Drugs in Allergic Disorders: Expectorant Drugs. Atropine
Expectorant Drugs
Expectorant drugs such as iodides may be helpful in ten percent of perennial asthmatics. A dose of potassium iodide at 15 mg/kg/day in divided doses is effective. Response occurs within the first 14 days. If there is no adequate response during this time, there is no point in persisting with this drug.
The mechanism of iodides’ action on asthma is largely unknown. The side effects to be looked for are acne in the post pubertal age group, rhinorrhea, a metallic taste in the mouth, and a rash. Enlargement of the thyroid without abnormalities of thyroid function may also be noticed. Iodides must not be given to pregnant women, since there is a danger of goitre in the newborn.
Atropine (Anticholinergic Drugs)
Asthma is considered a disorder of possible autonomic imbalance with par a sympathetic (cholinergic) predominance; the characteristic hyperirritability of the airways may be attributed to this. Stimulation of the tracheobronchial tree by dust, sulfur dioxide, cold air, or antigen in sensitized subjects initiates a vagal reflex which induces bronchoconstriction. It may be that some patients will respond well to anticholinergic drugs, and there is renewed interest in clinical research. In the future, we may see atropine-like drugs being used clinically; currently, there are none available for use in clinical practice.
In all allergic patients, nose drops are contraindicated. However, nasal decongestants such as pseudoephedrin syrup or tablets orally may be useful. Tranquillizers should be avoided as much as possible. However, I have found hydroxyzine (Atarax) useful in starting doses of five mg every four hours for children six years or younger, ten mg every four hours for older children, and 25 mg three times a day for adults.
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