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Inhaled Antibiotics — Bronchiectasis & Cystic Fibrosis Pregnancy: Use with caution — systemic aminoglycosides are ototoxic to foetus (VIII nerve damage); inhaled route has low systemic absorption; risk/benefit discussion with specialist CF centre required

Tobramycin Inhalation

Brand names: TOBI, TOBI Podhaler, Bramitob

Adult dose

Dose: 300 mg nebulised twice daily (TOBI); or 112 mg inhaled twice daily (TOBI Podhaler — 4 capsules)
Route: Nebulised or inhaled powder
Frequency: Twice daily in 28-day cycles (28 days on, 28 days off)
Max: 300 mg twice daily (nebulised)
Cyclic therapy: 28 days on, 28 days off. TOBI Podhaler preferred — faster administration (6 min vs 20 min). Rinse mouth after use. Monitor renal function and audiometry. Administer bronchodilator 15–30 min before nebulised dose.

Paediatric dose

Dose: 300 mg twice daily (nebulised) from age 6; TOBI Podhaler from age 6 mg/kg
Route: Nebulised or inhaled powder
Frequency: Twice daily in 28-day cycles
Max: 300 mg twice daily
Licensed from age 6 in CF with Pseudomonas aeruginosa; seek specialist paediatric CF/respiratory opinion

Dose adjustments

Renal

Monitor renal function — aminoglycoside; reduce dose or increase interval if eGFR falls; systemic absorption is low but can accumulate in renal impairment

Hepatic

No specific adjustment

Paediatric weight-based calculator

Licensed from age 6 in CF with Pseudomonas aeruginosa; seek specialist paediatric CF/respiratory opinion

Clinical pearls

  • Primary indication: suppression (not eradication) of chronic Pseudomonas aeruginosa colonisation in cystic fibrosis — inhaled tobramycin does not cure Pseudomonas but reduces bacterial load, exacerbation frequency, and lung function decline
  • Cyclic therapy (28 on/28 off): alternating cycles prevent resistance development and maintain drug efficacy; during off months, aztreonam lysine inhalation (Cayston) is sometimes alternated for continuous anti-pseudomonal cover
  • MHRA / NICE CF guidance: recommended for CF patients with confirmed P. aeruginosa colonisation; also used in non-CF bronchiectasis with P. aeruginosa colonisation (off-label but EMBARC consensus-supported)
  • TOBI Podhaler advantage: dry powder inhaler — no nebuliser required; much faster (6 vs 20 minutes); more convenient; particularly useful for young active CF patients
  • Audiometry monitoring: MHRA recommends annual audiometry for patients on repeated cycles of inhaled tobramycin; ototoxicity risk lower than IV but cumulative exposure over years in CF patients is significant
  • Resistance surveillance: send sputum for P. aeruginosa susceptibility testing at least annually; if tobramycin MIC rises (above 16 mg/L), consider switch to colistimethate or aztreonam

Contraindications

  • Known hypersensitivity to aminoglycosides
  • Myasthenia gravis (aminoglycoside neuromuscular blockade — rare with inhaled but caution)

Side effects

  • Voice alteration and pharyngitis (inhaled powder formulation)
  • Cough
  • Ototoxicity (tinnitus, hearing loss — rare with inhaled but monitor audiometry)
  • Bronchoconstriction (pre-treat with bronchodilator)
  • Tinnitus (early warning sign of ototoxicity)

Interactions

  • IV aminoglycosides (systemic aminoglycoside treatment — additive ototoxicity and nephrotoxicity; avoid concurrent IV tobramycin when on inhaled tobramycin)
  • Loop diuretics (furosemide — additive ototoxicity; MHRA warning)

Monitoring

  • Sputum culture and P. aeruginosa susceptibility testing (annually)
  • Audiometry (annually — ototoxicity surveillance)
  • Renal function and serum tobramycin levels (if systemic absorption suspected or concurrent IV aminoglycosides)
  • Spirometry (FEV1 — treatment response)
  • Tinnitus or hearing loss (instruct patient to report immediately)

Reference: BNFc; BNF 90; NICE CF Guideline NG78; MHRA SPC TOBI; Cystic Fibrosis Trust Antibiotic Guidelines; EMBARC Bronchiectasis Guidelines 2017. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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