Ranitidine (Zantac®)

Section 1.1

Midwives may independently prescribe, order and administer this drug.

(Zantac®) belongs to a group of drugs called histamine-2 blockers. Ranitidine works by reducing the amount of acid produced in the stomach.

Indications and Clinical Use:

Ranitidine is administered for the treatment of gastro esophageal reflux disease (GERD), gastric ulcers, and hyperemesis (see CMBC’s Indications for Discussion, Consult and Transfer of Care). Ranitidine can be administered during pregnancy or labour for the treatment of GERD.


Hypersensitivity or known allergy to Ranitidine.

Warnings and Precautions:

Do not mix clindamycin in same syringe, due to physical incompatibility. Caution should be exercised when administering ranitidine to patients with hepatic dysfunction since ranitidine is metabolized in the liver. If breastfeeding and still experiencing severe GERD after one month post-delivery, consideration should be given to referral for further medical work-up.




Category L2 – Limited Human Data – Probably Compatible

Ranitidine is excreted into human milk in concentrations exceeding those found in plasma. There have been no reported adverse effects in the newborn via milk. Although ranitidine is concentrated in milk, the overall dose is less than therapeutic. Ranitidine is used therapeutically in pediatric patients including infants.

Adverse Reactions: (infrequent)

Headache, dizziness, nausea, stomach upset and diarrhea.

Dosage and Administration:

Adult Oral: 150 mg twice daily or 300 mg once daily at bedtime;
IV/IM: 50 mg, IV infused over 15-30 minutes, or give direct IV over a minimum of 5 minutes, or IM, every 8 hours. (Comes as premixed minibag of 50 mg/50 mL, or 25 mg/mL injection).

Onset of Action:

Oral: 1-3 hours to peak level; IM dose – Within 15 minutes; IV – onset 5-10 min.


2-3 hours