Metaproterenol Sulfate

 Actions Relaxes bronchial smooth muscle through beta-2 receptor stimulation.

 Indications Treatment of bronchial asthma and reversible bronchospasm associated with bronchitis and emphysema; control of acute asthma attacks in children ³ 6 yr (inhalation solution only).

 Contraindications Cardiac arrhythmias associated with tachycardia.

 Route/Dosage

Aerosol

ADULTS AND CHILDREN ³ 12 yr: Inhalation 2 to 3 inhalations q 3 to 4 hr, not to exceed 12 inhalations/day.

Hand Nebulizer

ADULTS AND CHILDREN ³ 12 yr: Inhalation 5 to 15 inhalations q 4 hr prn.

Intermittent Positive Pressure Breathing Apparatus

ADULTS AND CHILDREN ³ 12 yr: Inhalation 0.2 to 0.3 mL of 5% solution in 2.5 mL of diluent q 4 hr prn.

Nebulizer

ADULTS AND CHILDREN ³ 12 yr: Inhalation 0.1 to 0.2 mL in saline to a total volume of 3 mL.

 Interactions

MAOIs, Tricyclic Antidepressants: Pressor effects may be potentiated.

 Lab Test Interferences None well documented.

 Adverse Reactions

CARDIOVASCULAR: Palpitations; hypertension; tachycardia; cardiac arrest; palpitations; tachycardia; blood pressure changes/hypertension. CNS: Tremor; dizziness; nervousness; weakness; headache; shakiness/nervousness/tension; drowsiness; insomnia. DERMATOLOGIC: Rash. EENT: Throat irritation; bad taste; taste/smell change. GI: GI distress; nausea; vomiting; dry mouth. RESPIRATORY: Cough; asthma exacerbation; throat dryness/irritation; pharyngitis; asthma exacerbation; hoarseness; nasal congestion. OTHER: Fatigue; skin reaction.

 Precautions

Pregnancy: Category C. Lactation: Undetermined. CHILDREN: May be used in children ³ 6 yrs. Elderly: Lower doses may be required. CNS Effects: CNS stimulation may occur; use drug with caution in patients with history of seizures or hypothyroidism. Cardiovascular Disorders: Toxic symptoms may occur. Diabetes Mellitus: Dosage adjustment of insulin or oral hypoglycemic agent may be required. Excessive Use: Paradoxical bronchospasm and cardiac arrest have been associated with excessive inhalant use. Hypersensitivity: Hypersensitivity (allergic) reactions can occur after administration. Labor and Delivery: May inhibit uterine contractions and delay preterm labor. Tolerance: May occur.

 Administration/Storage

• Oral form may be given with food to minimize GI upset.
• Instruct patient to exhale through nose as completely as possible; tilt head back, and put inhaler mouthpiece between lips or 2 inches from open mouth. Tell patient to inhale slowly, press down on cannister, hold breath ³ 10 sec or as long as comfortable, then exhale slowly.
• Administer pressurized inhalation during second half of inspiration to achieve better distribution of medication. Instruct patient to wait ³ 2 full min between inhalations.
• Store metered-dose inhaler in pressurized container at room temperature; do not freeze. Keep away from extreme heat. Do not use near open flame or discard in incinerator.
• Refrigerate unit dose nebulizer vials at 35° to 46°F. Protect from excessive heat and light.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies.
• Review baseline ECG for cardiac dysrhythmias associated with tachycardia.
• Obtain baseline blood values and monitor during therapy. Notify health care provider of abnormal results.
• Take vital signs before, during, and after treatment, noting elevations in BP and pulse. If tachycardia, cardiac arrhythmia or chest pain are present, withhold medication and notify health care provider immediately.
• Assess baseline respiratory function, vital capacity and forced expiratory volume.
• Auscultate lung sounds before and after treatment. If increase in extra sounds, notify health care provider.
• Observe for signs of tremors and anxiety. If present, discontinue therapy and notify health care provider.
• Have epinephrine 1:1000 available for immediate or delayed hypersensitivity reaction.

 Patient/Family Education

• Ask patient to demonstrate correct use of inhaler. It may be necessary to repeat instructions and demonstrations more than once.
• Instruct patient that if > 1 inhalation is necessary, to wait ³ 2 min between doses.
• Instruct patient to wash and dry inhaler every day in warm water.
• Explain that tolerance may occur with prolonged use, but temporary cessation of drug usually restores its original effectiveness. Instruct patient to notify health care provider if medication is ineffective.
• Warn patient to avoid excessive use (£ q 4 hr), which can lead to side effects or loss of effectiveness.
• Advise patient to increase fluid intake to liquefy secretions.
• Instruct patient to report the following symptoms to health care provider: palpitations, nervousness, dizziness, shortness of breath, rash, asthma exacerbation.
• Caution patient to avoid getting aerosol medication in eyes.
• Advise patient to avoid smoke-filled rooms and smoking.
• Instruct patient not to take otc medications without consulting health care provider.
• Instruct patient to rinse mouth with water after each use.