TOBI PODHALER
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TOBI PODHALER (TOBI PODHALER).
Tobramycin is an aminoglycoside antibiotic that binds to the 30S ribosomal subunit of susceptible bacteria, causing misreading of mRNA, inhibition of protein synthesis, and cell death. It is bactericidal against Pseudomonas aeruginosa.
| Metabolism | Tobramycin is not significantly metabolized; it is primarily excreted unchanged by the kidneys via glomerular filtration. |
| Excretion | Renal: approximately 90% of absorbed dose excreted unchanged in urine within 24 hours. Biliary/fecal: minimal (<5%). |
| Half-life | Terminal elimination half-life: approximately 3-4 hours in patients with cystic fibrosis. Clinically, following inhalation, systemic half-life does not directly guide dosing frequency due to local action in airways. |
| Protein binding | Tobramycin is 0-10% bound to plasma proteins. |
| Volume of Distribution | 0.26-0.42 L/kg in cystic fibrosis patients, indicating distribution primarily into extracellular fluid. |
| Bioavailability | Inhalation: absolute bioavailability is approximately 11.5% of the delivered dose (deposited in lungs); systemic absorption is minimal compared to intravenous tobramycin. |
| Onset of Action | Inhalation: clinical improvement (e.g., lung function) observed within 1-2 weeks of continuous therapy, but local antimicrobial effect begins immediately upon deposition. |
| Duration of Action | Inhalation: duration of antimicrobial effect at airway surface fluid is approximately 12 hours, supporting twice-daily dosing. Clinical trials show sustained improvement over 28-day cycles. |
| Molecular Weight | 467.52 |
Inhalation of 4 capsules (112 mg) twice daily using the Podhaler device, 12 hours apart, for 28 days on/28 days off cycles.
| Dosage form | POWDER |
| Renal impairment | No dose adjustment recommended for mild to moderate renal impairment. Insufficient data for severe renal impairment (CrCl < 30 mL/min); use with caution. |
| Liver impairment | No specific dose adjustment guidelines for hepatic impairment. Use with caution in severe hepatic impairment (Child-Pugh class C) due to limited data. |
| Pediatric use | Approved for children aged 6 years and older. Weight-based dosing not required; same as adult dose: 4 capsules (112 mg) inhaled twice daily. |
| Geriatric use | No specific dose adjustment; use same as adult dose. Monitor for adverse effects due to potential age-related decline in renal function and comorbidities. |
| 1st trimester | Insufficient human data; animal studies show no teratogenicity at clinically relevant doses. Use only if potential benefit justifies risk. |
| 2nd trimester | No known fetal risk; consider maternal benefit versus potential risk. |
| 3rd trimester | No known fetal risk; consider maternal benefit versus potential risk. |
Clinical note
Comprehensive clinical and safety monograph for TOBI PODHALER (TOBI PODHALER).
| Placental transfer | Placental transfer of tobramycin occurs; however, inhaled administration results in low systemic concentrations. The degree is minimal compared to IV dosing. |
| Breastfeeding | Inhaled tobramycin has negligible systemic absorption; minimal excretion into breast milk is expected. Compatible with breastfeeding. |
■ FDA Black Box Warning
Warning: Risk of nephrotoxicity and ototoxicity, especially in patients with renal impairment or those receiving other nephrotoxic/ototoxic drugs. Also, neuromuscular blockade risk, particularly with anesthetics or neuromuscular blocking agents.
| Serious Effects |
Hypersensitivity to tobramycin or any aminoglycosideKnown or suspected neuromuscular disorders (e.g., myasthenia gravis, botulism) due to potential for neuromuscular blockade
| Precautions | Nephrotoxicity: Monitor renal function; risk increased with high doses, prolonged therapy, or concomitant nephrotoxic drugs., Ototoxicity: Can cause irreversible bilateral vestibular and cochlear damage; monitor for dizziness, tinnitus, hearing loss., Neuromuscular blockade: May exacerbate muscle weakness; avoid in myasthenia gravis or other neuromuscular disorders., Bronchospasm: Can occur with inhalation; use with caution in patients with reactive airway disease., Superinfection: Prolonged use may result in overgrowth of nonsusceptible organisms. |
| Food/Dietary | No specific food interactions. Avoid alcohol as it may worsen dizziness or ototoxicity. Maintain adequate hydration. |
Loading safety data…
| Lactation Rating |
| L1 |
| Teratogenic Risk | FDA Pregnancy Category C. Animal studies at 2 times the maximum recommended human dose showed embryofetal toxicity including reduced fetal weights and increased resorptions. No adequate human studies. Risk cannot be ruled out. Use only if potential benefit justifies potential risk. First trimester: defer if possible. Second/third trimesters: consider risk/benefit. |
| Fetal Monitoring | Monitor maternal pulmonary function (FEV1, oxygen saturation), signs of bronchospasm. Fetal monitoring: standard prenatal care including ultrasound for growth if indicated. No specific additional fetal monitoring required. |
| Fertility Effects | In animal studies, no effects on fertility at doses up to 2 times MRHD. Human data not available. No expected adverse effects on male or female fertility based on mechanism (inhaled tobramycin). |
| Clinical Pearls | TOBI PODHALER (tobramycin inhalation powder) is indicated for cystic fibrosis patients with Pseudomonas aeruginosa. Monitor for nephrotoxicity and ototoxicity; obtain baseline and periodic audiometry and renal function tests. Patients with known or suspected auditory or renal dysfunction require close monitoring. Bronchospasm can occur; administer a bronchodilator prior to use if bronchospasm develops. Do not reconstitute or use a nebulizer; it is a dry powder inhaler. |
| Patient Advice | Use only with the PODHALER device; do not swallow capsules. · Do not use if capsule is damaged or crushed. · Take as prescribed, typically twice daily for 28 days on/off cycle. · Do not skip doses; if a dose is missed, take as soon as remembered but not within 6 hours of the next dose. · Rinse mouth with water after each use to reduce risk of oral candidiasis. · Store capsules at room temperature away from moisture; do not refrigerate. · Report hearing loss, ringing in ears, dizziness, or changes in urination to healthcare provider. · Avoid pregnancy; use effective contraception during treatment. · Inform healthcare provider of all medications, especially other aminoglycosides, diuretics, or nephrotoxic drugs. |