EPITOMES-ALLERGY

Newer Antiasthmatic Agents THE OUTLOOK for the pharmacotherapy of asthma has been brightened in the past several years by advances in our understanding of the pharmacokinetics of theophylline. These have led to increased benefit from this medication in the introduction of alternate-day therapy with short-acting corticosteroids to minimize side effects of these drugs, and the addition of sodium cromolyn by inhalation, to our armamentarium. The catecholamines act directly on the beta adrenergic receptor which activates adenyl cyclase resulting in increased synthesis of cyclic adenosine monophosphate (CAMP), while theophylline inhibits phosphodiesterase thus decreasing the degradation of intracellular CAMP. These agents act synergistically to increase CAMP levels. Drugs which increase intracellular CAMP cause bronchial relaxation as well as decrease release of mediators of immediate hypersensitivity, histamine and slow reacting substance of anaphylaxis (SRS-A). New catecholamine bronchodilators have been introduced which stimulate the /8-2 receptors in the lung to a greater degree than the /3-1 receptors of the cardiovascular system. The three new compounds which have been studied most extensively are metaproterenol (Alupent® or Metapryn®), terbutaline and salbutamol. Metaproterenol is available in the United States in inhalable and oral forms and appears to be effective but not completely free of cardiovascular and agitation side effects. Terbutaline is currently available in the United States only in an injectable form (Bricanyl®) which offers little advantage to epinephrine except a slightly longer duration of action. Salbutamol (Albuterol®) is not yet available in this country but has been used widely in Europe and Latin America. Its advantages appear to be its long duration of action and potent /-2 effects with a minimum of side effects. Further clinical studies comparing these newer bronchodilators are under way to define their relative usefulness. Another potential approach to pharmacotherapy in asthma is the use of a-adrenergic blockade. Few clinical data are available to date. In addition, the use of the cholinergic inhibitor atropine has also been reexplored since the increased emphasis on the importance of cholinergic stimuli in mediating bronchoconstriction. The prostaglandins El and E, are potent bronchodilators and may be useful in the future. Finally, a sodium cromolyn derivative in an oral form (AH 7725) and beclo-

methasone, a steroid administered topically in low doses by inhalation without evidence of suppression of the hypothalamic-pituitary-adrenal axis, show therapeutic promise. HARVEY D. GORRIN, MD ROBERT N. HAMBURGER, MD REFERENCES

Cloninger P, Wilson AF, Novey HS: Six-month evaluation of a new long-acting bronchodilator, terbutaline. J Allergy Clin Immunol 53:84, Feb 1974 Siegel SC, Bernstein IL, Katz R, et al: Double-blind controlled evaluation of oral salbutamol (Albuterol®). J Allergy Clin Immunol 53:83, Feb 1974 Weinberger MM, Bronsky EA: Evaluation of oral bronchodilator therapy in asthmatic children. J Pediatr 84:421, Mar 1974 Assem ESK, Evans JA, McAllen M: Inhibition of experimental asthma in man by a new drug (AH 7725) active when given by mouth. Br Med J 1:93, Apr 1974

Current Status of Bronchial Inhalation Challenge in Asthmatics THE RATIONALE for the direct inhalation of suspected allergen extracts by extrinsic asthmatics is the possibility that immunoglobulin E (IgE) antibodies with specificity for the causative allergens may be present in the bronchial mucosa and better reflect the reactivity of the airway in asthma than skin fixed or serum IgE antibodies. The procedure employing inhalant allergen extracts is being used by many research laboratories in the hope that it will prove to be a more direct, accurate and relevant method to show the causative role of specific aeroallergens in asthma when there is a discrepancy between the clinical history and the skin tests. The inhalation test may also result in a more judicious selection of clinically relevant allergens in immunotherapy (hyposensitization), especially in asthmatic patients with multiple positive skin reactions and perennial asthma. It could also be used as a method to evaluate the effects of immunotherapy in asthma, as one study has shown that such therapy could result in changes in bronchial reactivity with or without concomitant clinical improvement of the disease. Late reactions consisting of bronchospasm and a drop in pulmonary function about 4 to 6 hours following inhalation of allergens have been reported in some patients and make it imperative that such procedure be carried out with proper medical supervision, including provision for immediate admission to hospital. ZACK H. HADDAD, MD REFERENCES Spector SL, Farr RS: Bronchial inhalation procedures in asth-

matics. Med Clin North Am 58:81, Jan 1974 Tuchinda M, Chai H: Effect of immunotherapy in chronic asthmatic children. J Allergy Clin Immunol 51:131, Mar 1973

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Current status of bronchial inhalation challenge in asthmatics.

EPITOMES-ALLERGY Newer Antiasthmatic Agents THE OUTLOOK for the pharmacotherapy of asthma has been brightened in the past several years by advances i...
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