What does Start Smart then Focus mean for prescribers?
Start Smart then Focus is the UK antimicrobial stewardship approach: start promptly with a justified choice, then review and refine.
- Start smart: document the indication and the allergy status, take cultures where this does not delay treatment, and follow local guidelines or the BNF first-line table.
- Give IV antibiotics immediately in suspected sepsis with high-risk features. Do not delay them for investigations.
- Prescribe a stop or review date. An open-ended course is a prescribing error.
- Focus: review at 48 to 72 hours with the clinical picture and microbiology. The options are stop, switch IV to oral, change to a narrower agent, or continue with a documented duration.
- Oral is the default when the patient can swallow and absorb and is not severely unwell. IV to oral switch is a recurring exam theme.
How do I handle a reported penicillin allergy?
Ask what happened, when, and what treatment was needed, because many penicillin allergy labels are wrong.
| History | Likely meaning | Prescribing consequence |
|---|---|---|
| Urticaria, angioedema, wheeze or collapse soon after a dose | True immediate allergy | Avoid penicillins; take cross-reactivity advice from the BNF |
| Severe delayed reaction such as blistering or organ involvement | True severe allergy | Avoid penicillins; seek specialist advice |
| Nausea, vomiting or diarrhoea | Intolerance or side effect | Not an allergy; record it as such |
| Unclear or remote history | Uncertain | Follow local penicillin allergy pathway |
Cross-reactivity with cephalosporins and carbapenems is mainly a concern after immediate or severe reactions. The BNF sets out the advice. For penicillin-allergic patients, the BNF and local guidance list alternatives for each infection.
What are common first-line antibiotics?
Use these as orientation only and always check the BNF and local guidance, which vary by area and resistance patterns.
| Infection | Usual first-line option | Exam point |
|---|---|---|
| Sore throat needing antibiotics | Phenoxymethylpenicillin | Check penicillin allergy |
| Low-severity community-acquired pneumonia | Amoxicillin | Severity assessment decides route and combinations |
| Uncomplicated lower UTI in non-pregnant women | Nitrofurantoin, or trimethoprim where resistance risk is low | Check eGFR and pregnancy |
| Non-severe cellulitis | Flucloxacillin | Check allergy; MRSA risk changes the choice |
Which antibiotic interactions and hazards does the exam favour?
| Antibiotic | Key hazard or interaction | Consequence |
|---|---|---|
| Clarithromycin, erythromycin | Simvastatin, atorvastatin | Raised statin levels, myopathy; simvastatin: do not combine, atorvastatin: suspend or limit the dose (BNF) |
| Clarithromycin | Warfarin | Raised INR; monitor closely |
| Macrolides, quinolones | Other QT-prolonging drugs | QT prolongation, arrhythmia |
| Rifampicin | Warfarin, DOACs, hormonal contraceptives, ciclosporin | Enzyme induction lowers their effect |
| Trimethoprim | Methotrexate | Additive folate antagonism, bone marrow suppression |
| Trimethoprim | ACE inhibitors, spironolactone | Hyperkalaemia |
| Ciprofloxacin | Tizanidine | Raised tizanidine levels; avoid |
| Quinolones | Theophylline, NSAIDs, corticosteroids | Seizures; tendon damage with corticosteroids |
| Metronidazole | Alcohol, warfarin | Avoid alcohol; raised INR |
| Flucloxacillin | Prolonged use | Cholestatic jaundice, which can appear after stopping |
Quinolone use is restricted by the MHRA to when other antibiotics are unsuitable because of disabling and potentially long-lasting side effects, including tendon rupture.
How are gentamicin and vancomycin monitored, and how is MRSA treated?
Gentamicin and vancomycin are nephrotoxic, so they need renal function and drug-level monitoring.
- Gentamicin: dose by weight according to local protocol, check creatinine, and take levels as the protocol states. It is ototoxic and nephrotoxic; take care with other nephrotoxic drugs and loop diuretics.
- Vancomycin: take trough levels before a dose, monitor renal function, and infuse IV slowly because rapid infusion causes infusion reactions. Oral vancomycin is not absorbed and is used for C. difficile.
- MRSA is resistant to flucloxacillin and most other beta-lactams. Follow local microbiology advice, which commonly uses vancomycin or teicoplanin IV for serious infection, with level monitoring.
Which antibiotics carry the highest C. difficile risk?
Broad-spectrum antibiotics carry the greatest risk of C. difficile infection, including cephalosporins, clindamycin, quinolones and co-amoxiclav.
- Older age, hospital stay and acid suppression with PPIs add to the risk.
- If suspected, send a stool sample and stop any antibiotic that is not essential.
- Avoid antimotility drugs such as loperamide.
- NICE guidance lists oral vancomycin or fidaxomicin as first-line treatment; metronidazole is no longer first choice. Check the BNF.
How do renal impairment, pregnancy and age change antibiotic choice?
Renal impairment changes the dose or the choice of renally cleared antibiotics, so check the BNF renal impairment section.
- Renal: aminoglycosides, vancomycin and trimethoprim need caution or adjustment. Nitrofurantoin is less effective and more toxic when renal function is low. Trimethoprim can raise creatinine without a true fall in GFR.
- Pregnancy: penicillins, cephalosporins and erythromycin are generally considered acceptable. Avoid tetracyclines, and avoid quinolones and aminoglycosides unless essential. Trimethoprim is a folate antagonist and needs caution in the first trimester; nitrofurantoin is avoided near term.
- Children: dose by weight or age band in the BNF for Children. Tetracyclines are avoided in younger children, and quinolones are used only when clearly justified.
Check yourself
- What are the four review options at 48 to 72 hours?
- What history separates penicillin allergy from intolerance?
- Which macrolide interaction with a statin is most important?
- Why does rifampicin make hormonal contraception unreliable?
- What must be monitored when giving gentamicin?
- Which antibiotic classes carry the most C. difficile risk?
- Which antibiotic should be avoided with methotrexate?
- Which antibiotics are avoided in pregnancy?
Questions people ask
What is Start Smart then Focus?
It is the UK stewardship approach: start antibiotics promptly with a documented indication and justified choice, then review at 48 to 72 hours and stop, switch to oral, change or continue.
Is every penicillin allergy label a true allergy?
No. Nausea or diarrhoea is intolerance. Immediate reactions such as urticaria, angioedema or anaphylaxis, and severe delayed reactions, count as true allergy and should be avoided.
Why do clarithromycin and statins matter?
Clarithromycin raises levels of some statins, especially simvastatin, increasing the risk of myopathy. Simvastatin should not be combined with it, so suspend the statin or choose another antibiotic; for atorvastatin, suspend it or limit the dose as the BNF advises.
Which antibiotics most often cause C. difficile infection?
Broad-spectrum agents such as cephalosporins, clindamycin, quinolones and co-amoxiclav carry the most risk, particularly in older hospital patients.
Related revision notes
Sources: BNF; BNF for Children; NICE guidance on antimicrobial prescribing; MHRA Drug Safety Update on fluoroquinolones; Start Smart then Focus antimicrobial stewardship toolkit. These notes are for exam revision and are not patient-specific advice; in the exam and in practice, the BNF is the authority.
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