A Pill That Does a Lot of Work
Metronidazole is one of the world's most widely used antibiotics. It's the go-to treatment for a range of gut infections, certain sexually transmitted infections, and some skin conditions. In many countries, it's cheap, effective, and available without a prescription.
In sub-Saharan Africa, it is a workhorse of primary care. But workhorse drugs can sometimes be overworked.
When any antibiotic is used too often — or used in cases where it isn't needed — bacteria have more chances to develop resistance. Resistance means the drug stops working. An antibiotic that once cured a gut infection in three days may become ineffective, leaving patients sicker for longer with fewer alternatives.
This is the global antibiotic resistance crisis, and it affects every country. But the problem is most acute in low- and middle-income countries, where antibiotics are sometimes prescribed without lab tests to confirm what's actually causing the illness.
What Researchers Looked At
Scientists reviewed medical records from 11 primary care clinics in Abomey-Calavi, a city in South Benin, covering the year 2020. Five clinics were public facilities; six were private. They randomly selected 200 patient visits per clinic — 2,200 visits in total.
The typical patient was 19 years old, and just over half were female. Antimalarials (drugs to treat malaria) were prescribed in more than half of all visits, which reflects the high burden of malaria in the region.
The Numbers That Stand Out
Among all antibiotics prescribed, metronidazole was the second most common — appearing in 18 percent of visits. Only one class of drug, aminopenicillins (a broad group that includes amoxicillin), was prescribed more often at 27 percent.
The strongest predictor of a metronidazole prescription was digestive symptoms — things like diarrhea, stomach pain, or nausea. Patients with digestive complaints were more than 8 times more likely to receive metronidazole than those without. Genitourinary symptoms (related to the bladder, kidneys, or reproductive organs) raised the odds nearly 7-fold. Skin lesions also increased the likelihood.
That pattern makes clinical sense — these are exactly the kinds of problems metronidazole is designed to treat.
But here's the part worth examining more closely.
Private vs. Public — A Notable Gap
Patients seen in private clinics were more than twice as likely to receive a metronidazole prescription compared to those seen in public clinics. That gap held up even after researchers accounted for other factors like symptoms and patient age.
Why does it matter which type of clinic you go to? Private clinics in many low-income countries operate differently from public ones — they may face different economic pressures, have different staffing (including more non-physician prescribers like nurses), and have less access to diagnostic tools. Some research suggests that financial incentives can drive higher prescription rates in private settings.
This doesn't mean every private clinic prescription was inappropriate. But the gap is a signal worth investigating.
What This Tells Us — and What It Doesn't
The study identified who was getting metronidazole and in what circumstances. What it could not do is judge whether each prescription was appropriate. Without diagnostic results — like stool tests, cultures, or imaging — it's impossible to say how many of those gut complaints were truly caused by bacteria that metronidazole would treat versus viral infections or other causes where antibiotics don't help.
Most prescriptions in this setting are made by nurses, who are the backbone of primary care in many parts of West Africa. Nurses are skilled clinicians, but they often lack access to the same diagnostic tools available in hospitals, which means prescribing decisions sometimes have to be made based on symptoms alone.
What This Means for Patients
If you live in or travel to regions where antibiotic prescribing is common without lab confirmation, it's worth knowing that not all antibiotic prescriptions are always necessary. Taking antibiotics when they aren't needed doesn't help — and contributes to making them less effective for everyone over time.
If you're prescribed metronidazole, ask your doctor or nurse what infection they suspect and whether a test is available to confirm it.
The Limits of This Study
This was a single-year study in one city in Benin. Prescribing patterns can vary widely between countries, regions, and even individual clinics. The data came from written registers — meaning some visits may have been recorded incompletely. And without knowing patient outcomes, we can't say directly whether the prescriptions led to good or poor health results.
What Comes Next
Researchers are calling for follow-up studies that look at the appropriateness of metronidazole prescriptions — meaning whether patients actually had infections that called for the drug. Understanding what's driving higher prescribing in private facilities will also be key to designing better antibiotic stewardship programs tailored to the realities of primary care in West Africa.
The broader goal is to preserve the effectiveness of antibiotics like metronidazole for future generations — before resistance makes them a last resort instead of a first line of defense.