Gravol (Dimenhydrinate) Indications
Gravol (dimenhydrinate) is FDA-approved for the prevention and treatment of nausea, vomiting, and vertigo associated with motion sickness, and is also considered a safe first-line antiemetic for nausea and vomiting of pregnancy. 1, 2
Primary Indications
Motion Sickness
- Prevention and treatment of motion sickness symptoms including nausea, vomiting, and vertigo under natural conditions (air, sea, and land transportation) 1
- Dimenhydrinate prevents motion sickness symptoms in approximately 40% of susceptible individuals compared to 25% with placebo, representing moderate-certainty evidence 3
- Works by suppressing the central emetic center to relieve nausea and vomiting 4
Vertigo
- Treatment of vertigo symptoms regardless of etiology 1
- Dimenhydrinate demonstrates similar efficacy to metoclopramide in reducing vertigo symptoms in emergency department settings, with significant VAS score reductions within 30 minutes 5
- Significantly reduces vertigo induced by caloric stimulation and suppresses both caloric and postrotatory nystagmus 6
Nausea and Vomiting of Pregnancy
- Safe first-line pharmacologic antiemetic therapy for persistent nausea and vomiting of pregnancy refractory to non-pharmacologic measures 2
- Recommended by the American College of Obstetricians and Gynecologists (ACOG) as a safe H1-receptor antagonist for use during pregnancy 2
- Should be used after initial trials of dietary modifications, ginger, and vitamin B6 (pyridoxine) 2
Important Safety Considerations and Contraindications
Pediatric Population
- Children under 6 years should NOT receive over-the-counter antihistamines including dimenhydrinate due to potential toxicity and safety concerns 4
- Between 1969-2006, there were 69 fatalities associated with antihistamines in children under 6 years, with 41 deaths in children under 2 years 4
- For children who cannot take antihistamines, prioritize non-pharmacological approaches such as distraction techniques and audio-visual entertainment 4
Pregnancy and Lactation
- Pregnancy Category B: reproduction studies show no evidence of fetal harm, though use should be reserved for when clearly needed 1
- May have oxytocic effects during labor; caution advised when this effect is unwanted 1
- Small amounts excreted in breast milk; decision to discontinue nursing or drug should consider importance to mother 1
Common Adverse Effects
- Sedation occurs in approximately 66% of patients compared to 44% with placebo 3
- Patients should be cautioned against operating automobiles or dangerous machinery due to drowsiness risk 1
- May cause blurred vision and impaired cognition, though rates are similar to placebo 3
Clinical Pitfalls to Avoid
- Do not use for long-term vestibular suppression as it interferes with central compensation in peripheral vestibular conditions and prevents natural adaptation to motion 4
- Avoid combining multiple motion sickness medications due to overdose risk and increased adverse effects 4
- Watch for paradoxical behavioral disinhibition, especially in younger children 4
- Monitor for anticholinergic side effects including hypotension in susceptible patients 5
Dosing Considerations
- For motion sickness prevention, administer before exposure to motion stimuli for optimal efficacy 1
- Maximum antimotion sickness effect achieved approximately 120 minutes after administration 7
- Efficacy comparable to other first-generation antihistamines and demonstrates similar effectiveness to metoclopramide for vertigo treatment 5