Asthma Medicines

Theophylline has been used for treating bronchial asthma for nearly sixty years but is a weaker bronchodilator than the B-adrenergic agonists. Although widely used as a bronchodilator, the mechanism of its action is unclear. The most recent theories suggest an anti-inflammatory effect that is supported by the inhibition of the late phase response. Due to the controversy over its mode of action, theophylline has fallen out of favor and is no longer regarded as a first-line asthma medication comparable to the B2adrenergic agonists. As more data is obtained that firmly establishes theophylline as an anti-inflammatory agent it is likely to be regarded again as a first-line agent.

At this time theophylline may still prove useful as a second-line drug. A recent study has demonstrated that theophylline may allow patients who require high doses of inhaled corticosteroids to reduce their steroid dosages. Patients with intolerance to B-agonist side effects may find they are better able to tolerate theophylline. Its availability as an oral medication in a sustained time release form may be preferred by some patients. Dosing is usually on a twice-a-day basis, with some patients able to achieve satisfactory results from once-a-day administration. This once-a-day dose is best given in the evening and may prove extremely helpful in treating nocturnal asthma.

Sustained-Release Preparations

Large numbers of sustained-release theophylline preparations are available by prescription, but they may vary in their rate of release of medication into the bloodstream. Once a certain preparation is prescribed, adjustment of the dosage will require follow-up and blood testing. After the proper dosage is established it is advisable not to substitute one preparation for another since the substitute may not achieve the same results. There is little use for short-acting theophylline preparations since they must be given several times a day.

Intravenous Form: Aminophylline

An intravenous form of theophylline known as aminophylline is available for emergencies. In view of the faster onset of action of the B2-adrenergic agonists intravenous aminophylline would also not be considered a first-line treatment in an emergency room. Although there is some controversy concerning its effectiveness in emergencies, aminophylline’s use as a second-line agent has been established.

Obtaining a Therapeutic level

One drawback to theophylline is that a certain amount must be present to achieve an effect. This has been termed a therapeutic level (10-20 mg of the drug per liter of blood). Some patients, however, may benefit from lower levels. To achieve the therapeutic level a certain dosage must be administered. Dosing is based on the patient’s body weight and when given by mouth may require several adjustments based on blood test results before the achievement of a patient’s daily maintenance dose. When theophylline is given by mouth an effect may be achieved in approximately one hour but it may require two to three days to achieve the desired maintenance level. With intravenous administration of aminophylline a “loading dose” is usually given over thirty minutes, followed by a constant infusion. Blood levels are again required to adjust the intravenous drip. Compared to the rapidly acting B-agonists, theophylline is both weaker and slower in producing bronchodilatation. Of note, however, when theophylline is given at the same time that the patient is receiving the B-agonist, the effect of the two drugs together may be greater than when given alone.

Adverse Effects of Theophylline

Besides the above considerations, theophylline may have significant side effects, often related to high blood levels, but some patients may experience adverse effects from small dosages, including stomach and bowel upset, rapid or irregular heart beat, insomnia, nervousness, urinary frequency, and headache. Some of these effects may be prevented or reduced by avoiding caffeine, which is structurally similar to theophylline; this explains why coffee has often been noted to relieve asthma. Patients should be advised to avoid or reduce caffeine in their diets while receiving theophylline.

Children and Theophylline

One disturbing but controversial side effect has been noted in children. A possible adverse effect on learning and behavior has been raised by some studies. There are conflicting results with additional studies that have not demonstrated these effects. At this time, theophylline should be used with caution in young children. Careful monitoring for changes in behavior patterns and learning must be performed.

Overdosage

In excessive or toxic dosages, theophylline may cause nausea, vomiting, irregular heart rhythms, and seizures. Theophylline should never be used without direction and supervision from the physician. Fatalities have been reported in asthmatics who have overused over-the-counter asthma medications that contain theophylline. These arc preparations should be withdrawn to avoid toxic reactions.

Drugs That Interact with Theophylline

Another important consideration when patients receive theophylline is the potential for drug interaction. This interaction may result in higher blood levels or toxicity from theophylline. One major group of drugs that can interact with theophylline are certain antibiotics, including erythromycin, clarithromycin, ciprofloxacin, levafloxacin, and olfloxacin. In addition, a widely prescribed stomach medication, cimetadine (Tagamet), may also interact with theophylline. One of the anti-leukotrienes, zileuton (Zyflo) has also been found to interact with theophylline. Fortunately, many other antibiotics and stomach medications, and anti-leukotrienes, are compatible with theophylline. In instances where one of the drugs that may interact with theophylline must be given, a reduction in the theophylline dosage may be made in order to avoid toxicity. A simple rule is to cut in half the total daily dose whenever receiving one of the above medications. It is vital to monitor blood levels in that situation.

Factors That Affect Theophylline Breakdown

Other factors may contribute to slower breakdown or clearance of theophylline, such as age, liver disease, and heart disease. Elderly patients have been found to clear theophylline more slowly. Patients with diseases of the liver as well as those with congestive heart failure have also been found to have slower metabolism of theophylline. In these groups, lower dosages of theophylline should be given.

