bethkis

Important safety information

Caution should be exercised when prescribing BETHKIS to patients with known or suspected auditory, vestibular, renal, or neuromuscular dysfunction. ( 5.1 , 5.2 , 5.3 and 5.5 ) Aminoglycoside may aggravate muscle weakness because of a potential curare-like effect on neuromuscular function. ( 5.3 ) Bronchospasm can occur with inhalation of BETHKIS. ( 5.4 ) Audiograms, serum concentration, and renal function should be monitored as appropriate. ( 5.2 and 5.5 ) Fetal harm can occur when aminoglycosides are administered to a pregnant woman. Apprise women of the potential hazard to the fetus. ( 5.6 ) 5.1 Ototoxicity Ototoxicity with use of BETHKIS Caution should be exercised when prescribing BETHKIS to patients with known or suspected auditory or vestibular dysfunction. Findings related to ototoxicity as measured by audiometric evaluations and auditory adverse event reports were similar between BETHKIS and placebo in controlled clinical trials. Hearing loss was reported in two (1.1%) BETHKIS-treated patients and in one (0.9%) placebo-treated patient during clinical studies. Additionally, dizziness and vertigo, both of which may be manifestations of vestibular forms of ototoxicity, were observed in similar numbers of BETHKIS- and placebo-treated patients. Dizziness occurred in two (1.1%) BETHKIS-treated patients and one (0.9%) placebo-treated patient and vertigo occurred in two (1.1%) BETHKIS-treated patients versus no placebo patients in clinical studies. None of the BETHKIS patients discontinued their therapy due to hearing loss, dizziness or vertigo. Tinnitus may be a sentinel symptom of ototoxicity. No reports of tinnitus occurred in patients during clinical studies with BETHKIS, but because it has been observed with inhaled tobramycin solutions [see Adverse Reactions ( 6.2 )] , onset of this symptom warrants caution. Ototoxicity, manifested as both auditory and vestibular toxicity, has been reported with parenteral aminoglycosides. 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 BETHKIS. Monitoring may include obtaining audiometric evaluations and serum tobramycin levels. If ototoxicity is noted, the patient should be managed as medically appropriate, including potentially discontinuing BETHKIS. 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. 5.2 Nephrotoxicity Caution should be exercised when prescribing BETHKIS to patients with known or suspected renal dysfunction. Nephrotoxicity was not seen during BETHKIS clinical studies but has been associated with aminoglycosides as a class. Patients with known or suspected renal dysfunction or taking concomitant nephrotoxic drugs along with BETHKIS 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 BETHKIS until serum concentrations fall below 2 mcg/mL. Twenty-six (14%) BETHKIS patients and 15 (13%) placebo patients had increases in serum creatinine of at least 50% over baseline. Follow-up values were obtained for 17 of the 26 BETHKIS patients, all of which decreased to serum creatinine values that were within normal laboratory ranges. Patients who experience an increase in serum creatinine during treatment with BETHKIS should have their renal function closely monitored. 5.3 Neuromuscular Disorders BETHKIS should be used cautiously in patients with muscular 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. 5.4 Bronchospasm Bronchospasm has been reported with inhalation of tobramycin. In clinical studies with BETHKIS, bronchospasm was observed in one (0.5%) BETHKIS-treated patient and in no placebo-treated patients. Wheezing occurred in ten (5%) BETHKIS-treated patients and four (4%) placebo-treated patients. Bronchospasm and wheezing should be treated as medically appropriate. 5.5 Laboratory Tests Audiograms Clinical studies of inhaled tobramycin solutions did not identify hearing loss using audiometric tests which evaluated hearing up to 8000 Hz. Physicians should consider an audiogram for patients who show any evidence of auditory dysfunction, or who are at increased risk for auditory dysfunction. Tinnitus may be a sentinel symptom of ototoxicity, and therefore the onset of this symptom warrants caution. Serum Concentrations In patients with normal renal function treated with BETHKIS, serum tobramycin concentrations range from approximately 0.06-1.89 mcg/mL one hour after dose administration and do not require routine monitoring. Serum concentrations of tobramycin in patients with renal dysfunction or patients treated with concomitant parenteral tobramycin should be monitored at the discretion of the treating physician [see Clinical Pharmacology ( 12.3 )] . The serum concentration of tobramycin should only be monitored through venipuncture and not finger prick blood sampling. Contamination of the skin of the fingers with tobramycin may lead to falsely increased measurements of serum levels of the drug. This contamination cannot be completely avoided by hand washing before testing. Renal Function The clinical studies of BETHKIS did not reveal any imbalance in the percentage of patients who experienced at least a 50% rise in serum creatinine from baseline in either the BETHKIS group (n=26, 14%) or the placebo group (n=15, 13%). Laboratory tests of urine and renal function should be conducted at the discretion of the treating physician. 5.6 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 [see Clinical Pharmacology ( 12.3 )] . Patients who use BETHKIS during pregnancy, or become pregnant while taking BETHKIS should be apprised of the potential hazard to the fetus [see Use in Specific Populations ( 8.1 )] . 5.7 Concomitant Use of Systemic Aminoglycosides Patients receiving concomitant BETHKIS and parenteral aminoglycoside therapy should be monitored as clinically appropriate for toxicities associated with aminoglycosides as a class. Serum tobramycin levels should be monitored.