Antibiotics (common outpatient)
Cochrane reviews found antibiotics helped sinusitis, sore throat and children's ear infections only slightly against placebo, did not help colds or overall bronchitis recovery, and clearly helped bladder infections in women. Doxycycline after sex cut chlamydia and syphilis. Side effects such as diarrhea and rash were common, and antibiotics were linked to C. difficile, gut microbiome changes and resistance.
- Status
- Prescription drugs in the US. Amoxicillin, amoxicillin-clavulanate, azithromycin, doxycycline and cephalexin are FDA-approved for a range of bacterial infections, including respiratory, ear, skin and urinary infections, with the uses differing by drug. Doxycycline is also labeled as add-on treatment for severe acne. Doxycycline after sex to prevent sexually transmitted infections is off-label.
- Also called
- amoxicillin, Amoxil, amoxicillin-clavulanate, amoxicillin and clavulanate potassium, Augmentin, co-amoxiclav, azithromycin, Zithromax, Z-Pak, Zmax, doxycycline, Vibramycin, Doryx, Acticlate, Monodox, Oracea, doxy-PEP, cephalexin, Keflex, penicillins, macrolides, tetracyclines, cephalosporins
- Taken for
- sinus infection, sore throat, strep throat, bronchitis, chest cold, cough, common cold, ear infection, bladder infection, urinary tract infection, acne, COPD flare-ups, preventing sexually transmitted infections, green mucus
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Shown to help7
- StrongShown to cure slightly more adults with acute sinusitis than placebo, 5 to 11 more per 100, while 13 more per 100 had side effects.
- StrongShown to cut chlamydia and syphilis by about three quarters with doxycycline after sex, mostly in men who have sex with men, with a smaller or no effect on gonorrhea.
- ModerateShown to reduce sore throat at day 3 against placebo, with fewer than 6 treated for one extra person without it, though 82% on placebo were symptom-free by one week.
- ModerateShown to slightly reduce children's ear pain at 2 to 3 days, 20 treated for one fewer in pain, but not at 24 hours, with extra vomiting, diarrhea or rash.
- ModerateShown to cure uncomplicated bladder infections in women far more often than placebo, about 5 times the odds, while amoxicillin-clavulanate cured fewer than ciprofloxacin, 58% against 77%.
- ModerateShown to reduce acne lesions, with doxycycline beating placebo in a 16-week trial and matching azithromycin in meta-analyses. Spironolactone did better than doxycycline in adult women.
- ModerateShown to cut COPD flare-ups with long-term macrolides such as azithromycin, from 61% to 47% of people, 8 treated for one fewer, with hearing loss reported on azithromycin.
Reported risks13
- StrongShown to raise side effects such as diarrhea, vomiting and rash against placebo, one extra person affected for every 8 to 24 treated, depending on the infection.Common
- LimitedMixed results: one cohort linked azithromycin to 47 extra cardiovascular deaths per million courses, while a Danish cohort found no rise against penicillin. The label warns of QT prolongation.Rare
- ModerateLinked to C. difficile infection outside hospital, about 2.7 times the odds on penicillins or macrolides and 5.7 on cephalosporins, with no link for tetracyclines.How often is not known
- ModerateShown to change the gut microbiome, often lowering bacterial diversity and beneficial bacteria, with some changes lasting a year or more after certain antibiotics.How often is not known
- ModerateLinked to resistant bacteria in the person treated, about 2.5 times the odds within 2 months for urinary bacteria, lasting up to 12 months.How often is not known
- ModerateThe labels warn of serious, occasionally fatal allergic reactions. In proven penicillin allergy, cross-reaction to cephalosporins ranged from 2% to 16%, highest with a shared side chain.How often is not known
- ModerateLinked to hearing loss when azithromycin was taken long-term to prevent COPD flare-ups, often reversible. The label lists hearing loss and tinnitus.How often is not known
- ModerateMixed results: the amoxicillin label says it may reduce birth control pill efficacy, while a systematic review found no evidence that non-rifamycin antibiotics reduce hormonal contraception.How often is not known
- LimitedThe labels warn of liver injury, including cholestatic jaundice with amoxicillin-clavulanate and severe, sometimes fatal hepatotoxicity with azithromycin.How often is not known
- LimitedThe doxycycline label warns of exaggerated sunburn, irritation and ulcers of the esophagus, and raised pressure inside the skull, which can threaten vision.How often is not known
- LimitedThe label warns tetracyclines such as doxycycline may permanently stain teeth when taken in the second half of pregnancy, infancy or childhood up to age 8.How often is not known
- LimitedThe labels report that a high percentage of people with mononucleosis who take amoxicillin develop a red skin rash.How often is not known
- LimitedThe labels warn amoxicillin, azithromycin and doxycycline can raise warfarin's effect, antacids and iron block doxycycline, and azithromycin adds to other QT-prolonging drugs.How often is not known
What people take it for, and what was found
Shown to help7
Acute sinus infection in adults
Shown to cure slightly more adults with acute sinusitis than placebo, 5 to 11 more per 100, while 13 more per 100 had side effects.
