Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.
Choose, dose, review and narrow antibacterial treatment from syndrome severity, likely pathogens, resistance risk, source penetration and patient-specific toxicity rather than habit or drug familiarity.
Antibiotic choice begins with syndrome and severity. Community exposure, hospital contact, prior resistant isolates and anatomical source determine the initial spectrum. The same drug may be appropriate for uncomplicated infection and inadequate for meningitis, endocarditis, abscess or prosthetic infection because dose, penetration, bactericidal requirement and duration differ.
Targeted treatment uses organism identity, susceptibility, source and patient response. A laboratory 'sensitive' result does not guarantee clinical suitability when the drug cannot reach the compartment, is unsafe for the patient or has no evidence for the syndrome. Conversely, broad treatment should not continue merely because the patient improved before cultures returned.
Prescribing safety is dynamic. Acute kidney injury, obesity, critical illness, dialysis, drug interactions and absorption alter exposure. Therapeutic drug monitoring is part of treatment for selected aminoglycosides and glycopeptides. Every prescription needs a documented indication, dose, route, review date, duration and contingency if results or physiology change.
Shock, meningitis, neutropenic sepsis or rapidly progressive invasive infection requires prompt syndrome-specific empirical intravenous therapy after feasible cultures.
Recent broad antibiotics, hospitalisation, overseas healthcare, prior resistant isolate, indwelling devices and structural disease increase the chance standard first-line therapy will fail.
Persistent bacteraemia, collection, obstruction, necrotic tissue or prosthetic infection indicates a mechanical focus and should not trigger serial antibiotic substitutions alone.
New kidney injury, cytopenia, liver-test abnormality, rash, diarrhoea, QT prolongation or neurotoxicity may represent antimicrobial harm requiring urgent review.
Avoid after serious immediate beta-lactam hypersensitivity and reduce maintenance in renal impairment. Review sodium and potassium, liver tests and blood counts during longer exposure; piperacillin can delay methotrexate elimination, so check the full interaction plan and de-escalate promptly.
Use actual or adjusted weight and current renal function, avoid unmonitored accumulation and minimise other nephrotoxic or ototoxic drugs. Measure correctly timed concentrations and assess hearing and vestibular symptoms; pregnancy, myasthenia gravis or neuromuscular blockade requires specialist risk assessment.
Individualise the loading and maintenance plan to weight, renal function, dialysis and locally adopted concentration or exposure targets. Infuse slowly to reduce infusion reaction and reassess renal and hearing toxicity, especially with aminoglycosides, piperacillin-tazobactam or other nephrotoxins.
A full loading exposure may be needed in severe infection even with renal impairment, while later interval and maintenance must reflect clearance and measured levels.
Laboratory activity must be combined with site penetration, dose, infection burden, source control and clinical response before a targeted regimen is accepted.
Persistent fever from an abscess, thrombosis, drug reaction or malignancy will not improve simply because another antibiotic is added.
For many deep infections, the meaningful treatment clock depends on adequate drainage, debridement or bloodstream clearance rather than the first empirical dose.
Using the same empirical regimen for every source of severe infection.
Reducing all doses for renal impairment without considering the need for a loading dose.
Reading a susceptibility report without checking specimen quality and anatomical site.
Adding agents for persistent CRP while ignoring source control and clinical trajectory.
Allowing an empirical prescription to continue without an indication, review date and end plan.
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A stable patient started on broad intravenous therapy has blood cultures showing a susceptible streptococcus, rapid improvement and no undrained focus. What is the best stewardship action?
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.
Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes