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Different Types of Guaifenesin and its Recently Changed Status with the FDA
Single-ingredient guaifenesin refers to a product where
guaifenesin is the only active ingredient. This is the only guaifenesin
recommend for the nonplus conditions. Guaifenesin that is combined with
other ingredients whether in cough syrups or in pill form is not generally
considered appropriate for our purposes.
Guaifenesin comes in
two types, both of which are non-prescription, immediate-release, IR, and
extended-release, ER guaifenesin. Immediate-release guaifenesin is also
called QA, meaning quick acting and FA, fast acting. Immediate-release
guaifenesin is also available as a liquid and is found in most grocery and
drug stores. The liquid form frequently contains food coloring and
sweeteners and is not recommended due to these additives. Guaifenesin
contained in liquid cough and cold medications is not considered appropriate
for treating the nonplus conditions due to the other ingredients.
Extended-release guaifenesin is sometimes known by several other names:
long-acting, LA, sustained-release, SR, and bi-layered.
The two different types of guaifenesin currently sold
both work well when used for treating the nonplus conditions. However, if a
person changes the type of guaifenesin they are using (from immediate
release to extended release or vice versa) an adjustment in dose may be
necessary to achieve the same level of symptomatic change. It is not unusual
to require a slightly lower daily dose if one is using immediate-release
when compared to extended-release. This means that if a
person switches from extended-release to immediate-release the dose may need
to be lowered. Conversely, an increased dose may be necessary if switching
from immediate-release to extended-release. The difference in dose between
the two often ranges from 20 % to 70%. However, a change in dose is not
always required. If you change from one type to another, pay attention to
your symptom changes and be prepared to alter your dose to achieve the ideal
amount of symptomatic change as discussed in The Guaifenesin Guide,
Chapter 8, Finding Your Dose.
Because of problems with the release rate of many
brands of extended-release guaifenesin, the FDA has stopped all companies
except one from selling extended-release guaifenesin. As of December 2003
the only single-ingredient extended-release guaifenesin available is a
bi-layered guaifenesin that contains some immediate release guaifenesin
also. This product is labeled as an
extended-release guaifenesin and the above suggestions for extended-release
still apply.
Even though all brands of guaifenesin currently
available work consistently well, whether extended-release or
immediate-release, you should be aware that many brands of extended-release
guaifenesin sold prior to December of 2003 may not be effective. (1) This unfortunate problem has no doubt resulted in many
people and physicians failing to get results when using it as a treatment
for the nonplus conditions. If you were one of the people who used ER, SR
or LA guaifenesin before December of 2003 and did not get the results you
expected, I encourage you to give guaifenesin another try.
All legally manufactured single-ingredient guaifenesin
now sold, whether immediate-release or extended-release is FDA approved. No
approval has a higher status than another with regards to guaifenesin.(2)
- U. S. Food and Drug Administration News,
10-17-2003, ‘FDA Proposes Steps to Assure the Safety and Efficacy of
Certain Currently Unapproved Medicines.’
www.fda.gov/bbs/topics/NEWS/2003/NEW00962.html Accessed 2004 July
20.
- Food and Drug Administration Center for Drug
Evaluation and Research, Letter to Author, 8-27-04.
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