Pirbuterol
Medically reviewed on Nov 15, 2018
Pronunciation
(peer BYOO ter ole)
Index Terms
- Maxair Autohaler
- Pirbuterol Acetate
Pharmacologic Category
- Beta2 Agonist
Pharmacology
Pirbuterol is a beta2-adrenergic agonist with a similar structure to albuterol, specifically a pyridine ring has been substituted for the benzene ring in albuterol. The increased beta2 selectivity of pirbuterol results from the substitution of a tertiary butyl group on the nitrogen of the side chain, which additionally imparts resistance of pirbuterol to degradation by monoamine oxidase and provides a lengthened duration of action in comparison to the less selective beta-agonist agents.
Metabolism
Hepatic (by sulfate conjugation)
Excretion
Urine (10% as unchanged drug; 51% as pirbuterol plus its sulfate conjugate)
Onset of Action
5 minutes; Peak effect: Therapeutic: 0.5 to 1 hour
Duration of Action
5 hours
Half-Life Elimination
~2 hours
Use: Labeled Indications
Prevention and treatment of reversible bronchospasm including asthma
Contraindications
Hypersensitivity to pirbuterol or any component of the formulation
Dosing: Adult
Note: Maxair Autohaler has been discontinued in the US for more than 1 year.
Bronchospasm, prevention and treatment: Inhalation: 1 to 2 inhalations every 4 to 6 hours; not to exceed 12 inhalations daily. Patients should be advised to promptly consult healthcare provider or seek medical attention if no relief from acute treatment
Dosing: Geriatric
Refer to adult dosing.
Dosing: Pediatric
Bronchospasm, prevention and treatment: Children ≥12 years and Adolescents: Inhalation: Refer to adult dosing.
Dosing: Renal Impairment
No dosage adjustment provided in manufacturer’s labeling. However, dosage adjustment unlikely due to low systemic absorption.
Dosing: Hepatic Impairment
No dosage adjustment provided in manufacturer’s labeling. However, dosage adjustment unlikely due to low systemic absorption.
Administration
Inhalation: Metered-dose inhaler: Shake well before use; prime prior to first use, and whenever inhaler has not been used for >48 hours by releasing 2 test sprays into the air (away from face). Inhaler should be cleaned with a clean, dry cloth (mouthpiece) and a dry cotton swab (spray hole) at least once per week.
Storage
Store between 15°C and 30°C (59°F and 86°F).
Drug Interactions
AtoMOXetine: May enhance the tachycardic effect of Beta2-Agonists. Monitor therapy
AtoMOXetine: May enhance the hypertensive effect of Sympathomimetics. AtoMOXetine may enhance the tachycardic effect of Sympathomimetics. Monitor therapy
Atosiban: Beta2-Agonists may enhance the adverse/toxic effect of Atosiban. Specifically, there may be an increased risk for pulmonary edema and/or dyspnea. Monitor therapy
Beta-Blockers (Beta1 Selective): May diminish the bronchodilatory effect of Beta2-Agonists. Of particular concern with nonselective beta-blockers or higher doses of the beta1 selective beta-blockers. Monitor therapy
Beta-Blockers (Nonselective): May diminish the bronchodilatory effect of Beta2-Agonists. Avoid combination
Betahistine: May diminish the therapeutic effect of Beta2-Agonists. Monitor therapy
Cannabinoid-Containing Products: May enhance the tachycardic effect of Sympathomimetics. Exceptions: Cannabidiol. Monitor therapy
Cocaine (Topical): May enhance the hypertensive effect of Sympathomimetics. Management: Consider alternatives to use of this combination when possible. Monitor closely for substantially increased blood pressure or heart rate and for any evidence of myocardial ischemia with concurrent use. Consider therapy modification
Doxofylline: Sympathomimetics may enhance the adverse/toxic effect of Doxofylline. Monitor therapy
Guanethidine: May enhance the arrhythmogenic effect of Sympathomimetics. Guanethidine may enhance the hypertensive effect of Sympathomimetics. Monitor therapy
Linezolid: May enhance the hypertensive effect of Sympathomimetics. Management: Reduce initial doses of sympathomimetic agents, and closely monitor for enhanced pressor response, in patients receiving linezolid. Specific dose adjustment recommendations are not presently available. Consider therapy modification
Loop Diuretics: Beta2-Agonists may enhance the hypokalemic effect of Loop Diuretics. Monitor therapy
