From the Guidelines
Phenergan (promethazine) is an effective medication for preventing and treating motion sickness, with a recommended dose of 25 mg for adults taken 30-60 minutes before travel, and 12.5-25 mg for children aged 2-12, not exceeding 100 mg and 75 mg daily, respectively. The medication works by blocking histamine receptors in the brain that trigger nausea and by reducing activity in the inner ear's balance center 1. According to a study published in 2012, the clinical effects of promethazine are evident within 5 minutes of intravenous administration, with a duration of action of 4 to 6 hours, and a plasma half-life of 9 to 16 hours 1.
Key Considerations
- The usual dose of promethazine is 12.5 to 25 mg, which can be repeated every 4-6 hours as needed during the journey 1.
- Side effects may include drowsiness, dry mouth, and blurred vision, making it important to avoid driving or operating machinery after taking it.
- For best results, take Phenergan before symptoms begin, stay hydrated during travel, and consider non-medication strategies like sitting where motion is minimized (middle of boat/plane, front seat of car) and focusing on the horizon.
- If motion sickness is severe or persistent despite medication, consult a healthcare provider for alternative options, such as ondansetron, a serotonin-5-hydroxytryptamine-3 antagonist, or scopolamine, an anticholinergic medication 1.
Alternative Options
- Other medications that may be used for motion sickness include meclizine, diphenhydramine, and ondansetron 1.
- Non-medication strategies, such as music therapy, aromatherapy, acupuncture, hypnosis, and relaxation techniques, may also be effective in reducing motion sickness symptoms 1.
From the FDA Drug Label
Motion Sickness The average adult dose is 25 mg taken twice daily The initial dose should be taken one-half to one hour before anticipated travel and be repeated 8 to 12 hours later, if necessary. On succeeding days of travel, it is recommended that 25 mg be given on arising and again before the evening meal. For children, promethazine hydrochloride tablets, syrup, or rectal suppositories, 12. 5 to 25 mg twice daily, may be administered.
The recommended dose of Fenergan (promethazine) for motion sickness is:
- Adults: 25 mg taken twice daily
- Children: 12.5 to 25 mg twice daily The initial dose should be taken one-half to one hour before anticipated travel and repeated 8 to 12 hours later, if necessary 2.
From the Research
Fenergan for Motion Sickness
- Fenergan, also known as promethazine, is a medication that can be used to treat motion sickness 3.
- It is a first-generation antihistamine that can help to prevent and treat nausea and vomiting associated with motion sickness 4, 5.
- However, it is important to note that promethazine can cause drowsiness and impair performance, as shown in a study where subjects who received promethazine injections had significant decrements in performance compared to those who received a placebo 3.
- In terms of its effectiveness, promethazine has been shown to be effective in reducing nausea and vomiting in some studies, but not as effective as other medications such as metoclopramide in others 6.
- It is also worth noting that ondansetron, a medication that is sometimes used to treat nausea and vomiting, is not effective in preventing or treating motion sickness 4, 5.
Comparison with Other Medications
- A study compared the effectiveness of ondansetron, metoclopramide, and promethazine in reducing nausea in adults, and found that promethazine was not significantly more effective than metoclopramide or ondansetron 6.
- Another study found that metoclopramide and promethazine were more effective than ondansetron in reducing nausea and vomiting in pregnant women, but the study was unable to provide conclusive evidence due to slow recruitment 7.
Side Effects and Considerations
- Promethazine can cause significant side effects, including drowsiness, fatigue, and impaired performance, which can be a concern for individuals who need to remain alert and focused while traveling 3.
- It is also important to consider the potential interactions between promethazine and other medications, as well as any underlying medical conditions that may affect its use 4, 5.