Interesting article on the subject:

http://www.medscape.com/viewarticle/448588

Although the article is about COPD (chronic bronchitis), I think it would
probably also apply to chronic sinusitis. (The article refers to mucus
build-up in the lungs, but I assume the same results would apply to such
phlegm in the nose, throat, and sinuses.)

Interesting that it finds NAC (oral) to be more effective than guaifenesin.
One wonders then, why only the latter and not the former (frequently used in
much of the world for that purpose) are prescribed for that purpose in the
USA. NAC is available in the USA as a "supplement", but I don't know if that
is the same kind of dosage used as a mucolytic, and I've never heard a
doctor recommend its usage.

The results don't show very good results for NAC either, but a little better
than guaifenesin, which is the only medication prescribed (now only OTC) for
mucus-thinning in the USA.

I'm not sure what the author is referring to by "aerosolized surfactant",
which he indicates has also shown some positive results in this area.

For those of us with overly thick copious phlegm clogging our pipes, it sure
would be nice if a medication came out that really worked well for thinning
and loosening it (without negative side effects, of course! ;-) ) !

For those who'd rather not bother with going to Medscape, I'll repost the
text of the article here:

------article from Medscape, link above------

Use of Expectorants

Question

Is there evidence that expectorants are effective for any condition other
than cystic fibrosis? In my 25 years of experience in Canada, these were
hardly ever used for the treatment of chronic obstructive pulmonary disease
(COPD) -- bronchodilators were always the mainstay. What is the current
evidence related to the use of expectorants?

Harvey Solomon, MD

Response from David M. Quillen, MD
Assistant Professor, Department of Community Health and Family Medicine,
University of Florida, Gainesville.

COPD is a major cause of chronic morbidity and mortality throughout the
world and is currently the fourth leading cause of death worldwide, with
expected increases in the prevalence and mortality over the next few
decades.[1] Medications for COPD have not significantly changed over the
past few years. However, the mortality rate from COPD has increased with the
aging of the smoking population. It is not surprising that patients and
physicians try medications that might be beneficial even though the evidence
to support their use is not present.

The first thing we must be clear about is the difference between
expectorants and mucolytics. Many pharmaceutical agents that we think of as
expectorants are mucolytics and vice versa. An expectorant medication is one
that increases the output of thin respiratory tract fluid by helping to
liquefy the tenacious mucus that patients with COPD suffer from. A mucolytic
medication breaks down the mucus that is present in the lungs, which ends up
thinning the respiratory secretions. Medications that are classified as
expectorants are guaifenesin and iodinated glycerol. The mucolytics include
n-acetylcysteine and dornase alfa (recombinant human deoxyribonuclease I -
rhDNase). Despite the differences between mucolytics and expectorants, in
the end, the purpose of these medications is to thin lung secretions, making
them easier to clear by coughing and ciliary action.

Unfortunately, the expectorants have been disappointing in treating COPD.
Guaifenesin has been in use for a long time. Yet, there are no significant
studies supporting guaifenesin's benefit in COPD patients.[2] Iodinated
glycerol has also been used as an expectorant; however, there is a good
randomized clinical trial in which it failed to show efficacy in COPD
patients.[3]

The mucolytics show more promise than the expectorants. Aerosolized
surfactant, although not classified as a mucolytic, has been shown to have a
positive effect on patients with stable chronic bronchitis (a subcategory
and consistent with the diagnosis of COPD).[4] However, expense is certainly
an issue, and the author's admittedly small numbers would require larger
studies to confirm their findings.

Dornase alfa is an enzyme that selectively cleaves DNA. Purulent pulmonary
secretions in cystic fibrosis patients contain very high concentrations of
extracellular DNA. Dornase alfa has been shown to be effective and is FDA
approved for use in cystic fibrosis. Unfortunately, dornase alfa has not
been shown to be effective in COPD patients.[5]

Finally, there is n-acetylcysteine. Oral but not inhaled n-acetylcysteine
has been shown to have some efficacy in COPD patients. Systematic reviews of
the current trials confirm the efficacy of n-acetylcysteine and some other
mucolytics but question using them, given the modest results and high
cost.[6]

In summary, the mucolytics and expectorants, as a group, are disappointing
and, for the most part, lack efficacy. Only further clinical trials will
demonstrate more conclusively whether n-acetylcysteine really does benefit
patients. Physicians who treat patients with COPD need to review and follow
the World Health Organization Global Initiative for Chronic Obstructive Lung
Disease guidelines.[1] They represent the best practical, evidence-based
summary of current COPD care.

Posted 02/03/2003

----------------------------------------------------------------------------
----

References
 1.. Pauwels RA, Buist AS, Calverley PMA, Jenkins CR, Hurd SS. Global
strategy for the diagnosis, management, and prevention of chronic
obstructive pulmonary disease: National Heart, Lung, and Blood Institute and
World Health Organization Global Initiative for Chronic Obstructive Lung
Disease (GOLD): executive summary. Respir Care. 2001;46:798-825. Abstract
 2.. Ferguson GT. Update on pharmacologic therapy for chronic obstructive
pulmonary disease. Clin Chest Med. 2000;21:723-738. Abstract
 3.. Rubin BK, Ramirez O, Ohar JA. Iodinated glycerol has no effect on
pulmonary function, symptom score, or sputum properties in patients with
stable chronic bronchitis. Chest. 1996;109:348-352. Abstract
 4.. Anzueto A, Jubran A, Ohar JA, et al. Effects of aerosolized surfactant
in patients with stable chronic bronchitis: a prospective randomized
controlled trial. JAMA. 1997;278:1426-1431. Abstract
 5.. Fiel SB. Chronic obstructive pulmonary disease. Mortality and
mortality reduction. Drugs. 1996;52(suppl 2):55-60. Abstract
 6.. Poole PJ, Black PN. Oral mucolytic drugs for exacerbations of chronic
obstructive pulmonary disease: systematic review. BMJ. 2001;322:1271-1274.
Abstract