pirbuterol acetate

pir·bu·ter·ol acetate (pr-byt-rôl, -rl)

n.

An analog of albuterol that acts as a bronchodilator and is used in the treatment of asthma.

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pirbuterol acetate (pirbū´trol´ as´tāt),

n brand name: Maxair;
drug class: bronchodilator;
action: causes bronchodilation with little effect on heart rate by acting on β-receptors, causing increased cAMP and relaxation of smooth muscle;
uses: reversible bronchospasms (prevention, treatment), including asthma, may be given with theophylline or steroids.

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pirbuterol acetate

Maxair Autohaler

Pharmacologic class: Beta-adrenergic agonist

Therapeutic class: Bronchodilator

Pregnancy risk category C

Action

Increases production of cyclic adenosine monophosphate at beta-adrenergic receptors, producing bronchodilation and inhibiting histamine release. Primarily selective for beta₂-adrenergic (pulmonary) receptors, with minimal effect on beta₁-adrenergic (cardiac) receptors.

Availability

Inhalation aerosol: 200 mcg/spray (up to 400 inhalations/14.0-g canister)

⊘Indications and dosages

➣ Reversible airway disease

Adults and children older than age 12: One or two inhalations q 4 to 6 hours (not to exceed 12 inhalations/day)

Contraindications

• Hypersensitivity to drug, adrenergic amines, or fluorocarbons

Precautions

Use cautiously in:
• cardiac disease, hypertension, hyperthyroidism, diabetes mellitus, glaucoma, hypokalemia
• elderly patients
• pregnant (near term) or breastfeeding patients
• children younger than age 12 (safety not established).

Administration

• If patient also uses a corticosteroid inhaler, give pirbuterol first, then wait 5 minutes before giving steroid.

Route	Onset	Peak	Duration
Inhalation	Within 5 min	1.5 hr	6-8 hr

Adverse reactions

CNS: headache, nervousness, restlessness, tremor, insomnia

CV: angina, hypertension, tachycardia, arrhythmias

GI: nausea, vomiting

Metabolic: hyperglycemia

Respiratory: paradoxical bronchospasm

Interactions

Drug-drug. Beta-adrenergic blockers: negation of pirbuterol's therapeutic effects

Diuretics: hypokalemia, exacerbation of ECG changes

MAO inhibitors: hypertensive crisis

Other adrenergics: additive adverse adrenergic effects

Drug-diagnostic tests. Glucose: increased level

Drug-food. Caffeine-containing foods and beverages: increased stimulant effect

Drug-herbs. Caffeine-containing herbs (such as cola nut, guarana, yerba maté), ephedra (ma huang): increased stimulant effect

Patient monitoring

☞ Be aware that excessive use may lead to tolerance and paradoxical bronchospasm.
• Monitor respiratory status before and after administering. Note improvements.
• Assess dosage and dosing frequency needed to control symptoms. Notify prescriber if patient needs higher dosage to control symptoms.
• Assess vital signs and cardiovascular status. Stay alert for angina, hypertension, and arrhythmias.
• Monitor patient for worsening bronchospasm after administration.

Patient teaching

• Teach patient how to use metered-dose inhaler or autoinhaler.
• Instruct patient to wait at least 2 minutes between inhalations.
• If patient also uses inhaled corticosteroid, tell him to use pirbuterol first and then wait 5 minutes before using steroid.
• Advise patient to contact prescriber if he needs higher or more frequent doses to control symptoms.
• Teach patient to recognize signs and symptoms of bronchospasm. Advise him to notify prescriber if these worsen after he takes drug.
• Tell patient that herbs containing ephedra or caffeine may increase stimulant effects, such as nervousness and tremors.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, and herbs mentioned above.