Loxapine: Agents to Treat Airway Disease may enhance the adverse/toxic effect of Loxapine. More specifically, the use of Agents to Treat Airway Disease is likely a marker of patients who are likely at a greater risk for experiencing significant bronchospasm from use of inhaled loxapine. Management: This is specific to the Adasuve brand of loxapine, which is an inhaled formulation. This does not apply to non-inhaled formulations of loxapine. Avoid combination
Monoamine Oxidase Inhibitors: May enhance the adverse/toxic effect of Beta2-Agonists. Monitor therapy
Sympathomimetics: May enhance the adverse/toxic effect of other Sympathomimetics. Monitor therapy
Tedizolid: May enhance the hypertensive effect of Sympathomimetics. Tedizolid may enhance the tachycardic effect of Sympathomimetics. Monitor therapy
Thiazide and Thiazide-Like Diuretics: Beta2-Agonists may enhance the hypokalemic effect of Thiazide and Thiazide-Like Diuretics. Monitor therapy
Tricyclic Antidepressants: May enhance the adverse/toxic effect of Beta2-Agonists. Monitor therapy
Adverse Reactions
1% to 10%:
Cardiovascular: Palpitations (2%), tachycardia (1%)
Central nervous system: Nervousness (7%), tremor (6%), headache (2%), dizziness (1%)
Endocrine & metabolic: Decreased serum potassium, increased serum glucose
Gastrointestinal: Nausea (2%)
Respiratory: Cough (1%)
<1%: Abdominal pain, alopecia, altered sense of smell, anorexia, anxiety, bruising, chest pain, confusion, depression, diarrhea, dysgeusia, edema, fatigue, flushing, glossitis, hyperkinesia, hypotension, insomnia, numbness of extremities, pruritus, skin rash, sore throat, stomatitis, syncope, vomiting, weakness, weight gain, xerostomia
Warnings/Precautions
Concerns related to adverse effects:
• Bronchospasm: Rarely, paradoxical bronchospasm may occur with use of inhaled bronchodilating agents (may occur more frequently with the first use of a new canister); this should be distinguished from inadequate response.
Disease-related concerns:
• Asthma: Appropriate use: Optimize anti-inflammatory treatment before initiating maintenance treatment with pirbuterol. Do not use as a component of chronic therapy without an anti-inflammatory agent. Only the mildest forms of asthma (Step 1 and/or exercise-induced) would not require concurrent use based upon asthma guidelines.
• Cardiovascular disease: Use with caution in patients with cardiovascular disease (arrhythmia or hypertension or heart failure); beta-agonists may cause elevation in blood pressure, heart rate and result in CNS stimulation/excitation. Beta2-agonists may also increase risk of arrhythmias.
• Diabetes: Use with caution in patients with diabetes mellitus; beta2-agonists may increase serum glucose.
• Glaucoma: Use with caution in patients with glaucoma; may elevate intraocular pressure.
• Hyperthyroidism: Use with caution in hyperthyroidism; may stimulate thyroid activity.
• Hypokalemia: Use with caution in patients with hypokalemia; beta2-agonists may decrease serum potassium.
• Seizures: Use with caution in patients with seizure disorders; beta-agonists may result in CNS stimulation/excitation.
Other warnings/precautions:
• Appropriate use: Do not exceed recommended dose; serious adverse events, including fatalities, have been associated with excessive use of inhaled sympathomimetics.
• Patient information: Patients must be instructed to seek medical attention in cases where acute symptoms are not relieved or a previous level of response is diminished. The need to increase frequency of use may indicate deterioration of asthma, and treatment must not be delayed. All patients should utilize a spacer device when using a metered-dose inhaler.
Monitoring Parameters
Respiratory rate; FEV1, peak flow, and/or other pulmonary function tests; blood pressure, heart rate; CNS stimulation; serum glucose, serum potassium
Pregnancy Risk Factor
C
Pregnancy Considerations
Adverse events have been observed in some animal reproduction studies. Beta-agonists may interfere with uterine contractility if administered during labor.
Uncontrolled asthma is associated with adverse events on pregnancy (increased risk of perinatal mortality, pre-eclampsia, preterm birth, low birth weight infants). Other beta2-receptor agonists are preferred for the treatment of asthma during pregnancy (NAEPP, 2005).
Further information
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
More about pirbuterol
- Pirbuterol Side Effects
- During Pregnancy or Breastfeeding
- Dosage Information
- Drug Interactions
- 5 Reviews
- Drug class: adrenergic bronchodilators
Consumer resources
Professional resources
Other brands: Maxair, Maxair Autohaler