What is the recommended dosage of Gravol (dimenhydrinate) for nausea and vomiting?

From the Guidelines

The recommended dosage of Gravol (dimenhydrinate) for nausea and vomiting is 50-100 mg every 4-6 hours as needed, not exceeding 400 mg in 24 hours, as per the most recent guidelines 1. When considering the treatment of nausea and vomiting, it's essential to assess the severity of symptoms, which can be quantified using a scoring system like the Motherisk Pregnancy Unique Quantification of Emesis score, as seen in Table 1 of the study 1.

Key Considerations

• Gravol works by blocking histamine H1 receptors and affecting the vestibular system in the inner ear, which helps reduce nausea and vomiting.
• It's available in various forms, including tablets, liquid, and suppositories.
• Common side effects include drowsiness and dry mouth, so it's crucial to avoid driving or operating machinery after taking it.
• If you're pregnant, breastfeeding, or have certain medical conditions like glaucoma or prostate problems, it's essential to consult your healthcare provider before using Gravol, as the study suggests that doxylamine is US Food and Drug Administration–approved and recommended by the American College of Obstetricians and Gynecologists (ACOG) for persistent NVP refractory to non-pharmacologic therapy 1.

Dosage Guidelines

• For adults and children 12 years and older: 50-100 mg every 4-6 hours as needed, not exceeding 400 mg in 24 hours.
• For children 6-12 years old: 25-50 mg every 6-8 hours, not exceeding 150 mg daily.
• For children 2-6 years old: 12.5-25 mg every 6-8 hours, not exceeding 75 mg daily. It's crucial to follow these guidelines and consult a healthcare provider if symptoms persist or worsen, as early intervention and treatment may help prevent progression to hyperemesis gravidarum (HG) 1.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION Dimenhydrinate in the injectable form is indicated when the oral form is impractical. Adults Nausea or vomiting may be expected to be controlled for approximately 4 hours with 50 mg, and prevented by a similar dose every 4 hours The recommended dosage of Gravol (dimenhydrinate) for nausea and vomiting is:

• 50 mg every 4 hours for adults, as this dose is expected to control nausea or vomiting for approximately 4 hours 2
• A maximum dose of 100 mg every 4 hours may be given in conditions where drowsiness is not objectionable or is even desirable 2
• For pediatric patients, the dose is 1.25 mg/kg of body weight or 37.5 mg/m2 of body surface area, administered four times daily, with a maximum dose not exceeding 300 mg daily 2

From the Research

Dosage Information for Gravol (Dimenhydrinate)

• The recommended dosage of Gravol (dimenhydrinate) for nausea and vomiting is not explicitly stated in the provided studies, but we can look at the dosages used in various studies:
  • In the study 3, dimenhydrinate was given as an oral, long-acting formulation containing 25 mg of immediate and 50 mg of sustained release drug.
  • In the study 4, 50 mg of dimenhydrinate was given intravenously for 15 minutes.
  • In the study 5, rectal dimenhydrinate was used, but the exact dosage is not specified.

Usage Guidelines

• According to the study 6, patients with acute ingestions of less than a toxic dose of dimenhydrinate, or chronic exposures to dimenhydrinate and no or mild symptoms, can be observed at home with instructions to call the poison center back if symptoms develop or worsen.
• The study 3 suggests that preoperative administration of an oral dose of long-acting dimenhydrinate can effectively reduce the incidence of vomiting in women undergoing elective outpatient gynecologic laparoscopy.
• The study 4 found that dimenhydrinate and metoclopramide have similar efficacy in reducing nausea and vertigo symptoms in the emergency department.
• The study 5 found that dimenhydrinate reduces the frequency of vomiting in children with mild dehydration, but the overall benefit is low.

Important Considerations

• The study 6 emphasizes the importance of considering the patient's condition, the length of time it will take to arrive at the emergency department, and the presence of co-ingestants when deciding on a course of action.
• The study 7 highlights the potential for dimenhydrinate to be abused and the need for careful management of withdrawal symptoms.
• The study 5 notes that dimenhydrinate does not improve oral rehydration and clinical outcome in children with mild dehydration.