DRUG INDEX
Asthma: Over The Counter Treatment
Asthma is a disease in which there is a brief, temporary (transient) narrowing of the airways in the lung (bronchospasm). This contraction prevents air from moving in and out of the lungs easily. As a result, an asthmatic patient has episodes in which breathing is difficult. An asthmatic episode can resolve spontaneously or may require treatment.
Asthmatic patients and their physicians may select from a wide variety of prescription medications. This is not true for over-the-counter (OTC) medicines, which are limited to epinephrine (adrenaline) and ephedrine. In addition, many asthmatic patients should not use epinephrine or ephedrine because of their relatively weak effectiveness or side effects.
To decide whether an OTC epinephrine or ephedrine product may be useful, viewers should understand: (1) the abnormal conditions that exist in the airways of asthmatics; (2) the effects of epinephrine and ephedrine; (3) the specific factors that should be considered when choosing and using epinephrine and ephedrine; and (4) the side effects of these drugs.
What is asthma?
The cause of asthma is unknown. More is known about the abnormal conditions that occur in asthma. These conditions include: (1) hyper-responsiveness (contraction) of the muscles of the breathing airways in response to many stimuli such as exercise or allergies (e.g., drugs, food additives, dust mites, animal fur, and mold); (2) inflammation of the airways; (3) shedding of the tissue lining the airways: (4) increased secretion of mucus in the airways: and (5) swelling of the walls of the airways with fluid. All of these conditions narrow the airways and make breathing difficult. Symptoms of asthma include wheezing (the hallmark of asthma), coughing, difficulty breathing, and tightness of the chest. Asthma is diagnosed by the presence of wheezing, but can be confirmed by tests (spirometry) that evaluate the movement of air into and out of the lungs.
What medications are used to treat asthma?
Epinephrine and ephedrine once were the only effective medications for treating asthma. Beginning in the 1980's, newer medications were introduced that target more of the abnormal conditions in asthma and do so more effectively than epinephrine or ephedrine. For example, prescription inhaler forms of beta2 -agonists, albuterol , and metaproterenol (Proventil and Alupent); corticosteroids, beclomethasone and flunisolide (Beclovent and Aerobid); and anticholinergics, ipratropium bromide (Atrovent), and others medicines are now widely used because of their greater effectiveness and fewer side effects.
How do OTC medicines for asthma work?
Epinephrine acts by relaxing the muscles of the airways, thereby opening up the airways and allowing air to flow in and out of the lungs more easily. Ephedrine also relaxes the muscles of the airways.
What factors should be considered in choosing and using OTC epinephrine or ephedrine?
Despite the development of newer medications, epinephrine and ephedrine remain available as OTC medications. The choice of epinephrine or ephedrine should involve consideration of several factors. Most importantly, the asthma should be mild and less frequent, defined as occurring less than once per week and lasting from a few hours to a few days at most. OTC epinephrine or ephedrine is best used under the guidance of a physician. A patient should seek medical attention and prepare to switch to a prescription asthma medication if: (1) moderate to severe asthma develops; (2) frequent or regular doses of epinephrine or ephedrine are needed to relieve symptoms: (3) episodes of asthma occur once or more per week; or (4) asthmatic episodes develop at night.
OTC epinephrine is available in various concentrations for oral inhalation or as a solution in vaporized form (nebulization). Both forms may or may not contain alcohol or sulfite as preservatives. For example, Asthmahaler Mist does not contain alcohol. Alcohol and sulfite preservatives may trigger an attack of asthma, and, therefore, patients whose asthma is sensitive to these preservatives should read product labels carefully. The nebulized epinephrine solutions may or may not require diluting with a separate saline (salt) solution before use. Several saline solutions are available OTC in various concentrations. Again, careful reading of the label will provide information about combining an epinephrine solution for nebulization with a specific saline solution. Oral epinephrine is unavailable because it is rapidly broken-down in the digestive system before it can reach the lungs. Once inhaled, epinephrine should provide rapid relief of symptoms (within 5-10 minutes) and continue working for 1-3 hours. Good inhaler and nebulizing techniques are critical in the use of epinephrine. If epinephrine is used frequently, tolerance to its effects occurs, that is, repeated inhalations provide progressively less and less benefit.
OTC ephedrine is available only as an oral medication in combination with guaifenesin as caplets, tablets, or syrup. (Guaifenesin is an expectorant that loosens mucus in the airways and facilitates its removal by coughing.) Caution should be used when first starting these products since they occasionally irritate the airways of some patients and may make the asthma worse. OTC ephedrine should provide relief of symptoms within 15-60 minutes and may continue to be effective for 3-5 hours. Continued use of ephedrine, like frequent use of epinephrine, leads to tolerance.
Neither epinephrine or ephedrine should be continued if thick mucus or sputum (colored mucus) develops and/or a persistent or chronic cough occurs with the asthma. These may be signs of infection in the lungs and require immediate medical attention. If OTC asthma drugs do not relieve an episode of asthma within 10 (for epinephrine) or 60 minutes (for ephedrine) or the symptoms worsen, medical attention should be sought immediately.
What side effects and drug interactions are there with OTC asthma medicines?
Ephedrine poses a greater chance of causing adverse drug effects or drug interactions than epinephrine because it must be absorbed into the body to be effective. Nervousness, sleeplessness, anxiety, nausea, reduced appetite, rapid heart beat, tremors (the "shakes"), and urinary retention are the most common adverse effects. Immediate medical attention may be necessary for these side effects.
Monoamine oxidase inhibitors (phenelzine, isocarboxazid), clonidine , selegiline, guanethidine, and ergotamines (ergotamine tartrate, dihydroergotamine mesylate) may increase blood pressure when used at the same time as ephedrine. Methyldopa or reserpine may reduce ephedrine levels in the blood and thereby lessen the effectiveness of ephedrine. Tricyclic anti-depressants ( desipramine , amitriptyline , doxepin , and imipramine ) may block the effect of ephedrine. The carbonic anydrase inhibitors acetazolamide and dichlorphenamide may raise ephedrine blood levels and increase the risk of side effects from ephedrine. Patients taking any medications should consult with their physician or pharmacist before starting OTC ephedrine.
Since epinephrine is inhaled directly into the lungs and little is absorbed into other organs of the body, there is less risk for side effects. Epinephrine rarely causes rapid heartbeat, irregular heart rhythms, high blood pressure , tremor , or anxiety.
Since there are specific risks with epinephrine or ephedrine in certain medical conditions, physician advice and supervision should be sought before taking epinephrine or ephedrine if there is heart disease (coronary artery disease, congestive heart failure , irregular heart rhythms), high blood pressure, thyroid disease, diabetes, or difficulty urinating due to enlargement of the prostate. In addition, patients should seek medical advice before taking ephedrine if they already are taking anti- depressants.
What are additional measures in the management of asthma?
- Patients should avoid known triggers of asthma attacks (e.g., exercise or allergens).
- Good control of allergic rhinitis (nasal allergies) helps to control asthma.
- Two to 10% of patients with asthma must avoid aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs, e.g. ibuprofen or Motrin) since they may induce an episode of asthma.
- All asthma patients should avoid beta-blocker drugs (Inderal, Tenormin, Visken, and Lopressor) because they may worsen asthma or precipitate an episode.
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