Compared with placebo or no treatment [1]; placebo [2]
The numbers and sources
- Effect
- Without antibiotics, 46% were cured at 1 week and 64% at 14 days. With a clinical diagnosis, antibiotics raised cure (OR 1.25, 95% CI 1.02 to 1.54), a number needed to treat of 19, and 10 when the diagnosis was confirmed on imaging. Side effects were more frequent (OR 2.21), one extra person harmed for every 8 treated [1]. In individual patient data from 9 trials, 15 adults needed antibiotics for one more to be cured, and common signs and symptoms could not pick out who would benefit [2].
- Population
- 3,057 adults in 15 trials in ambulatory care [1]; 2,547 adults in 9 trials [2].
- Sources
- [1], [2]
- Caveats
- Children, people with weakened immune systems and severe sinusitis were not studied [1]. The trials used a range of antibiotics.
Sore throat
Shown to reduce sore throat at day 3 against placebo, with fewer than 6 treated for one extra person without it, though 82% on placebo were symptom-free by one week.
Compared with placebo or no treatment [3]
The numbers and sources
- Effect
- Sore throat at day 3 was less frequent on antibiotics (RR 0.70, 95% CI 0.60 to 0.80), and at 1 week (RR 0.50), when the number needed to treat was 18. Fever at day 3 did not differ (RR 0.75, 95% CI 0.53 to 1.07). Antibiotics lowered ear infections within 14 days (Peto OR 0.21), quinsy (Peto OR 0.16) and acute rheumatic fever (Peto OR 0.36), but not sinusitis [3].
- Population
- 15,337 cases of sore throat in 29 trials, mostly adults [3].
- Sources
- [3]
- Caveats
- Most trials were run in the 1950s, when complications such as rheumatic fever were far more frequent. Few trials separated bacterial from viral sore throat, and harms were poorly reported [3].
Ear infections in children
Shown to slightly reduce children's ear pain at 2 to 3 days, 20 treated for one fewer in pain, but not at 24 hours, with extra vomiting, diarrhea or rash.
Compared with placebo [7]; waiting to see if antibiotics were needed [7]
The numbers and sources
- Effect
- Pain at 24 hours did not differ (RR 0.89, 95% CI 0.78 to 1.01), but was a third less frequent at 2 to 3 days (RR 0.71, number needed to treat 20). Abnormal tympanometry at 2 to 4 weeks (RR 0.83), eardrum perforation (RR 0.43) and infection in the other ear (RR 0.49) fell, and late recurrences did not change. Vomiting, diarrhea or rash rose (RR 1.38, one extra per 14 treated). Against waiting, immediate antibiotics did not lower pain at 3 to 7 days (RR 0.75) and raised these side effects (RR 1.87) [7].
- Population
- 3,401 children in 13 placebo trials and 1,556 in 6 trials of immediate antibiotics against waiting, all in high-income countries [7].
- Sources
- [7]
- Caveats
- Serious complications were rare in both groups. Results may not apply where complications are more common [7].
