Examples of potential dosages for ondansetron are as follows: Adults: 4 mg to 8 mg orally every 8 to 12 hours Children 6 months to 10 years: 8 to 15 kg, 2 mg orally; > 15 kg, 4 mg orally Nondrug measures Susceptible people should minimize exposure by positioning themselves where motion is the least (eg, in the middle of a ship close to water level, over the wings in an airplane).