The sufficient dimenhydrinate dose depends on a number of factors, including the product used, the age of the patient and the indication for which it is being used. Dimenhydrinate is an antihistamine drug usually used to treat nausea and vomiting due to motion sickness and vertigo. It may be known by different trade names in different countries according to manufacturer, and is usually available as an over-the-counter product. It is also found in some combination products.
Dimenhydrinate works by blocking the muscarinic and histamine receptors in the vomiting center in the brain, which reduces nausea and vomiting and dizziness associated with vertigo. The vomiting center, located in the hypothalamus of the brain, is the part of the body which causes nausea and vomiting and is triggered by numerous factors, both extrinsic and intrinsic. The drug may be available in both oral and injectable forms in some countries.
When determining the sufficient dimenhydrinate dose, the main factor to consider is the indication for which it is being used. Most commonly it is used short-term to treat or prevent motion sickness during air, sea or road travel. It is usually given about half an hour before the start of travel, with repeated doses every four to six hours until travel is completed. The children's dimenhydrinate dose is usually lower than that of adults, and is determined by weight. The recommended dose should never be exceeded to prevent the risk of adverse effects or overdose and all medications should be kept locked away, out of reach of children.
Regardless of the dimenhydrinate dose used, adverse effects may occur, although some are dose-dependent and may be more likely, or worse, at higher doses. Drowsiness, dry mouth and abdominal pain are amongst the side effects of dimenhydrinate that have been reported. Any adverse effects should be discussed with a health care professional. Due to the possibility of drowsiness after taking a dimenhydrinate dose, driving and the operation of heavy machinery should be avoided, as should concomitant intake of alcohol. Paradoxical effects, such as hyperactivity and hallucinations have also been reported, especially in children.
As with any medication, dimenhydrinate may interact with other medications. All prescription, over-the-counter, homeopathic and complementary medications should be discussed with the pharmacist before using. The drug may also be contraindicated in people with some underlying clinical conditions so these should also be discussed with a health care professional, as should pregnancy, desired pregnancy and lactation.