Duo-Medihaler (Page 2 of 2)


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

Isoproterenol Phenylephrine
Cardio- palpitation bradycardia
vascular: tachycardia decreased cardiac
coronary output
insufficiency blanching of skin
flushing of skin peripheral and
blood pressure visceral vaso-
changes constriction
cardiac arrhythmias cardiac
cardiac arrest irregularities
anginal pain anginal pain
Isoproterenol Phenylephrine
Pulmonary: paradoxical airway respiratory
resistance distress
rebound broncho-
Central Nerv- headache tremor
ous System: tremor dizziness
vertigo central excitation
central excitation pilomotor
insomnia response
Gastro- nausea


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


Isoproterenol: The oral LD50 values 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.

Phenylephrine: The oral LD50 values are as follows: rat, 350 mg/kg; and mouse, 120 mg/kg. The intravenous LD50 values are as follows: rat, 6.8 mg/kg; and mouse, 21 mg/kg.

Symptoms: The individual patient’s sensitivity to either drug will dictate the overdosage signs. There is reason to believe, however, that the overdosage effects of either drug are antagonized by the other drug in the combination. Severe symptoms of overdosage are more likely to result from parenteral administration of isoproterenol rather than from oral inhalation of isoproterenol and phenylephrine in an aerosol.

Manifestations of acute overdosage include chest pain, dizziness, headache, irregular heartbeat, fast or pounding heartbeat, brady­cardia, nausea or vomiting, restlessness, weakness, flushing, decreased diastolic pressure, convulsions, cerebral hemorrhage, or hypertension.

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 cardioselective beta-blockers (meto­prolol or atenolol, but use cautiously since cardioselectivity may not be absolute) and in nonasthmatics with propranolol; brady­cardia may be treated with atropine; blood pressure may be regulated with rapid-acting vasodilators (nitrites, sodium nitro­prusside) or alpha-blocking agents (quinidine, phentolamine). It is not known if isoproterenol or phenylephrine are dialyzable.


Adults: The usual dose for the relief of dyspnea caused by acute bronchospasm 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 0.16 mg isoproterenol hydrochloride and 0.24 mg phenylephrine bitartrate.

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


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

  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.

How supplied

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.


Federal law prohibits dispensing without prescription. CONTENTS UNDER PRESSURE. Do not puncture or incinerate container Store at controlled room temperature between 15°C and 30°C. (59°F and 86°F). KEEP OUT OF THE REACH OF CHILDREN.

3M Pharmaceuticals
Northridge, CA 91324

isoproterenol hydrochloride and phenylephrine bitartrate aerosol, metered
Product Information
Product Type HUMAN PRESCRIPTION DRUG Item Code (Source) NDC:0089-0735
Route of Administration RESPIRATORY (INHALATION) DEA Schedule
Active Ingredient/Active Moiety
Ingredient Name Basis of Strength Strength
isoproterenol hydrochloride (isoproterenol) isoproterenol 0.16 mg
phenylephrine bitartrate (phenylephrine) phenylephrine 0.24 mg
Inactive Ingredients
Ingredient Name Strength
cetylpyridinium chloride
sorbitan trioleate
# Item Code Package Description Multilevel Packaging
1 NDC:0089-0735-21 300 AEROSOL, METERED (300 SPRAY) in 1 INHALER None
2 NDC:0089-0735-11 300 AEROSOL, METERED (300 SPRAY) in 1 INHALER, REFILL None
Labeler — 3M Pharmaceuticals

Revised: 10/2006 3M Pharmaceuticals

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