INTERACTIONS Concurrent and/or sequential use of tobramycin inhalation solution with other drugs with neurotoxic, nephrotoxic, or ototoxic potential should be avoided ( 7.1 ). Concomitant administration with ethacrynic acid, furosemide, urea, or intravenous mannitol is not recommended due to possible enhancement of aminoglycoside toxicity ( 7.2 ).
7.1 Drugs with Neurotoxic, Nephrotoxic or Ototoxic Potential Concurrent and/or sequential use of tobramycin inhalation solution with other drugs with neurotoxic, nephrotoxic, or ototoxic potential should be avoided.
7.2 Diuretics Some diuretics can enhance aminoglycoside toxicity by altering aminoglycoside concentrations in serum and tissue. Tobramycin inhalation solution should not be administered concomitantly with ethacrynic acid, furosemide, urea, or intravenous mannitol. The interaction between inhaled mannitol and tobramycin inhalation solution has not been evaluated.
7.1 Drugs with Neurotoxic, Nephrotoxic or Ototoxic Potential Concurrent and/or sequential use of tobramycin inhalation solution with other drugs with neurotoxic, nephrotoxic, or ototoxic potential should be avoided.
7.2 Diuretics Some diuretics can enhance aminoglycoside toxicity by altering aminoglycoside concentrations in serum and tissue. Tobramycin inhalation solution should not be administered concomitantly with ethacrynic acid, furosemide, urea, or intravenous mannitol. The interaction between inhaled mannitol and tobramycin inhalation solution has not been evaluated.
CONTRAINDICATIONS: A hypersensitivity to any aminoglycoside is a contraindication to the use of tobramycin. A history of hypersensitivity or serious toxic reactions to aminoglycosides may also contraindicate the use of any other aminoglycoside because of the known cross-sensitivity of patients to drugs in this class.
AND PRECAUTIONS Bronchospasm: Can occur with inhalation of tobramycin inhalation solution. Treat as medically appropriate, if it occurs. ( 5.1 ) Ototoxicity: Tinnitus and hearing loss have been reported in patients receiving tobramycin inhalation solution. If noted, manage as medically appropriate, including potentially discontinuing tobramycin inhalation solution. ( 5.2 ) Nephrotoxicity: Has been associated with aminoglycosides as a class. If nephrotoxicity develops, manage the patient as medically appropriate, including potentially discontinuing tobramycin inhalation solution. ( 5.3 )
Neuromuscular
Disorders: Aminoglycosides may aggravate muscle weakness because of a potential curare‐like effect on neuromuscular function. If neuromuscular blockade occurs, it may be reversed by the administration of calcium salts but mechanical assistance may be necessary. ( 5.4 ) Embryo-fetal Toxicity: Aminoglycosides can cause fetal harm ( 5.5 , 8.1 )
5.1 Bronchospasm Bronchospasm can occur with inhalation of tobramycin inhalation solution. In clinical studies with tobramycin inhalation solution, changes in FEV 1 measured after the inhaled dose were similar in tobramycin inhalation solution and placebo groups. Bronchospasm that occurs during the use of tobramycin inhalation solution should be treated as medically appropriate.
5.2 Ototoxicity with use of Tobramycin inhalation solution Ototoxicity, manifested as both auditory and vestibular toxicity, has been reported with parenteral aminoglycosides. Transient tinnitus occurred in eight tobramycin inhalation solution treated patients versus no placebo patients in the clinical studies. Tinnitus may be a sentinel symptom of ototoxicity, and therefore the onset of this symptom warrants further clinical investigation. Ototoxicity, as measured by complaints of hearing loss or by audiometric evaluations, did not occur with tobramycin inhalation solution therapy during clinical studies, however in postmarketing experience, patients receiving tobramycin inhalation solution have reported hearing loss. Vestibular toxicity may be manifested by vertigo, ataxia or dizziness. Patients with known or suspected auditory or vestibular dysfunction should be closely monitored when taking tobramycin inhalation solution. Monitoring might include obtaining audiometric evaluations and serum tobramycin levels. If ototoxicity is noted, the patient should be managed as medically appropriate, including potentially discontinuing tobramycin inhalation solution. Risk of Ototoxicity Due to Mitochondrial DNA Variants Cases of ototoxicity with aminoglycosides have been observed in patients with certain variants in the mitochondrially encoded 12S rRNA gene (MT-RNR1), particularly the m.1555A>G variant. Ototoxicity occurred in some patients even when their aminoglycoside serum levels were within the recommended range. Mitochondrial DNA variants are present in less than 1% of the general US population, and the proportion of the variant carriers who may develop ototoxicity as well as the severity of ototoxicity is unknown. In case of known maternal history of ototoxicity due to aminoglycoside use or a known mitochondrial DNA variant in the patient, consider alternative treatments other than aminoglycosides unless the increased risk of permanent hearing loss is outweighed by the severity of infection and lack of safe and effective alternative therapies.
5.3 Nephrotoxicity Nephrotoxicity was not seen during clinical studies with tobramycin inhalation solution but has been associated with aminoglycosides as a class. Patients with known or suspected renal dysfunction or taking concomitant nephrotoxic drugs along with tobramycin inhalation solution should have serum concentrations of tobramycin and laboratory measurements of renal function obtained at the discretion of the treating physician. If nephrotoxicity develops, the patient should be managed as medically appropriate, including potentially discontinuing tobramycin inhalation solution.
