guaifenesin
Brand names: Mucinex
Guaifenesin (Mucinex) is a medicine that helps to loosen mucus in your lungs. It makes it easier to cough up.
Drug Pricing (NADAC)
Generic Price
$0.01/unit
Generic Available
Yes (17 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
This medicine helps with coughs caused by minor throat and lung irritation.
Common side effects
Nausea, Vomiting, Headache
Key warnings
Do not give to children under 4 years of age.
How It Works
Guaifenesin is an expectorant. It works by thinning the mucus in your airways. This makes the mucus easier to cough up and clear from your lungs.
How to Take It
Take this medicine every 4 hours as needed. Do not take more than 6 doses in 24 hours. Shake the bottle well before each use. Use the provided dosing cup to measure the correct amount.
Pregnancy & Breastfeeding
Talk to your doctor before taking this medicine if you are pregnant or breastfeeding. It is important to weigh the potential benefits against any risks to your baby.
Missed Dose
If you miss a dose, take it as soon as you remember. Do not take more than 6 doses in 24 hours.
Storage
Store at room temperature, away from heat and moisture.
Side Effects (from patient reports)
Based on 17,156 FDA adverse event reports.
FDA Adverse Event Report Analysis
Detailed analysis of 29,404 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 1998–2025.
Total Reports
29,404
Death-Related Reports
2,163
Hospitalization Reports
7,581
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | DRUG INEFFECTIVE | 2,450 |
| 2 | DYSPNOEA | 2,178 |
| 3 | FATIGUE | 1,782 |
| 4 | NAUSEA | 1,743 |
| 5 | DIARRHOEA | 1,645 |
| 6 | PNEUMONIA | 1,641 |
| 7 | COUGH | 1,557 |
| 8 | HEADACHE | 1,506 |
| 9 | DIZZINESS | 1,400 |
| 10 | PAIN | 1,251 |
| 11 | OFF LABEL USE | 980 |
| 12 | VOMITING | 945 |
| 13 | ASTHENIA | 928 |
| 14 | DEATH | 917 |
| 15 | FALL | 887 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Do not give to children under 4 years of age.
Common Questions
What is guaifenesin used for?
How often can I take this medicine?
Can I give this to my child?
What should I do if I miss a dose?
Are there any side effects?
Can I take this while pregnant?
How should I store this medicine?
Can I take this with other medicines?
What if it doesn't seem to be working?
Do I need a prescription for this medicine?
What are the common side effects of guaifenesin?
What drug class is guaifenesin?
Is guaifenesin safe during pregnancy?
Has guaifenesin been recalled?
Active Recalls
CGMP Deviations: Firm went out of business and could no longer continue stability studies.
Akorn, Inc.
Related Medications in Expectorant
Other drugs grouped near guaifenesin — same-class peers and common alternatives.
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Fasenra
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What the FDA Data Shows for guaifenesin
The FDA label for guaifenesin (sold under brand names such as Mucinex) classifies it as an over-the-counter product in the Expectorant class. This medicine helps with coughs caused by minor throat and lung irritation. Official labeling lists 4 commonly reported side effects, including Nausea, Vomiting, Headache.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 17,156 voluntary reports. Interaction data is drawn directly from FDA-approved prescribing information. NADAC pricing from CMS shows a generic unit cost of $0.01.
Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history (currently 1 recall record on file), and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: October 14, 2025
Read our methodology — how this data is sourced, computed, and verified.
All federal data sources used on this page
- FDA Orange Book — approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed — NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) — post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm — standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files — federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database — current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages