Medihaler-Iso

• 3M Pharmaceuticals

Medihaler-Iso (isoproterenol sulfate) is a short-acting sympathomimetic administered by oral inhalation for the treatment of bronchoconstriction. Each metered dose of the aerosol delivers through the oral adapter 0.08 mg isoproterenol sulfate of appropriate particle size (the majority less than 5μ). This drug product also contains dichlorodifluoromethane, dichlorotetrafluoroethane, sorbitan trioleate, and trichloromonofluoromethane. Chemically, isoproterenol sulfate is 4-[1-hyroxy-2-[(1-methylethyl)amino]ethyl]-1,2-benzenediol sulfate.

Structural formula:

The following adverse effects, listed by organ system in decreasing frequency have been associated with the use of Medihaler-Iso and are similar to those produced by other sympathomimetic agents:

Cardiovascular: Palpitation, tachycardia, coronary insufficiency, flushing of the skin, blood pressure changes, cardiac arrhythmias, anginal pain, cardiac arrest.

Pulmonary: Paradoxical airway resistance (see WARNINGS), rebound bronchospasm.

Central Nervous System: Headache, tremor, vertigo, central excitation, insomnia.

Gastrointestinal: Nausea.

The oral LD50 values for isoproterenol are as follows: mouse, 1260 mg/kg: rabbit, 3070 mg/kg; male rat, 2230 mg/kg; female rat, 2840 mg/kg; and dog, 600 mg/kg. The intravenous LD50 values are as follows: mouse, 126 mg/kg; rabbit, 27 mg/kg; male rat, 96 mg/kg; female rat, 112 mg/kg; and dog, 50 mg/kg.

Overdosage effects may occur at doses equal to the therapeutic dose.

Symptoms: Manifestations of acute overdosage include chest pain, dizziness, headache, irregular heartbeat, fast or pounding heartbeat, nausea or vomiting, restlessness, weakness, flushing, or decreased diastolic pressure.

Treatment: Discontinued dosing allows rapid reversal of adverse effects. Blood pressure and ECG may be monitored and the following treatment used, as appropriate: tachycardia in asthmatic patients may be treated with cardio-selective beta-blockers (metoprolol or atenolol, but used cautiously since cardio-selectivity may not be absolute) and in nonasthmatics with propranolol; blood pressure may be regulated with rapid-acting vasodilators (nitrites, sodium nitroprusside) or alpha-blocking agents (quinidine, phentolamine).

It is not known if isoproterenol is dialyzable; however, its rapid elimination should preclude the need for dialysis.

Adults: The usual dose for the relief of dyspnea in the acute episode is one or two inhalations. Start with a single inhalation. If no relief is evident after two to five minutes, a second inhalation may be taken. For daily maintenance, use one or two inhalations four to six times daily or as directed by the physician. The physician should be careful to instruct the patient in the proper technique of administration so that the number of inhalations per treatment and the frequency of retreatment may be titrated to the patient's response.

No more than two inhalations should be taken at any one time, nor more than six inhalations in any one hour during a 24-hour period, unless advised by the physician. Lower doses in elderly patients may be required due to increased sympathomimetic sensitivity.

Each depression of the valve delivers through the oral adapter 0.08 mg isoproterenol sulfate.

Children: Safety and effectiveness for children under 12 years have not been established (see Pediatric Use).

Before each use, remove dust cap and inspect mouthpiece for foreign objects. Shake Medihaler-Iso.

1. Breathe out fully and place mouthpiece well into the mouth aimed at the back of the throat.
2. As you begin to breathe in deeply, press the vial firmly down into the adapter with the index finger. This releases one dose.
3. Release pressure on vial and remove unit from mouth. Hold your breath as long as possible, then breathe out slowly.

Replace dust cap after each use.