Albuterol Sulfate - Albuterol Sulfate tablet prescribing information
INDICATIONS AND USAGE
Albuterol tablets are indicated for the relief of bronchospasm in adults and children 6 years of age and older with reversible obstructive airway disease.
DOSAGE AND ADMINISTRATION
The following dosages of albuterol tablets are expressed in terms of albuterol base.
Usual Dosage
Adults and Children Over 12 Years of Age
The usual starting dosage for adults and children 12 years and older is 2 or 4 mg three or four times a day.
Children 6 to 12 Years of Age
The usual starting dosage for children 6 to 12 years of age is 2 mg three or four times a day.
Dosage Adjustment
Adults and Children Over 12 Years of Age
For adults and children 12 years and older, a dosage above 4 mg four times a day should be used only when the patient fails to respond. If a favorable response does not occur with the 4 mg initial dosage, it should be cautiously increased stepwise up to a maximum of 8 mg four times a day as tolerated.
Children 6 to 12 Years of Age Who Fail to Respond to the Initial Starting Dosage of 2 mg Four Times a Day
For children from 6 to 12 years of age who fail to respond to the initial starting dosage of 2 mg four times a day, the dosage may be cautiously increased stepwise, but not to exceed 24 mg/day (given in divided doses).
Elderly Patients and Those Sensitive to Beta-adrenergic Stimulators
An initial dosage of 2 mg three or four times a day is recommended for elderly patients and for those with a history of unusual sensitivity to beta-adrenergic stimulators. If adequate bronchodilation is not obtained, dosage may be increased gradually to as much as 8 mg three or four times a day.
The total daily dose should not exceed 32 mg in adults and children 12 years and older.
CONTRAINDICATIONS
Albuterol tablets are contraindicated in patients with a history of hypersensitivity to albuterol, or any of its components.
ADVERSE REACTIONS
In clinical trials, the most frequent adverse reactions to albuterol tablets were:
| Reaction | Percent Incidence |
|---|---|
Central nervous system | |
Nervous | 20% |
Tremor | 20% |
Headache | 7% |
Sleeplessness | 2% |
Weakness | 2% |
Dizziness | 2% |
Drowsiness | <1% |
Restlessness | <1% |
Irritability | <1% |
Cardiovascular | |
Tachycardia | 5% |
Palpitations | 5% |
Chest discomfort | <1% |
Flushing | <1% |
Musculoskeletal | |
Muscle cramps | 3% |
Gastrointestinal | |
Nausea | 2% |
Genitourinary | |
Difficulty in micturition | <1% |
Rare cases of urticaria, angioedema, rash, bronchospasm, and oropharyngeal edema have been reported after the use of albuterol.
In addition, albuterol, like other sympathomimetic agents, can cause adverse reactions such as hypertension, angina, vomiting, vertigo, central nervous system stimulation, unusual taste, and drying or irritation of the oropharynx.
The reactions are generally transient in nature, and it is usually not necessary to discontinue treatment with albuterol tablets. In selected cases, however, dosage may be reduced temporarily; after the reaction has subsided, dosage should be increased in small increments to the optimal dosage.
Drug Interactions
The concomitant use of albuterol tablets and other oral sympathomimetic agents is not recommended since such combined use may lead to deleterious cardiovascular effects. This recommendation does not preclude the judicious use of an aerosol bronchodilator of the adrenergic stimulant type in patients receiving albuterol tablets. Such concomitant use, however, should be individualized and not given on a routine basis. If regular coadministration is required, then alternative therapy should be considered.
Monoamine Oxidase Inhibitors or Tricyclic Antidepressants
Albuterol should be administered with extreme caution to patients being treated with monoamine oxidase inhibitors or tricyclic antidepressants, or within 2 weeks of discontinuation of such agents, because the action of albuterol on the vascular system may be potentiated.
Beta-Blockers
Beta-adrenergic receptor blocking agents not only block the pulmonary effect of beta-agonists, such as albuterol tablets, but may produce severe bronchospasm in asthmatic patients. Therefore, patients with asthma should not normally be treated with beta-blockers. However, under certain circumstances, e.g., as prophylaxis after myocardial infarction, there may be no acceptable alternatives to the use of beta-adrenergic blocking agents in patients with asthma. In this setting, cardioselective beta-blockers could be considered, although they should be administered with caution.
Diuretics
The ECG changes and/or hypokalemia that may result from the administration of nonpotassium-sparing diuretics (such as loop or thiazide diuretics) can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is not known, caution is advised in the coadministration of beta-agonists with nonpotassium-sparing diuretics.
Digoxin
Mean decreases of 16% to 22% in serum digoxin levels were demonstrated after single-dose intravenous and oral administration of albuterol, respectively, to normal volunteers who had received digoxin for 10 days. The clinical significance of these findings for patients with obstructive airway disease who are receiving albuterol and digoxin on a chronic basis is unclear. Nevertheless, it would be prudent to carefully evaluate the serum digoxin levels in patients who are currently receiving digoxin and albuterol.
DESCRIPTION
Albuterol tablets contain albuterol sulfate, USP, the racemic form of albuterol and a relatively selective beta 2 -adrenergic bronchodilator. Albuterol sulfate has the chemical name α 1 -[( tert -Butylamino)methyl]-4-hydroxy- m -xylene-α,α'-diol sulfate (2:1)(salt) and the following structural formula:
Albuterol sulfate has a molecular weight of 576.71, and the molecular formula is (C 13 H 21 NO 3 ) 2 •H 2 SO 4 . Albuterol sulfate is a white or practically white powder, freely soluble in water and slightly soluble in ethanol.
