagnostic measures including microscopy, dipstick, and culture. Antibiotic treatment can often await diagnostic measures with pain relief such as ibuprofen. The risk of an uncomplicated UTI leading to pyelonephritis is low (1-2%) and presence of bacteria in the bladder leaves some time for the immune system to react. Three antibiotics are recommended as based on their activity, and low propensity to select for resistance, i.e. nitrofurantoin, fosfomycin, and pivmecillinam, and in general, 3-5 days of treatment will suffice. Understanding the usual benign course of uUTIs can help reduce antibiotic treatment in many cases, e.g. starting treatment by pain relief and awaiting the course of infection without antibiotics. Better rapid tests in primary care are urgently needed to enforce such policies.
Most guidelines recommend nitrofurantoin, fosfomycin, and sometimes pivmecillinam for uncomplicated urinary tract infections (UTIs), but direct comparisons between these antibiotics are needed. This study evaluated the effectiveness and safety of a single dose of fosfomycin compared with two doses of fosfomycin and short-course regimens of nitrofurantoin and pivmecillinam in women with UTI symptoms. This phase 4, pragmatic, multicentre, parallel-group, open-label, randomised clinical trial was conducted in Spanish primary care centres from 2022 to 2024. Women aged 18 years or older with at least one UTI-specific symptom (dysuria, urinary urgency, urinary frequency, or suprapubic tenderness) and a positive urine dipstick test for either nitrites or leukocyte esterase were randomly assigned (1:1:1:1) to one of four treatments: a single 3 g dose of fosfomycin, two 3 g doses of fosfomycin, nitrofurantoin (100 mg three times per day for 5 days), or pivmecillinam (400 mg three times per day for 3 days). Doctors and patients were not masked to group assignment. The primary outcome was the proportion of patients with clinical resolution (defined as the disappearance of all infection symptoms) at day 7. This trial is registered with ClinicalTrials.gov (NCT04959331) and EudraCT (2021-001332-26) and is completed. Of the 804 patients assessed for eligibility between April 4, 2022 and Nov 14, 2024, 768 patients were randomly allocated (191 to the single-dose fosfomycin group, 194 to the two-dose fosfomycin group, 190 to the nitrofurantoin group, and 193 to the pivmecillinam group). Patients had a median age of 48 years (IQR 34-63). Race and ethnicity data were not collected. Among the 720 women with available data included in the primary analysis, single-dose fosfomycin had the lowest proportion of clinical resolution (109 [59%] of 185 patients), while nitrofurantoin had the highest (128 [74%] of 172 patients; difference 15·5 percentage points [95% CI 5·9 to 25·1] vs single-dose
Antibiotic resistance occurs when microorganisms resist the drugs used against the infection caused by them and neutralize their effects over time using various mechanisms. These mechanisms include preventing drug absorption, changing drug targets, drug inactivating, and using efflux pumps, which ultimately cause drug resistance, which is named pan-drug-resistant (PDR) infection if it is resistant to all antimicrobial agents. This type of drug resistance causes many problems in society and faces the health system with difficulties; therefore their treatment is crucial and encourages doctors to develop new drugs to treat them. PDR Gram-negative bacteria, including Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, and Escherichia coli are among the most significant resistant bacteria to many antimicrobial agents, and only a limited range of antibiotics, especially synergistically are effective on them. For the therapy of PDR A. baumannii, tigecycline in combination with colestimethate, imipenem, amikacin, and ampicillin-sulbactam are the most effective treatments. The utilization of β-lactamase inhibitors such as ceftolozane-tazobactam, ceftazidime-avibactam, or imipenem-cilastatin-relebactam has the most efficacy against PDR P. aeruginosa. The PDR K. pneumoniae has been treated in the last decades with tigecycline and colistin, but currently, nitrofurantoin, fosfomycin, and pivmecillinam seem to be the most effective agent for the therapy of PDR E. coli. While these drugs impressively struggle with PDR pathogens, due to the daily increase in antibiotic resistance in microorganisms worldwide, there is still an urgent need for the expansion of novel medicines and methods of combating resistance.
Pivmecillinam is the oral prodrug of mecillinam. Following absorption, the pivaloyl ester is hydrolyzed, releasing the active mecillinam into systemic circulation. It is a narrow spectrum amidino(penicillin) antibiotic with activity against the main uropathogens. Pivmecillinam has been used for decades in the Nordic countries as one of the main drugs for uncomplicated urinary tract infection (uUTI) with resistance levels in Escherichia coli remaining around 5%. A literature search was performed via PubMed during January-February 2026. The review centers on a brief mention of the mechanism of action, resistance mechanisms, pharmacokinetics, pharmacokinetic/pharmacodynamics, adverse effects, and clinical use. Pivmecillinam is stable against many broad-spectrum beta-lactamases increasing its versatility as an empiric antibiotic. The main indication is uUTI, but it is also used for treatment of acute pyelonephritis. The review addresses clinical experience, dose and duration of treatment with suggestions for dosing recommendations. There remains some debate on the ideal dose and duration of treatment. Pivmecillinam can also be used for treatment of some bacterial diarrhea types. Pivmecillinam can play an important role as empiric and directed treatment for UTIs due to its beneficial antibacterial spectrum against common uropathogens, stability toward beta-lactamases, minor effect on microbiomes and general safety.