5.4 Neuromuscular Disorders Aminoglycosides, including tobramycin, may aggravate muscle weakness because of a potential curare-like effect on neuromuscular function. Neuromuscular blockade, respiratory failure, and prolonged respiratory paralysis may occur more commonly in patients with underlying neuromuscular disorders, such as myasthenia gravis or Parkinson’s disease. Prolonged respiratory paralysis may also occur in patients receiving concomitant neuromuscular blocking agents. If neuromuscular blockade occurs, it may be reversed by the administration of calcium salts but mechanical assistance may be necessary.
5.5 Embryo-fetal Toxicity Aminoglycosides can cause fetal harm when administered to a pregnant woman. Aminoglycosides cross the placenta, and streptomycin has been associated with several reports of total, irreversible, bilateral congenital deafness in pediatric patients exposed in utero. However, systemic absorption of tobramycin following inhaled administration is expected to be minimal <span class="opacity-50 text-xs">[see Clinical Pharmacology ( 12.3 ) ]</span>. Patients who use tobramycin inhalation solution during pregnancy, or become pregnant while taking tobramycin inhalation solution should be apprised of the potential hazard to the fetus <span class="opacity-50 text-xs">[see Use in Specific Populations ( 8.1 ) ]</span>.
5.6 Concomitant Use of Systemic Aminoglycosides Patients receiving concomitant tobramycin inhalation solution and parenteral aminoglycoside therapy should be monitored as clinically appropriate for toxicities associated with aminoglycosides as a class. Serum tobramycin levels should be monitored.
5.1 Bronchospasm Bronchospasm can occur with inhalation of tobramycin inhalation solution. In clinical studies with tobramycin inhalation solution, changes in FEV 1 measured after the inhaled dose were similar in tobramycin inhalation solution and placebo groups. Bronchospasm that occurs during the use of tobramycin inhalation solution should be treated as medically appropriate.
5.2 Ototoxicity with use of Tobramycin inhalation solution Ototoxicity, manifested as both auditory and vestibular toxicity, has been reported with parenteral aminoglycosides. Transient tinnitus occurred in eight tobramycin inhalation solution treated patients versus no placebo patients in the clinical studies. Tinnitus may be a sentinel symptom of ototoxicity, and therefore the onset of this symptom warrants further clinical investigation. Ototoxicity, as measured by complaints of hearing loss or by audiometric evaluations, did not occur with tobramycin inhalation solution therapy during clinical studies, however in postmarketing experience, patients receiving tobramycin inhalation solution have reported hearing loss. Vestibular toxicity may be manifested by vertigo, ataxia or dizziness. Patients with known or suspected auditory or vestibular dysfunction should be closely monitored when taking tobramycin inhalation solution. Monitoring might include obtaining audiometric evaluations and serum tobramycin levels. If ototoxicity is noted, the patient should be managed as medically appropriate, including potentially discontinuing tobramycin inhalation solution. Risk of Ototoxicity Due to Mitochondrial DNA Variants Cases of ototoxicity with aminoglycosides have been observed in patients with certain variants in the mitochondrially encoded 12S rRNA gene (MT-RNR1), particularly the m.1555A>G variant. Ototoxicity occurred in some patients even when their aminoglycoside serum levels were within the recommended range. Mitochondrial DNA variants are present in less than 1% of the general US population, and the proportion of the variant carriers who may develop ototoxicity as well as the severity of ototoxicity is unknown. In case of known maternal history of ototoxicity due to aminoglycoside use or a known mitochondrial DNA variant in the patient, consider alternative treatments other than aminoglycosides unless the increased risk of permanent hearing loss is outweighed by the severity of infection and lack of safe and effective alternative therapies.
5.3 Nephrotoxicity Nephrotoxicity was not seen during clinical studies with tobramycin inhalation solution but has been associated with aminoglycosides as a class. Patients with known or suspected renal dysfunction or taking concomitant nephrotoxic drugs along with tobramycin inhalation solution should have serum concentrations of tobramycin and laboratory measurements of renal function obtained at the discretion of the treating physician. If nephrotoxicity develops, the patient should be managed as medically appropriate, including potentially discontinuing tobramycin inhalation solution.
5.4 Neuromuscular Disorders Aminoglycosides, including tobramycin, may aggravate muscle weakness because of a potential curare-like effect on neuromuscular function. Neuromuscular blockade, respiratory failure, and prolonged respiratory paralysis may occur more commonly in patients with underlying neuromuscular disorders, such as myasthenia gravis or Parkinson’s disease. Prolonged respiratory paralysis may also occur in patients receiving concomitant neuromuscular blocking agents. If neuromuscular blockade occurs, it may be reversed by the administration of calcium salts but mechanical assistance may be necessary.
5.5 Embryo-fetal Toxicity Aminoglycosides can cause fetal harm when administered to a pregnant woman. Aminoglycosides cross the placenta, and streptomycin has been associated with several reports of total, irreversible, bilateral congenital deafness in pediatric patients exposed in utero. However, systemic absorption of tobramycin following inhaled administration is expected to be minimal <span class="opacity-50 text-xs">[see Clinical Pharmacology ( 12.3 ) ]</span>. Patients who use tobramycin inhalation solution during pregnancy, or become pregnant while taking tobramycin inhalation solution should be apprised of the potential hazard to the fetus <span class="opacity-50 text-xs">[see Use in Specific Populations ( 8.1 ) ]</span>.
5.6 Concomitant Use of Systemic Aminoglycosides Patients receiving concomitant tobramycin inhalation solution and parenteral aminoglycoside therapy should be monitored as clinically appropriate for toxicities associated with aminoglycosides as a class. Serum tobramycin levels should be monitored.