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What is isoproterenol inhalation?
Isoproterenol is a bronchodilator. It works by relaxing muscles in the airways to improve breathing. Isoproterenol inhalation is used to treat conditions such as asthma, bronchitis, and emphysema. Isoproterenol inhalation may also be used for conditions other than those listed in this medication guide.

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What are the possible side effects of isoproterenol inhalation?

If you experience any of the following serious side effects, stop using isoproterenol inhalation and seek emergency medical attention or contact your doctor immediately:

• an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, tongue, or face; or hives); or

• chest pain or an irregular heartbeat.

Other, less serious side effects may be more likely to occur. Continue to use isoproterenol inhalation and talk to your doctor if you experience

• headache, dizziness, lightheadedness, or insomnia;

• tremor or nervousness;

• sweating;

• nausea, vomiting, or diarrhea; or

• dry mouth.

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.

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How should I use isoproterenol inhalation?
Use isoproterenol inhalation exactly as directed by your doctor. If you do not understand these directions, ask your pharmacist, nurse, or doctor to explain them to you. To use the inhaler: Shake the inhaler several times and uncap the mouthpiece. Breathe out fully. Put the mouthpiece of the inhaler or spacer into your mouth. Be sure the mouthpiece is above the tongue and past the teeth. Alternatively, place the inhaler mouthpiece (not with spacer attached) several inches in front of your open mouth, if directed to do so by your doctor. Take a deep, slow breath as you push down on the canister. Hold your breath for 10 seconds, then exhale slowly.

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What is the most important information I should know about isoproterenol inhalation?
It is important to use the isoproterenol inhaler properly, so that the medicine gets into the lungs. Your doctor may want you to use a spacer with the inhaler. Talk to your doctor about proper inhaler use. Seek medical attention if you notice that you require more than your usual or more than the maximum amount of any asthma medication in a 24-hour period. An increased need for medication could be an early sign of a serious asthma attack.

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What happens if I miss a dose?
Use the missed dose as soon as you remember. However, if it is almost time for the next regularly scheduled dose, skip the missed dose and use the next one as directed. Do not use a double dose of this medication.

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What other drugs will affect isoproterenol?
Before using this medication, tell your doctor if you are taking any of the following medicines: a beta-blocker such as atenolol (Tenormin), metoprolol (Lopressor, Toprol XL), propranolol (Inderal), and others; a tricyclic antidepressant such as amitriptyline (Elavil), doxepin (Sinequan), imipramine (Tofranil), nortriptyline (Pamelor), and others; a monoamine oxidase inhibitor (MAOI) such as isocarboxazid (Marplan), phenelzine (Nardil), or tranylcypromine (Parnate); another inhaled bronchodilator; or

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Can I take this if I am pregnant or trying to get pregnant or if I am breastfeeding?

Isoproterenol has been assigned to pregnancy category C by the FDA. Animal studies have shown evidence of teratogenicity, but teratogenicity has not been reported in humans. There are no controlled data in human pregnancy. Isoproterenol is only recommended for use during pregnancy when there are no alternatives and benefit outweighs risk.

Isoproterenol crosses the human placenta. In vitro studies show that 2.8% to 27.3% of a labeled isoproterenol dose crosses the placental barrier within 10 minutes; of the amount that crosses, 92% to 96% was isoproterenol, the rest being metabolite. The Collaborative Perinatal Project reported 31 of 50,282 mother-child pairs reviewed were exposed to isoproterenol. Of the 31 pairs, two malformed children were born; the malformations were not described. The crude relative risk for malformations associated with isoproterenol was calculated to be 1.00, the hospital standardized relative risk, 0.94, and the survival and race standardized risk 1.02. In general, there was a trend for increased risk of minor, non-life-threatening malformations with some sympathomimetic agents, especially eye and ear malformations, but information specific to isoproterenol is unavailable. Isoproterenol is known to inhibit human uterine contractile intensity, but not necessarily contractile frequency, at concentrations less than 10 mcM/L. At concentrations greater than 10 mcM/L, limited in vitro data show that isoproterenol enhances uterine contraction force. Limited data from 5 pregnant women at term show that the dosage required to produce a 25% increase in mean maternal heart rate averages 3.6 mcg, which is significantly more than that required in nonpregnant women (0.7 mcg) or pregnant women at term with mild preeclampsia (0.8 mcg). The significant difference between preeclamptic and non-preeclamptic pregnant women complicates efforts to design a chronotropic epidural anesthesia test dose that is both safe and effective for all pregnant women. In these dose-finding studies, no fetal distress was associated with isoproterenol; one case of fetal heart rate deceleration two minutes after the mother received 0.25 mcg was associated with a Braxton-Hicks contraction.

There are no data on the excretion of isoproterenol into human milk. The manufacturer recommends that caution be used when administering isoproterenol to nursing women.

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Who should NOT use this medication?

• Angina pectoris.
• Preexisting cardiac arrhythmias (particularly ventricular arrhythmias requiring inotropic therapy and tachyarrhythmias) other than those arrhythmias that may respond to treatment with isoproterenol.
• Tachycardia or AV block caused by cardiac glycoside intoxication.

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What does my medication look like?
Isoproterenol inhalation is available with a prescription under the brand name Isuprel. Other brand or generic formulations may also be available. Ask your pharmacist any questions you have about this medication, especially if it is new to you. Isuprel Mistometer 11.2 grams Isuprel Mistometer 16.8 grams Isuprel Mistometer 16.8 grams

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What happens if I overdose?
Seek emergency medical attention if an overdose is suspected. Symptoms of an isoproterenol inhalation overdose may include angina or chest pain, irregular heartbeats or a fluttering heart, seizures, tremor, weakness, headache, nausea, and vomiting.

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What should I discuss with my healthcare provider before using isoproterenol inhalation?
Before using this medication, tell your doctor if you have heart disease or high blood pressure; epilepsy or a seizure disorder; diabetes; an overactive thyroid (hyperthyroidism); or liver or kidney disease. You may require a dosage adjustment or special monitoring during treatment if you have any of the conditions listed above. Isoproterenol inhalation is in the FDA pregnancy category C. This means that it is not known whether it will be harmful to an unborn baby. Do not use this medication without first talking to your doctor if you are pregnant or could become pregnant during treatment.

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Can I stop taking the medication if I feel better?
As a general rule, you should always take your medications exactly as prescribed and do not change the dosage or stop taking the medication without first discussing it with your healthcare provider.

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I am on so many medications; do I have to take them all?
This is called polypharmacy—many different medications being used at the same time by one person. Sometimes, being on multiple medications is acceptable and appropriate but at other times it may be problematic. If you are receiving your medications from multiple physicians you need to ensure that they all know what medications you are taking. The best way to do this is to make a list of all the medications you are currently using, including all nutritional supplements, homeopathic remedies, vitamins and over-the-counter drugs (if possible, also include all the diseases you have been diagnosed with). Give a copy to every doctor who takes care of you so they have it on file, this way they can avoid duplicating medications and perhaps even try to consolidate some. After every doctor's visit remember to update the list accordingly. Also, as much as you possibly can, try to use the same pharmacy to fill all your prescriptions, this way any potential drug interactions can be caught and averted.

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Where can I get more information?
More Information

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