STI Standards

Midwives may independently prescribe, order, and administer drugs in the community, hospital or other sites of midwifery practice to treat sexually transmitted infections for clients in case, as designated under specialized practice certification. Midwives without specialized practice certification in sexually transmitted infections management are required to refer their clients to an appropriate health care practitioner for treatment. 

Erythromycin is a macrolide anti-infective antibiotic used in the treatment of gram-positive, gram-negative and other microorganisms. Erythromycin acts by inhibition of protein synthesis and binding susceptible organisms.

Indications and Clinical Use:

For treatment of asymptomatic or symptomatic chlamydia trachomatis in pregnancy and the postpartum. (Please refer to the CMBC Standards, Limits and Conditions for Prescribing, Ordering and Administering Drugs).


Documented hypersensitivity or allergy to Erythromycin or any component of the formulation.

Warnings and Precautions:

Use with caution in those with liver disease. Use should be discontinued with nausea, vomiting or fever. Macrolides have been associated with rare QTc prolongation and ventricular arrhythmias. Prolonged use may result in fungal or bacterial superinfection, including C. difficile-associated diarrhea (CDAD) and pseudomembranous colitis; CDAD has been observed >2 months post-antibiotic treatment.

Breastfed infants may develop vomiting, diarrhea and/or rash. Modification of bowel flora and allergic sensitization of the infant may occur.


Compatible (Excludes Estolate Salt). No evidence of developmental toxicity with Erythromycin has been reported.


Limited Data – probably compatible.
This medication is considered suitable in lactation, the relative infant dose is less than 2%.

Adverse Reactions:

Upset stomach, nausea, vomiting, hepatitis, ototoxicity.

Dosage and Administration:

Chlamydia Trachomatis:
Erythromycin: 500 mg orally every 6 hours (qid) for 7 days or if not tolerated;
Erythromycin: 250 mg orally every 6 hours (qid) for 14 days.

Onset of Action:

Oral: Immediate release; may be taken with food to decrease gastrointestinal upset.

Duration of Action:

Peak serum concentrations usually attained within 2–4 hours.
Half-life: 1.5-2 hours.