Bladder infection in women
Shown to cure uncomplicated bladder infections in women far more often than placebo, about 5 times the odds, while amoxicillin-clavulanate cured fewer than ciprofloxacin, 58% against 77%.
Compared with placebo [8]; ciprofloxacin [9]
The numbers and sources
- Effect
- Clinical success (OR 4.81, 95% CI 2.51 to 9.21), cure (OR 4.67) and clearing bacteria at the end of treatment (OR 10.67) were more likely on antibiotics than placebo, and reinfection or relapse less likely (OR 0.27). Adverse events were more frequent (OR 1.64), and kidney infection did not differ [8]. A 3-day course of amoxicillin-clavulanate cured 58% against 77% on ciprofloxacin, and 60% against 77% even with susceptible bacteria, with vaginal E. coli remaining in 45% against 10% [9].
- Population
- 1,062 nonpregnant adult women with confirmed cystitis in 4 trials [8]; 370 women aged 18 to 45 [9].
- Sources
- [8], [9]
- Caveats
- The placebo trials did not single out the drugs on this page [8].
Acne (doxycycline)
Shown to reduce acne lesions, with doxycycline beating placebo in a 16-week trial and matching azithromycin in meta-analyses. Spironolactone did better than doxycycline in adult women.
Compared with placebo and doxycycline 100 mg [10]; azithromycin [11][12]; isotretinoin and other treatments [12]; spironolactone [13]
The numbers and sources
- Effect
- Modified-release doxycycline 40 mg was superior to placebo for inflammatory lesions and success rate over 16 weeks, comparable to doxycycline 100 mg, with fewer drug-related side effects than 100 mg [10]. Azithromycin pulses and daily doxycycline did not differ in remaining lesions or assessments at 12 weeks, with more stops for side effects on doxycycline [11]. Across 23 trials, doxycycline matched azithromycin (OR 1.28, 95% CI 0.54 to 3.04), while other treatments such as isotretinoin improved acne grading scores more, and doxycycline had more gastrointestinal and skin side effects [12]. In adult women with moderate acne, spironolactone was more successful than doxycycline at 4 and 6 months [13].
- Population
- 662 people aged 12 or older with moderate to severe acne [10]; 906 patients in 6 trials [11]; 2,672 patients in 23 trials [12]; 133 women [13].
- Sources
- [10], [11], [12], [13]
- Caveats
- The placebo trial abstract gives no effect sizes [10], and heterogeneity was high in [12].
Preventing COPD flare-ups with long-term azithromycin
Shown to cut COPD flare-ups with long-term macrolides such as azithromycin, from 61% to 47% of people, 8 treated for one fewer, with hearing loss reported on azithromycin.
Compared with placebo [14]
The numbers and sources
- Effect
- People with one or more exacerbations fell from 61% to 47% (OR 0.57, 95% CI 0.42 to 0.78), a number needed to treat of 8 over 3 to 12 months, and yearly exacerbations fell (rate ratio 0.67). Quality of life improved by less than the clinically important margin (MD -1.94 on the St George's questionnaire). Hospital admissions, lung function, serious adverse events and deaths did not differ. Azithromycin was linked to hearing loss, often reversible [14].
- Population
- 3,932 people in 14 trials, mean age 65 to 72, mostly moderate to severe COPD with frequent flare-ups [14].
- Sources
- [14]
- Caveats
- The benefit applies to macrolides taken at least three times a week. Resistance rose in some studies [14].
Doxycycline after sex to prevent sexually transmitted infections
Shown to cut chlamydia and syphilis by about three quarters with doxycycline after sex, mostly in men who have sex with men, with a smaller or no effect on gonorrhea.
Compared with standard care without doxycycline [15][16]; no prophylaxis [17]
The numbers and sources
- Effect
- In people on HIV prevention pills, a sexually transmitted infection was found at 10.7% of quarterly visits on doxycycline 200 mg within 72 hours of sex and 31.9% on standard care (RR 0.34), with similar results in people living with HIV (RR 0.38). Tetracycline-resistant gonorrhea occurred in 5 of 13 cases on doxycycline and 2 of 16 on standard care [15]. Pooled trials found lower chlamydia (RR 0.22) and syphilis (RR 0.24) and a smaller drop in gonorrhea (RR 0.79) [16]. Another meta-analysis found chlamydia (RR 0.35) and syphilis (RR 0.23) lower and no significant effect on gonorrhea (RR 0.90) [17].
