Vomiting that persists after initial fluid and electrolyte replacement is treated with antiemetics and other medications taken as needed: Vitamin B6 10 to 25 mg orally every 8 hours or every 6 hours Doxylamine 12.5 mg orally every 8 hours or every 6 hours (can be taken in addition to vitamin B6) Promethazine 12.5 to 25 mg orally, IM, or rectally every 4 to 8 hours Metoclopramide 5 to 10 mg IV or orally every 6 to 8 hours Ondansetron 8 mg orally or IM every 12 hours (for use before 10 weeks gestation, potential risks of congenital defects should be considered) Prochlorperazine 5 to 10 mg orally, IV, or IM every 6 hours OR 25 mg rectally 2 times a day, as needed After dehydration and acute vomiting resolve, small amounts of oral fluids are given.