From the Guidelines
Gravol and Benadryl are distinct medications with different primary uses, despite both causing drowsiness as a side effect. Gravol, also known as dimenhydrinate, is primarily used to prevent and treat motion sickness, nausea, vomiting, and dizziness, whereas Benadryl, also known as diphenhydramine, is an antihistamine used to treat allergy symptoms like sneezing, itching, watery eyes, and runny nose, and is also used as a sleep aid and sometimes for motion sickness. Interestingly, dimenhydrinate (Gravol) contains diphenhydramine (Benadryl) combined with a stimulant called 8-chlorotheophylline, which helps counteract extreme drowsiness. According to a clinical practice guideline for the pharmacologic treatment of chronic insomnia in adults 1, diphenhydramine is not suggested as a treatment for sleep onset and sleep maintenance insomnia in adults, which implies that its use for sleep aid may not be the most effective or recommended option. Typical adult dosing for Gravol is 50-100 mg every 4-6 hours, while Benadryl is usually 25-50 mg every 4-6 hours. Both medications should be used with caution when driving or operating machinery due to their sedative effects, and neither should be combined with alcohol or other central nervous system depressants. Key differences in their use and composition highlight the importance of understanding their specific applications and potential interactions. Some of the key points to consider when choosing between Gravol and Benadryl include:
- Primary use: Gravol for motion sickness and Benadryl for allergy symptoms
- Composition: Gravol contains diphenhydramine plus a stimulant, while Benadryl is diphenhydramine alone
- Dosage: Gravol typically 50-100 mg every 4-6 hours, Benadryl typically 25-50 mg every 4-6 hours
- Side effects and interactions: both cause drowsiness and should be used cautiously with other CNS depressants or when operating machinery.
From the FDA Drug Label
Dimenhydrinate, an anti-nauseant/antiemetic, is the 8-chlorotheophylline salt of diphenhydramine. The main difference between Gravol (dimenhydrinate) and Benadryl (diphenhydramine) is that Gravol is a salt form of diphenhydramine, containing 8-chlorotheophylline, whereas Benadryl is pure diphenhydramine.
- Active ingredient: Gravol contains dimenhydrinate, which is composed of diphenhydramine and 8-chlorotheophylline, while Benadryl contains only diphenhydramine. 2
From the Research
Differences between Gravol and Benadryl
- Gravol, also known as dimenhydrinate, is an anti-emetic medication used to treat nausea, vomiting, and dizziness associated with motion sickness 3.
- Benadryl, also known as diphenhydramine, is an antihistamine medication used to treat allergic reactions, insomnia, and motion sickness 4, 5, 6.
Active Ingredients and Mechanisms
- Gravol works by blocking the action of histamine, a neurotransmitter that stimulates the vomiting center in the brain, and also has anticholinergic effects 3.
- Benadryl works by blocking the action of histamine, which causes blood vessels to dilate, leading to allergic symptoms, and also has sedative effects 4, 5, 6.
Side Effects and Abuse Liability
- Gravol has been reported to be abused for its euphoric and hallucinogenic effects, and has a potential for abuse liability 3.
- Benadryl has many side effects, including sedation, risk of toxicity in overdose, and cardiac toxicity, and its use is often inappropriately preferred over newer antihistamines with fewer side effects 4, 5.
Clinical Uses and Efficacy
- Gravol is commonly used to treat motion sickness, while Benadryl is used to treat a variety of conditions, including allergic reactions, insomnia, and motion sickness 3, 5, 6.
- Benadryl has been shown to be less effective than other antihistamines, such as cetirizine and fexofenadine, in treating acute allergic reactions, and its use as an adjuvant therapy for acute migraine has been found to be ineffective 5, 6.