- Population
- 501 men who have sex with men and transgender women [15]; 1,278 participants in 3 trials [16]; 1,727 participants in 4 trials, 73% men who have sex with men [17].
- Sources
- [15], [16], [17]
- Caveats
- Open-label trials. Long-term effects on resistance remain uncertain [16][17].
Not shown to help2
Acute bronchitis and chest infections
Not shown to improve overall recovery from acute bronchitis, with cough about half a day shorter, and amoxicillin did not shorten bad symptoms in a 2,061-person trial.
The numbers and sources
- Effect
- The share clinically improved did not differ (RR 1.07, 95% CI 0.99 to 1.15). Cough was less frequent at follow-up (RR 0.64, a number needed to treat of 6) and lasted 0.46 days less. Adverse effects were more frequent (RR 1.20), one extra for every 24 treated [4]. In adults with a chest infection not suspected to be pneumonia, amoxicillin 1 g three times daily did not shorten moderately bad symptoms (HR 1.06, 95% CI 0.96 to 1.18). New or worse symptoms were 15.9% against 19.3% (number needed to treat 30), and nausea, rash or diarrhea one extra per 21 treated, including in people 60 or older [5].
- Population
- 5,099 people in 17 trials [4]; 2,061 adults in 12 European countries [5].
- Sources
- [4], [5]
- Caveats
- Frail older people with several conditions may have been left out of trials [4].
Common cold and green nasal discharge
Not shown to help the common cold or persisting colored nasal discharge against placebo, while adults given antibiotics for a cold had more side effects.
Compared with placebo [6]
The numbers and sources
- Effect
- Lack of cure or persistent cold symptoms did not differ (RR 0.83, 95% CI 0.60 to 1.14). Persisting purulent rhinitis did not differ (RR 0.73, 95% CI 0.47 to 1.13). Adverse effects were more frequent on antibiotics for colds (RR 1.8), in adults (RR 2.62) but not children (RR 0.91), and for purulent rhinitis (RR 1.46) [6].
- Population
- Up to 1,147 people in 6 common cold trials and 723 in 4 purulent rhinitis trials [6].
- Sources
- [6]
- Caveats
- Trials used various antibiotics and outcome measures, and some participants may have had chest or sinus infections [6].
Doses studied
The chest infection trial used amoxicillin 1 g three times daily for 7 days [5]. The bladder infection trial used amoxicillin-clavulanate 500/125 mg twice daily for 3 days [9]. The doxycycline sexual health trial used 200 mg within 72 hours after sex [15], and the acne trial used modified-release doxycycline 40 mg or doxycycline 100 mg once daily for 16 weeks [10]. The azithromycin label lists 500 mg on day 1 then 250 mg on days 2 to 5 for several infections, and 500 mg a day for 3 days for sinusitis [18]. The cephalexin label lists 250 mg every 6 hours or 500 mg every 12 hours for 7 to 14 days [19].
Risks
Reported risks11
Diarrhea, nausea and rash
Shown to raise side effects such as diarrhea, vomiting and rash against placebo, one extra person affected for every 8 to 24 treated, depending on the infection.
The numbers and sources
- How common
- Common: between 1 in 100 and 1 in 10 people.
- Effect
- Against placebo, side effects rose in sinusitis (OR 2.21, one extra per 8 treated) [1], children's ear infections (RR 1.38, one per 14) [7], bronchitis (RR 1.20, one per 24) [4] and colds (RR 1.8) [6]. Nausea, rash or diarrhea was one extra per 21 on amoxicillin [5]. In label trials, diarrhea or loose stools affected 9% on amoxicillin-clavulanate [20], and diarrhea 5% to 14% on azithromycin [18].
- Population
- Trial populations in [1][7][4][6][5]; label trials [20][18].
