Amoxicillin Safety During Pregnancy
Amoxicillin is safe to use during pregnancy and is considered a first-line antibiotic treatment for pregnant women when clinically indicated. 1, 2
Safety Profile
- Amoxicillin is classified as Pregnancy Category B by the FDA, indicating no evidence of harm to the fetus in animal studies 2
- Reproduction studies in mice and rats at doses up to 2000 mg/kg (3-6 times the human dose) showed no evidence of fetal harm 2
- Penicillins, including amoxicillin, are considered among the safest antibiotic classes for use during pregnancy 1
- A population-based study found no increased risk of adverse pregnancy outcomes with amoxicillin exposure; in fact, birth weights were slightly higher (57g) in the amoxicillin-exposed group 3
Recommended Use During Pregnancy
Amoxicillin is recommended as a first-line treatment for pregnant women with:
- Dental infections
- Streptococcal infections
- Urinary tract infections
- Upper respiratory tract infections 1
Standard dosing for pregnant women: 500 mg orally three times daily for 5-7 days 1
Important Considerations
Physiological Changes
- Pregnancy causes increased glomerular filtration rate and total body volume, which may alter amoxicillin pharmacokinetics 4
- Dosage adjustments may be necessary in some cases to maintain therapeutic levels 4
Potential Side Effects
- Common side effects include gastrointestinal disturbances
- Rare but serious side effects may include hypersensitivity reactions 2
- Amoxicillin use by nursing mothers may lead to sensitization of infants, so caution should be exercised when administered to breastfeeding women 2
Drug Interactions
When prescribing amoxicillin during pregnancy, be aware of these potential interactions:
- Probenecid: Decreases renal tubular secretion of amoxicillin, resulting in increased blood levels 2
- Oral anticoagulants: May cause abnormal prolongation of prothrombin time 2
- Allopurinol: Concurrent use increases incidence of rashes 2
- Oral contraceptives: May reduce efficacy of combined oral estrogen/progesterone contraceptives 2
Alternatives for Penicillin-Allergic Patients
For pregnant patients with penicillin allergy:
- For those without history of anaphylaxis/angioedema/respiratory distress/urticaria: Cefazolin is recommended 5
- For those with high risk of anaphylaxis: Antimicrobial susceptibility testing should be ordered to determine appropriate alternatives 5
- Clindamycin is considered a safe alternative during pregnancy for those with severe penicillin allergy 1
Antibiotics to Avoid During Pregnancy
Several antibiotics should be avoided during pregnancy due to potential risks:
- Tetracyclines: Risk of tooth discoloration and bone growth inhibition 1
- Fluoroquinolones: Risk of cartilage damage 1
- Trimethoprim-sulfamethoxazole: Increased risk of birth defects 1
- Aminoglycosides: Risk of ototoxicity and nephrotoxicity 1
Clinical Monitoring
- Assess for penicillin allergy before prescribing
- Monitor renal function in patients with impaired kidney function
- Evaluate clinical response within 48-72 hours of initiating therapy
- Repeat cultures after treatment for certain infections to confirm cure 1