The World Health Organization recommended name for albuterol base is salbutamol.
Each albuterol sulfate tablet, for oral administration contains 2 or 4 mg of albuterol as 2.4 or 4.8 mg of albuterol sulfate, respectively. Each tablet also contains the following inactive ingredients: anhydrous lactose, magnesium stearate, pregelatinized (corn) starch, and sodium starch glycolate.
CLINICAL PHARMACOLOGY
In vitro studies and in vivo pharmacologic studies have demonstrated that albuterol has a preferential effect on beta 2 -adrenergic receptors compared with isoproterenol. While it is recognized that beta 2 -adrenergic receptors are the predominant receptors in bronchial smooth muscle, data indicate that there is a population of beta 2 -receptors in the human heart existing in a concentration between 10% and 50%. The precise function of these receptors has not been established (see WARNINGS ).
The pharmacologic effects of beta-adrenergic agonist drugs, including albuterol, are at least in part attributable to stimulation through beta-adrenergic receptors of intracellular adenyl cyclase, the enzyme that catalyzes the conversion of adenosine triphosphate (ATP) to cyclic-3',5'-adenosine monophosphate (cyclic AMP). Increased cyclic AMP levels are associated with relaxation of bronchial smooth muscle and inhibition of release of mediators of immediate hypersensitivity from cells, especially from mast cells.
Albuterol has been shown in most controlled clinical trials to have more effect on the respiratory tract, in the form of bronchial smooth muscle relaxation, than isoproterenol at comparable doses while producing fewer cardiovascular effects.
Albuterol is longer acting than isoproterenol in most patients by any route of administration because it is not a substrate for the cellular uptake processes for catecholamines nor for catechol- O -methyl transferase.
Preclinical
Intravenous studies in rats with albuterol sulfate have demonstrated that albuterol crosses the blood brain barrier and reaches brain concentrations amounting to approximately 5% of the plasma concentrations. In structures outside the brain barrier (pineal and pituitary glands), albuterol concentrations were found to be 100 times those in the whole brain.
Studies in laboratory animals (minipigs, rodents, and dogs) have demonstrated the occurrence of cardiac arrhythmias and sudden death (with histologic evidence of myocardial necrosis) when beta-agonists and methylxanthines are administered concurrently. The clinical significance of these findings is unknown.
Pharmacokinetics
Albuterol is rapidly absorbed after oral administration of one 4 mg albuterol tablet in normal volunteers. Maximum plasma concentrations of about 18 ng/mL of albuterol are achieved within 2 hours, and the drug is eliminated with a half-life of about 5 hours.
In other studies, the analysis of urine samples of patients given 8 mg of tritiated albuterol orally showed that 76% of the dose was excreted over 3 days, with the majority of the dose being excreted within the first 24 hours. Sixty percent of this radioactivity was shown to be the metabolite. Feces collected over this period contained 4% of the administered dose.
Clinical Trials
In controlled clinical trials in patients with asthma, the onset of improvement in pulmonary function, as measured by maximum midexpiratory flow rate (MMEF), was within 30 minutes after a dose of albuterol tablets, with peak improvement occurring between 2 and 3 hours. In controlled clinical trials in which measurements were conducted for 6 hours, clinically significant improvement (defined as maintaining a 15% or more increase in forced expiratory volume in 1 second [FEV 1 ] and a 20% or more increase in MMEF over baseline values) was observed in 60% of patients at 4 hours and in 40% at 6 hours. In other single-dose, controlled clinical trials, clinically significant improvement was observed in at least 40% of the patients at 8 hours. No decrease in the effectiveness of albuterol tablets was reported in patients who received long-term treatment with the drug in uncontrolled studies for periods up to 6 months.
Clinical Trials
In controlled clinical trials in patients with asthma, the onset of improvement in pulmonary function, as measured by maximum midexpiratory flow rate (MMEF), was within 30 minutes after a dose of albuterol tablets, with peak improvement occurring between 2 and 3 hours. In controlled clinical trials in which measurements were conducted for 6 hours, clinically significant improvement (defined as maintaining a 15% or more increase in forced expiratory volume in 1 second [FEV 1 ] and a 20% or more increase in MMEF over baseline values) was observed in 60% of patients at 4 hours and in 40% at 6 hours. In other single-dose, controlled clinical trials, clinically significant improvement was observed in at least 40% of the patients at 8 hours. No decrease in the effectiveness of albuterol tablets was reported in patients who received long-term treatment with the drug in uncontrolled studies for periods up to 6 months.
HOW SUPPLIED
Albuterol tablets, USP; 2 mg of albuterol as the sulfate, are white, round, scored, debossed MP 47
Bottles of 100 | NDC 53489-176-01 |
Bottles of 500 | NDC 53489-176-05 |
Albuterol tablets, USP; 4 mg of albuterol as the sulfate, are white, round, scored, debossed MP 88
Bottles of 100 | NDC 53489-177-01 |
Bottles of 500 | NDC 53489-177-05 |
Store at 20° to 25°C (68° to 77°F).
[See USP Controlled Room Temperature]
DISPENSE IN TIGHT, LIGHT-RESISTANT CONTAINER.
