Duo-Medihaler

• 3M Pharmaceuticals

Inhalation Aerosol

PHARMACIST: Tear off ‘Patient Instructions for Use” and dispense with product.

Duo-Medihaler is indicated for the treatment of bronchospasm associated with acute and chronic asthma and reversible broncho­spasm which may be associated with chronic bronchitis or emphysema.

General: As with all sympathomimetic drugs, Duo-Medihaler should be used with great caution in the presence of coronary insufficiency, hypertension, hyperthyroidism, and diabetes.

Information for Patients: Patients who are being treated with DUO­-MEDIHALER should be informed adequately of the dangers of overusage, tolerance and rebound bronchospasm (see WARNINGS and ADVERSE REACTIONS sections). They should be instructed to take no more than two inhalations at any one time, nor more than six in any one hour during a 24-hour period, unless advised by the physician (see DOSAGE AND ADMINISTRATION and Patient Instructions for Use sections).

Isoproterenol may cause the patient's saliva to turn pinkish to red in color. Proper use of Duo-Medihaler oral inhaler should be demonstrated and discussed. Patient Instructions for Use are available with the package insert and should be provided when the medication is dispensed.

As with any drug, patients should be advised against the ingestion of alcohol during treatment.

Drug Interactions: A monoamine oxidase (MAO) inhibitor, a tricyclic antidepressant, or guanethidine may increase the cardiac and pressor effects of phenylephrine and isoproterenol; however, normal volunteers given isoproterenol by inhalation along with an MAO inhibitor or a tricyclic antidepressant had no adverse cardio­vascular effects.

Arrhythmias may result from the concurrent administration of isoproterenol or phenylephrine to patients who are receiving digitalis, epinephrine, cyclopropane, or halogenated hydrocarbon anesthetics.

Beta-adrenergic blocking drugs such as propranolol antagonize the cardiac, bronchodilating, and vasodilating effects of isoproterenol and the stimulating effects of phenylephrine.

Ergot alkaloids may increase blood pressure in patients receiving iso­proterenol or phenylephrine. Phentolamine mesylate (Regitine®), an alpha-adrenergic blocker, may decrease the pressor response to phenylephrine.

Phenothiazine drugs have some alpha-adrenergic blocking activity and may reduce the pressor effects and duration of action of phenylephrine.

Drug/Laboratory Test Interactions: Isoproterenol causes false elevations of bilirubin as measured in vitro by sequential multiple analyzer. An effect on serum bilirubin determinations in patients receiving the drug has not been determined. One case of surrepti­tious self-administration of a 500 mg subcutaneous dose of isopro­terenol resulted in increased urinary excretion of epinephrine, norepinephrine, and vanilmandelic acid. Isoproterenol inhalation may result in enough absorption of the drug to produce increased values for urinary epinephrine. This effect is probably small with standard doses, but is likely to increase with larger doses.

Carcinogencity, Mutagenesis, and Impairment of Fertility: Isoproterenol hydrochloride, phenylephrine bitartrate, or DUO-­MEDIHALER have not been evaluated for carcinogenicity, muta­genicity or impairment of fertility.

Pregnancy: Teratogenic Effects - Pregnancy Category C: Repro­duction studies have not been done with Duo-Medihaler or phenylephrine. Reproduction studies with isoproterenol have been performed in rats and rabbits with aerosol doses (30 minutes per day for 12 days) up to 15 times the human dose and have revealed no evidence of impaired fertility or harm to the fetus. It is also not known whether Duo-Medihaler can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Duo-Medihaler should be given to a pregnant woman only if clearly needed.

Labor and Delivery: Duo-Medihaler has no recognized use during labor and delivery. Phenylephrine administration during late pregnancy or labor may cause fetal anoxia and bradycardia by increasing uterine contractility and decreasing uterine blood flow.

Nursing Mothers: It is not known whether isoproterenol or phenyl­ephrine is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when DUO­MEDIHALER is administered to a nursing woman.

Pediatric Use: Safe and effective use of Duo-Medihaler in children below the age of 12 has not been established.

Geriatric Use: Lower doses in elderly patients may be required due to increased sympathomimetic sensitivity (see DOSAGE AND ADMINISTRATION).

Drug abuse and dependence have not been reported with DUO­-MEDIHALER.

Duo-Medihaler is an aerosol device which delivers 0.16 mg of isoproterenol hydrochloride and 0.24 mg of phenylephrine bitar­trate through the oral adapter with each depression of the valve.

15-ml vial and oral adapter, containing 21.0 gm, a minimum of 300 actuations

NDC 0089-0735-21).

15-ml refill vial only, containing 21.0 gm, a minimum of 300 actu­ations (NDC 0089-0735-11).

Note: The indented statement below is required by the Federal government's Clean Air Act for all products containing or manu­factured with chlorofluorocarbons (CFC's).

WARNING: Contains trichloromonofluoromethane, dichlorodifluoromethane, and dichlorotetrafluoroethane, substances which harm public health and environment by destroying ozone in the upper atmosphere.

A notice similar to the above WARNING has been placed in the "Patient Instructions for Use" of this product pursuant to EPA regulations.