Incidence of Nausea with Co-Amoxiclav
Nausea occurs in approximately 10-13% of patients taking co-amoxiclav (amoxicillin/clavulanic acid), making it one of the most common gastrointestinal side effects of this antibiotic.
Documented Incidence Rates
The FDA drug label for amoxicillin indicates that nausea is among the most common adverse reactions (greater than 1%) observed in clinical trials 1. More specific data from clinical research provides clearer incidence rates:
- In acute exacerbations of chronic bronchitis, nausea occurred in 13% of patients receiving co-amoxiclav compared to 10.3% in the ciprofloxacin group 2
- In lower respiratory tract infections, gastrointestinal adverse events were common, though specific nausea rates were not isolated from other GI symptoms 3
- In purulent sinusitis, nausea was reported as one of the mild adverse events in 7.7% of co-amoxiclav-treated patients 4
Comparative Context
When compared to other antibiotics in head-to-head trials:
- Co-amoxiclav caused nausea in 10.6% of patients versus 13% with ciprofloxacin in one study 2
- Overall gastrointestinal side effects (including nausea) occurred in 25% of co-amoxiclav patients versus 12.4% with ciprofloxacin 5
- In pediatric otitis media, gastrointestinal effects were reported in 4% of co-amoxiclav patients versus 8% with azithromycin 6
Clinical Characteristics
Severity and management considerations:
- Most nausea associated with co-amoxiclav is mild to moderate in severity 2
- Gastrointestinal adverse events, including nausea, typically resolve spontaneously without requiring drug discontinuation 4
- In chronic rhinosinusitis studies, diarrhea was more commonly reported than nausea as the primary GI complaint 5
- Adverse events led to treatment discontinuation in approximately 7% of co-amoxiclav patients, with GI symptoms being the primary reason 5
Important Clinical Considerations
Taking co-amoxiclav with food may reduce the incidence and severity of nausea, though this specific recommendation is extrapolated from oseltamivir data where food intake reduced GI symptoms 5.
The overall adverse event profile shows that gastrointestinal symptoms dominate the side effect spectrum for co-amoxiclav, with nausea being consistently reported alongside diarrhea, abdominal pain, and flatulence across multiple clinical trials 5.