Guaifenesin
- Class: Expectorant
- Used for: chest congestion
- Say it: gwye-FEN-eh-sin
- Forms: tablet, oral liquid
Remember the name – GUAI → goo
GUAIFENESIN thins the GOO, so each cough shifts more and hurts less.
It is an expectorant, not a suppressant — the opposite job. A cough bringing something up is doing useful work, so pairing it with a cough suppressant works against itself.
GUAIFENESIN thins the GOO, so each cough shifts more and hurts less.
It is an expectorant, not a suppressant — the opposite job. A cough bringing something up is doing useful work, so pairing it with a cough suppressant works against itself.
Mnemonic: Guaifenesin loosens; it does not suppress
An expectorant thins secretions so a productive cough clears them. An antitussive does the opposite and stops the cough. Giving both at once works against itself.
An expectorant thins secretions so a productive cough clears them. An antitussive does the opposite and stops the cough. Giving both at once works against itself.
Side effects
Common: nausea, vomiting, dizziness
Serious:
Typical dose
200–400 mg every 4 hours; maximum 2.4 g daily
With plenty of fluid — the water does much of the work.
Check yourself
Why is guaifenesin not combined with a cough suppressant for a productive cough?
- Loosening secretions is useful only if the patient can still cough them up
- The two drugs bind the same receptor
- Guaifenesin inactivates antitussives chemically
- It would cause dangerous sedation
Show answer
A. Loosening secretions is useful only if the patient can still cough them up
The two aims are opposed. Thinning mucus helps a productive cough clear the chest; suppressing that cough leaves the thinned secretions sitting there — which is why combination cough mixtures are so often illogical.
See it, don't memorize it
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