- Sources
- [1], [7], [4], [6], [5], [20], [18]
- Caveats
- The label rates have no placebo comparison.
C. difficile infection
Linked to C. difficile infection outside hospital, about 2.7 times the odds on penicillins or macrolides and 5.7 on cephalosporins, with no link for tetracyclines.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- Against no antibiotic, community C. difficile infection was linked to penicillins (OR 2.71, 95% CI 1.75 to 4.21), macrolides (OR 2.65), and cephalosporins with related drugs (OR 5.68), and not to tetracyclines (OR 0.92, 95% CI 0.61 to 1.40) [21]. Each label warns that C. difficile diarrhea has been reported with nearly all antibacterial drugs, ranging from mild diarrhea to fatal colitis [22][19][18][23].
- Population
- 7 observational studies in people outside hospital [21]; label statements [22][19][18][23].
- Sources
- [21], [22], [19], [18], [23]
- Caveats
- Observational studies with no absolute rate in the abstract [21].
Changes to the gut microbiome
Shown to change the gut microbiome, often lowering bacterial diversity and beneficial bacteria, with some changes lasting a year or more after certain antibiotics.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- Many studies reported lower bacterial diversity during treatment. Amoxicillin, amoxicillin-clavulanate, cephalosporins and macrolides raised Enterobacteriaceae other than E. coli. Macrolides strongly reduced anaerobic bacteria, while macrolides and doxycycline reduced Enterococcus. Many antibiotics reduced butyrate-producing bacteria. The longest-lasting changes were after ciprofloxacin, clindamycin and clarithromycin with metronidazole, up to four years [24].
- Population
- 2,076 participants and 301 controls in 129 studies [24].
- Sources
- [24]
- Caveats
- A systematic review without pooled numbers. Health effects of these changes were not measured [24].
Resistance in the person treated
Linked to resistant bacteria in the person treated, about 2.5 times the odds within 2 months for urinary bacteria, lasting up to 12 months.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- After a primary care antibiotic, resistance in urinary bacteria rose (OR 2.5, 95% CI 2.1 to 2.9 within 2 months, 1.33 within 12 months), and in respiratory bacteria (OR 2.4 at both times). Longer and repeated courses were linked to more resistance [25]. Tetracycline-resistant gonorrhea occurred in 5 of 13 cases on doxycycline after sex and 2 of 16 on standard care [15], and resistance rose in some long-term COPD trials [14].
- Population
- 14,348 participants in 5 urinary and 2,605 in 7 respiratory studies [25]; trial populations [15][14].
- Sources
- [25], [15], [14]
- Caveats
- Mostly observational [25].
Allergic reactions and penicillin to cephalosporin cross-reactions
The labels warn of serious, occasionally fatal allergic reactions. In proven penicillin allergy, cross-reaction to cephalosporins ranged from 2% to 16%, highest with a shared side chain.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- The amoxicillin label reports serious and occasionally fatal anaphylaxis with penicillins, and the cephalexin label reports rash, hives, anaphylaxis and severe skin reactions [22][19]. In people with confirmed penicillin allergy, cross-reactivity was 16.45% for aminocephalosporins, which share an identical side chain with a penicillin, 5.60% for intermediate similarity and 2.11% for low similarity, and 0.87% for carbapenems [26].
- Population
- Label statements [22][19]; 1,269 penicillin-allergic patients in 21 studies [26].
- Sources
- [22], [19], [26]
- Caveats
- Cross-reactivity rates apply to people with proven allergy, not to everyone with a penicillin allergy label [26].
Hearing loss with long-term azithromycin
Linked to hearing loss when azithromycin was taken long-term to prevent COPD flare-ups, often reversible. The label lists hearing loss and tinnitus.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- In COPD prophylaxis trials, azithromycin was associated with significant hearing loss in the treatment group, in many cases reversible or partly reversible [14]. The label lists hearing loss, deafness and tinnitus among reported reactions [18].
- Population
- COPD trial participants [14]; postmarketing reports [18].
- Sources
- [14], [18]
- Caveats
- The review abstract gives no rate.
