PRECAUTIONS
General: Albuterol, as with all sympathomimetic amines, should be used
with caution in patients with cardiovascular disorders, especially coronary
insufficiency, cardiac arrhythmias, and hypertension; in patients with convulsive
disorders, hyperthyroidism, or diabetes mellitus; and in patients who are unusually
responsive to sympathomimetic amines. Clinically significant changes in systolic
and diastolic blood pressure have been seen and could be expected to occur in
some patients after use of any beta-adrenergic bronchodilator.
In controlled clinical trials in adults, patients treated with albuterol extended-release tablets had increases in selected serum chemistry values and decreases in selected hematologic values. Increases in SGPT were more frequent among patients treated with albuterol extended-release tablets (12 of 247 patients, 4.9%) than among the theophylline (6 of 188 patients, 3.2%) and placebo (1 of 138 patients, 0.7%) groups. Increases in serum glucose concentration were also more frequent among patients treated with albuterol extended-release tablets (23 of 234 patients, 9.8%) than among theophylline (11 of 173 patients, 6.45%) and placebo (3 of 129 patients, 2.3%) groups. Increases in SGOT were also more frequent among patients treated with albuterol extended-reIease tablets (10 of 248 patients, 4%) and theophylline (5 of 193, 2.6%) than among patients treated with placebo. Decreases in white blood cell counts were more frequent in patients treated with albuterol extended-release tablets (10 of 247 patients, 4%) compared with patients receiving theophylline (2 of 185 patients, 1.1%) and patients receiving placebo (1 of 141 patients, 0.7%). Decreases in hemoglobin and hematocrit were more frequent in patients receiving albuterol extended-release tablets (16 of 228 patients, 7.0%, and 17 of 230 patients, 7.4%, respectively) than in patients receiving theophylline (5 of 171 patients, 2.9%, and 9 of 173 patients, 5.2%, respectively) and patients receiving placebo (5 of 129 patients, 3.9%, and 3 of 132 patients, 2.3%, respectively). The clinical significance of these results is unknown.
Large doses of intravenous albuterol have been reported to aggravate pre-existing diabetes mellitus and ketoacidosis. As with other beta-agonists, albuterol may produce significant hypokalemia in some patients, possibly through intracellular shunting, which has the potential to produce adverse cardiovascular effects. The decrease is usually transient, not requiring supplementation.
Carcinogenesis, Mutagenesis, Impairment Of Fertility: In a 2-year study
in Sprague-Dawley rats, albuterol sulfate caused a significant dose-related
increase in the incidence of benign leiomyomas of the mesovarium at dietary
doses of 2.0, 10, and 50 mg/kg, (approximately 1/2, 3, and 15 times, respectively,
the maximum recommended daily oral dose for adults on a mg/m2 basis, or, approximately
2/5, 2, and 10 times, respectively, the maximum recommended daily oral dose
for children on a mg/m2 basis). In another study this effect was blocked by
the coadministration of propranolol, a non-selective beta-adrenergic antagonist.
In an 18 month study in CD-1 mice, albuterol sulfate showed no evidence of tumorigenicity
at dietary doses of up to 500 mg/kg (approximately 65 times the maximum recommended
daily oral dose for adults on a mg/m2 basis, or, approximately 50
times the maximum recommended daily oral dose for children on a mg/m2 basis).
In a 22 month study in the Golden hamster, albuterol sulfate showed no evidence
of tumorigenicity at dietary doses of 50 mg/kg, (approximately 7 times the maximum
recommended daily oral dose for adults and children on a mg/m2 basis).
Albuterol sulfate was not mutagenic in the Ames test with or without metabolic
activation using tester strains S. typhimurium TA 1537, TA 1538, and
TA98 or E. coli WP2, WP2uvrA, and WP67. No forward mutation was seen
in yeast strainS. cerevisiae S9 nor any mitotic gene conversion in yeast
strain S. cerevisiae JD1 with or without metabolic activation. Fluctuation
assays in S. typhimurium TA98 and E. coli WP2, both with metabolic
activation, were negative. Albuterol sulfate was not clastogenic in a human
peripheral lymphocyte assay or in an AH1 strain mouse micronucleus assay at
intraperitoneal doses of up to 200 mg/kg.
Reproduction studies in rats demonstrated no evidence of impaired fertility
at oral doses up to 50 mg/kg, (approximately 15 times the maximum recommended
daily oral dose for adults on a mg/m2 basis).
Pregnancy: Teratogenic Effects: Pregnancy Category C: Albuterol Sulfate
has been shown to be terato-genic in mice. A study in CD-1 mice at subcutaneous
(SC) doses of 0.025, 0.25, and 2.5 mg/kg, (approximately 3/1000, 3/100, and
3/10 times the maximum recommended daily oral dose for adults on a mg/m2 basis),
showed cleft palate formation in 5 of 111 (4.5%) fetuses at 0.25 mg/kg and in
10 of 108 (9.3%) fetuses at 2.5 mg/kg. The drug did not induce cleft palate
formation at the lowest dose, 0.025 mg/kg. Cleft palate also occurred in 22
of 72 (30.5%) fetuses of females treated with 2.5 mg/kg, of isoproterenol (positive
control) subcutaneously (approximately 3/10 times the maximum recommended daily
oral dose for adults on a mg/m2 basis). A reproduction study in Stride
Dutch rabbits revealed cranioschisis in 7/19 fetuses (37%) when albuterol sulfate
was administered orally at a 50 mg/kg dose, (approximately 25 times the maximum
recommended daily oral dose for adults on a mg/m2 basis).
There are no adequate and well-controlled studies in pregnant women. Albuterol should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
During worldwide marketing experience, various congenital anomalies, including cleft palate and limb defects, have been rarely reported in the offspring of patients being treated with albuterol. Some of the mothers were taking multiple medications during their pregnancies. No consistent pattern of defects can be discerned, and a relationship between albuterol use and congenital anomalies has not been established.
Labor and Delivery: Because of the potential for beta-agonist interference
with uterine contractility, use of albuterol extended-release tablets for relief
of bronchospasm during labor should be restricted to those patients in whom
the benefits clearly outweigh the risks.
Tocolysis: Albuterol has not been approved for the management of pre-term
labor. The benefit:risk ratio when albuterol is administered for tocolysis has
not been established. Serious adverse reactions, including pul- monary edema,
have been reported during or following treatment of premature labor with beta2-agonists,
including albuterol.
Nursing Mothers: It is not known whether albuterol is excreted in human
milk. Because of the potential for tumorigenicity shown for albuterol in animal
studies, a decision should be made whether to discontinue nursing or to discontinue
the drug, taking into account the importance of the drug to the mother.
Pediatric Use: The safety and effectiveness of albuterol extended-release
tablets have been established in pediatric patients 6 years of age or older.
Use of albuterol extended-release tablets in these age groups is supported by
evidence from adequate and well-controlled studies of albuterol extended-release
tablets in adults; the likelihood that the disease course, pathophysiology,
and the drug's effect in pediatric and adult patients are substantially similar;
the established safety and effectiveness of immediate release albuterol tablets
in pediatric patients 6 years of age and older; and clinical trials that support
the safety of albuterol extended-release tablets in pediatric patients over
6 years of age. The recommended dose of albuterol extended-release tablets for
the pediatric population is based upon the recommended pediatric dosing of immediate-release
albuterol tablets and pharmacokinetic studies in adults showing comparable bioavailability
at steadystate dosing and reduced bioavailability after single dose administration.
Safety and effectiveness in pediatric patients below 6 years of age have not
been established.