Some drugs may accelerate clearance of theophylline from the body. Cigarette and marijuana smokers are often found to clear theophylline more rapidly than nonsmokers and may need their dosages increased. TWo medications used for epilepsy, phenytoin (Dilantin) and phenobarbital, may also increase breakdown of theophylline.

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Gold Salts

Gold salts have been adminitered to asthmatic patients based on the benefit of this drug in patients with rheumatoid arthritis. Small numbers of patients have been treated with gold injections or an oral gold compound called auranofin, and individual patients have been reported to reduce their symptoms and steroid requirements. Studies of large numbers of patients are lacking and this approach is not without adverse effects, since gold may also cause pulmonary fibrosis. For these reasons, the use of gold salts in the treatment of asthma must be regarded as investigational.

Troleandomycin

Troleandomycin (TAO) , an antibiotic, has been administered to asthmatic patients who have been steroid dependent. It appears to simply slow the excretion of one of the oral corticosteroids, methylprednisolone. Selected patients receiving methylprednisolone who are given troleandomycin have been able to reduce their steroid dosage. A similar effect of TAO has been noted on theophylline breakdown. For this reason, blood levels of theophylline are required of patients maintained on this medication during TAO administration. TAO has no anti-inflammatory effect of its own and may cause liver damage. It must be concluded that TAO has little place in the routine treatment of bronchial asthma.

Antihistamines

Antihistamines have long been regarded as contraindicated in asthmatics. This prohibition has stemmed from the drying effect antihistamines have on lung secretions and the greater potential for “plugging”of the bronchial tubes in asthmatic attacks. This adverse effect has clearly been documented in many patients. On the other hand, studies of large dosages of antihistamines in asthmatic patients have occasionally demonstrated a beneficial effect. This is not surprising, since histamine is one of the irritating substances involved in provoking an asthmatic attack.

Azelastine

Azelastine is an antihistamine that has undergone trials in Japan and other countries in patients with bronchial asthma. Despite early positive results no significant benefit has been proven in large numbers of patients. One adverse effect is drowsiness. This drug is not available in the United States.

Ketotifen

Another antihistamine, Ketotifen, has been available for use in Europe for bronchial asthma. Tb date, studies do not demonstrate a significant beneficial effect. This agent may also cause drowsiness. Until further studies of additional agents are made available there can be no basis for the routine use of antihistamines for treatment of bronchial asthma. Antihistamines may be carefully administered for nasal or sinus disease if the patient is closely monitored by a physician.

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These days many new effective treatments are available in the world’s global market which cures asthma completely and involves a simpler process. Medical science and Pharmacology have played a vital and promising role in controlling this problem.

Asthma treatment with ephedrine have made possible to treat asthma more effectively and efficiently. This treatment involves extraction of gland derived from xanthenes and theophylline which are extensively used in treatment of asthma. This is proved to be the most effective, ever lasting and sate technique to cure asthma.

Out of some commonly known methods bronchodilator is also very good solution to asthma. Effective bronchodilator is available now days which rapidly controls this problem. This drug is the most vital and important to control the increasing mortality rate. This drug is also good because it does not create any harmful effect on to the human body and the patient can live a normal life there after.

The main point here is that the patient should use these methods of controlling asthma after consulting to their doctors. Moreover the patient should not only use medicines only but should take adequate rest and control themselves from not to inhale pollutants and wind in to their bodies.

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Many patients fear they will become addicted to their asthma medications and be unable to stop their use. This may partly be due to dependence on medication for the relief of symptoms and attacks. This fear of addiction may explain why some patients do not take their medications.

There is no evidence of the development of addiction to asthma medications. When good control of asthma is achieved, it is often possible to reduce or discontinue medication that is no longer needed. However, good control must come first since withdrawal of medication may result in increased frequency of attacks.

Adrenal Insufficiency

In the case of systemic corticosteroids, the management of reduction and withdrawal of these agents must be closely supervised in view of possible adrenal insufficiency. Patients with severe asthma may become “steroid dependent” for control of their disease, but that does not represent an addiction to medication.

Are There Delay Effects of Asthma Medications?

Patients may be concerned whether long-term use of asthma drugs will have serious adverse effects, another reason why patients may reduce or eliminate medications on their own.

Long-term use in adults of the B-agonists, theophylline, cromolyn sodium, and inhaled corticosteroids have not shown any evidence of delayed adverse effects. In children, inhaled corticosteroids may have adverse effects on growth and bone development. These agents may still be necessary, however, when the risk of severe, uncontrolled asthma out-weighs the possible detrimental effects on bone growth. Nedocromil and ipratropium bromide are still relatively new and long-term experience with these agents is forthcoming. At this time there is no evidence of possible delayed adverse effects of these agents.

Oral Corticosteroids

In both children and adults, long-term effects of the oral corticosteroids must be anticipated. These effects are outlined above and must be weighed against the dangers of uncontrolled asthma. Once systemic steroids are required there should be frequent review of their necessity with the goal of reducing dosage or withdrawal if possible. Alternate-day administration should always be considered if patients must remain on oral corticosteroids.

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