Liver injury
The labels warn of liver injury, including cholestatic jaundice with amoxicillin-clavulanate and severe, sometimes fatal hepatotoxicity with azithromycin.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- Hepatitis and cholestatic jaundice have been associated with amoxicillin-clavulanate, usually reversible, with deaths reported mainly in people with serious underlying disease or other medicines. It is contraindicated after past liver problems on the drug [20]. Severe and sometimes fatal liver toxicity has been reported with azithromycin [18].
- Population
- Label statements and reports [20][18].
- Sources
- [20], [18]
- Caveats
- No rate given.
Doxycycline: sunburn, swallowing irritation and pressure in the head
The doxycycline label warns of exaggerated sunburn, irritation and ulcers of the esophagus, and raised pressure inside the skull, which can threaten vision.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- The label reports photosensitivity as an exaggerated sunburn reaction, advises enough fluid to reduce esophageal irritation and ulceration, and reports intracranial hypertension with headache, blurred or double vision and possible permanent vision loss, noting overweight women of childbearing age as at higher risk [23].
- Population
- Label statements [23].
- Sources
- [23]
- Caveats
- No rates given.
Doxycycline: tooth staining in children and pregnancy
The label warns tetracyclines such as doxycycline may permanently stain teeth when taken in the second half of pregnancy, infancy or childhood up to age 8.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- Use of tetracycline-class drugs during tooth development, from the last half of pregnancy through infancy and childhood to age 8, may cause permanent yellow-gray-brown discoloration, more often with long-term use [23].
- Population
- Label statement [23].
- Sources
- [23]
- Caveats
- No rate given.
Rash with amoxicillin during mononucleosis
The labels report that a high percentage of people with mononucleosis who take amoxicillin develop a red skin rash.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- A high percentage of patients with mononucleosis who receive amoxicillin develop an erythematous skin rash, and the labels advise against its use in mononucleosis [22][20]. Allopurinol with amoxicillin raises the risk of rash [22].
- Population
- Label statements [22][20].
- Sources
- [22], [20]
- Caveats
- The labels give no percentage.
Interactions with blood thinners and other drugs
The labels warn amoxicillin, azithromycin and doxycycline can raise warfarin's effect, antacids and iron block doxycycline, and azithromycin adds to other QT-prolonging drugs.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- Abnormal prolongation of prothrombin time has been reported with amoxicillin and oral anticoagulants [22]. Azithromycin with warfarin may increase clotting times, and the label urges caution with other drugs that prolong the QT interval [18]. Anticoagulant doses may need lowering with doxycycline, and antacids with aluminum, calcium or magnesium, bismuth subsalicylate and iron impair its absorption [23].
- Population
- Label statements [22][18][23].
- Sources
- [22], [18], [23]
- Caveats
- Label warnings, without measured rates.
Mixed results2
Azithromycin and heart rhythm or cardiac death
Mixed results: one cohort linked azithromycin to 47 extra cardiovascular deaths per million courses, while a Danish cohort found no rise against penicillin. The label warns of QT prolongation.
The numbers and sources
- How common
- Rare: fewer than 1 in 1,000 people.
- Effect
- During 5 days of azithromycin, cardiovascular death was higher than with no antibiotic (HR 2.88) or amoxicillin (HR 2.49), an estimated 47 extra deaths per million courses and 245 in people at highest heart risk [27]. In Danish adults aged 18 to 64, 17 cardiovascular deaths occurred during 1,102,419 azithromycin episodes, and risk did not differ from penicillin V (rate ratio 0.93, 95% CI 0.56 to 1.55) [28]. The label reports QT prolongation and torsades de pointes and notes observational studies showing about twice the short-term risk of cardiovascular death [18].
- Population
- Tennessee Medicaid patients with 347,795 azithromycin prescriptions [27]; Danish adults [28].
- Sources
- [27], [28], [18]
- Caveats
- Observational. The two cohorts differed in age and baseline heart risk.
