On Tue, 17 Mar 1998, Jay Pershad, M.D. wrote [snip]:
> I was intrigued at your choice of decongestants for these asthmatics
> with persistent cough despite use of beta agonists. In particular, I was
> wondering what your rationale for use of methscopalamine was, over and
> above an antihistaminic and decongestant. Moreover, what is the
> pediatric dosing? Is it available in a liquid preparation? What is your
> common choice amongst the commercial preparations? Would plain
> pseudoephedrine achieve the same purpose as all these "combos"?
I started using the methscopolamine combo when I was an allergy fellow and
found them to be much better at drying up AR then just plain pseudophed or
antihistamine-decongestant combo. In fact, my medicaid parents were so
pleased they would pay for these medicines (this product was not covered
by medicaid in the state where I did my allergy work).
All contain phenylephrine and chlorpheniramine, in additon to the
methscopolamine, and are by prescription only. There are several companies
who market this product. At least one company has a line which has a
syurp, chew tab and sustained release capsules. The syrup and chew tab
have 10mg phenyleprine, 2mg chlorpheniramine and 1.25mg methscopolamine
(per 5 mL and tab respectively). I base the dosing on the
chlorpheniramine: 0.35 mg/kg/day divided q 4-6 hr under 2, 1 mg q 4-6 hr
age 2-6, 2 mg q 4-6 hr over age 6. (Adult dose would be 10 mL or 2 chew
I do not use these products to treat colds/URI's, but allergic rhinitis
> One of my concerns, albeit unproven, is that since asthma has a
> predominant airway inflammatory component, the use of all these
> decongestants would "dry" out the lower airway secretions causing
> inspissation and worsening of the coughing spells, as the patient
> attempts to clear his or her airway.
The issue of "drying out" and inspissation of mucus in the lungs from
antihistamines or methscopolamine is an "old salt" tale, and is leftover
in the PDR from a very long time ago. No one that I am familiar with in
the allergy community considers this an issue, let alone a problem.
> I agree with your approach to treating undiagnosed or undertreated
> sinusitis. In fact, I would add that sinusitis is often a forgotten
> frequent trigger for asthma exacerbations too.
You will find a subset of children who either have frequent exacerbations
of their asthma, or recurrent sore throats. Both groups get better after
treatment, only to become ill again in a few days to weeks. These are the
patients who most likely have un- or under-treated sinusitis. They
benefit from a 4-6 weeks course of antibiotics and intranasal steroids.
> If the child can do PEFR, I try to sort out some of these residual
> coughs as being residual occult bronchospasm versus
> URI/sinusitis/allergic rhinitis. If their PEFR is suboptimal, I would be
> aggressive with bronchodilator therapy including ipatropium.
One word of caution: a "normal" peak flow in someone without a personal
best may not be normal. A number of children I have delt with in the past,
have had 100% pre-bronchodilator PEFR only to go "super-normal" after a
neb (e.g. >125% predicted).
> One other situation that I believe deserves mention, is persistent
> nocturnal cough in asthmatics that may benefit from the often forgotten
> SR Theophylline preparations.
I also agree with you that theophylline still has a place in the chronic
managment of asthma. But albuterol SR also works well in these kids with
less side effects and risk then theophylline.
Jay, thanks for the good questions and comments,
Jeff Linzer MD MICP
Division of Emergency Medicine
Egleston and Hughes Spalding Children's Hospitals
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