Interaction with birth control pills
Mixed results: the amoxicillin label says it may reduce birth control pill efficacy, while a systematic review found no evidence that non-rifamycin antibiotics reduce hormonal contraception.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- Two studies found no difference in pregnancy rates in women taking oral contraceptives with and without non-rifamycin antibiotics. No study found changes in ovulation suppression or breakthrough bleeding, and no progestin level fell [29]. The amoxicillin label states amoxicillin may reduce the efficacy of oral contraceptives [22].
- Population
- 29 studies of pills, emergency contraception and the vaginal ring [29]; label statement [22].
- Sources
- [29], [22]
- Caveats
- Data were limited for some antibiotic classes [29]. Rifampin, not on this page, does lower contraceptive hormone levels.
Claims tested and not found
- That antibiotics help a common cold. Cure or persistent symptoms did not differ from placebo (RR 0.83) [6].
- That green or colored nasal discharge means antibiotics will help. Persisting purulent rhinitis did not differ from placebo (RR 0.73) [6].
- That antibiotics speed recovery from acute bronchitis or a chest cold. Overall improvement did not differ (RR 1.07) [4], and amoxicillin did not shorten symptoms in 2,061 adults [5].
- That antibiotics ease a child's ear pain within a day. Pain at 24 hours did not differ from placebo (RR 0.89) [7].
- That common antibiotics make birth control pills fail. Pregnancy rates, ovulation and progestin levels did not change with non-rifamycin antibiotics [29].
Sources
- Lemiengre MB, van Driel ML, Merenstein D, et al. Antibiotics for acute rhinosinusitis in adults. Cochrane Database of Systematic Reviews. 2018. https://doi.org/10.1002/14651858.CD006089.pub5
- Young J, De Sutter A, Merenstein D, et al. Antibiotics for adults with clinically diagnosed acute rhinosinusitis: a meta-analysis of individual patient data. The Lancet. 2008. https://doi.org/10.1016/S0140-6736(08)60416-X
- Spinks A, Glasziou PP, Del Mar CB. Antibiotics for treatment of sore throat in children and adults. Cochrane Database of Systematic Reviews. 2021. https://doi.org/10.1002/14651858.CD000023.pub5
- Smith SM, Fahey T, Smucny J, et al. Antibiotics for acute bronchitis. Cochrane Database of Systematic Reviews. 2017. https://doi.org/10.1002/14651858.CD000245.pub4
- Little P, Stuart B, Moore M, et al. Amoxicillin for acute lower-respiratory-tract infection in primary care when pneumonia is not suspected: a 12-country, randomised, placebo-controlled trial. The Lancet Infectious Diseases. 2013. https://doi.org/10.1016/S1473-3099(12)70300-6
- Kenealy T, Arroll B. Antibiotics for the common cold and acute purulent rhinitis. Cochrane Database of Systematic Reviews. 2025. https://doi.org/10.1002/14651858.CD000247.pub4
- Venekamp RP, Sanders SL, Glasziou PP, et al. Antibiotics for acute otitis media in children. Cochrane Database of Systematic Reviews. 2023. https://doi.org/10.1002/14651858.CD000219.pub5
- Falagas ME, Kotsantis IK, Vouloumanou EK, et al. Antibiotics versus placebo in the treatment of women with uncomplicated cystitis: a meta-analysis of randomized controlled trials. Journal of Infection. 2009. https://doi.org/10.1016/j.jinf.2008.12.009
- Hooton TM, Scholes D, Gupta K, et al. Amoxicillin-clavulanate vs ciprofloxacin for the treatment of uncomplicated cystitis in women: a randomized trial. JAMA. 2005. https://doi.org/10.1001/jama.293.8.949
- Moore A, Ling M, Bucko A, Manna V, Rueda MJ. Efficacy and Safety of Subantimicrobial Dose, Modified-Release Doxycycline 40 mg Versus Doxycycline 100 mg Versus Placebo for the treatment of Inflammatory Lesions in Moderate and Severe Acne: A Randomized, Double-Blinded, Controlled Study. Journal of Drugs in Dermatology. 2015. https://pubmed.ncbi.nlm.nih.gov/26091383/
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