Action and mechanism- [ANTIEMETIC], [HISTAMINERGIC (H-1) ANTAGONIST], [MUSCARIANIC (M) CHOLINERGIC ANTAGONIST]. Dimenhydrinate exerts an antiemetic effect probably due to the antagonism of central histamine H1 and muscarinic receptors. Caffeine decreases the sedative effect of dimenhydrinate. Indications- [MOTION TICKETOSIS]. Treatment of [NAUSEA] and [VOMITING] associated with [MOTION SICKNESS] during travel.- [VERTIGO]. DosageDosage:- Adults, oral: 1-2 tablets before the trip. This dose should be repeated every 3-4 hours for the duration of the trip. If motion sickness has already occurred, take 2 tablets in a single dose.- Children, oral: The safety and efficacy of this medicine in children have not been evaluated. Instructions for correct administrationIt is recommended to take this medicine preferably 1-2 hours before the trip, and if not possible, at least 30 minutes before. The doses should be repeated as often as necessary during the duration of the trip, respecting the recommended intervals.Contraindications- Hypersensitivity to any component of the medicine, including [XANTHINE ALLERGY].- [ASTHMA ATTACK].- [PORPHYRIA]. H1 antihistamines have been associated with the appearance of porphyric attacks.Precautions- [KIDNEY FAILURE]. Accumulation of dimenhydrinate may occur, because it and its metabolites are eliminated in the urine.- [LIVER FAILURE]. Dimenhydrinate may accumulate due to its high hepatic metabolism.- Patients suffering from [GLAUCOMA], [PROSTATIC HYPERPLASIA] or [URINARY BLADDER OBSTRUCTION], [ARTERIAL HYPERTENSION], [CARDIAC ARRHYTHMIA], [MYASTHENIA GRAVIS], stenosing [PEPTIC ULCER] or [INTESTINAL OBSTRUCTION]. Worsening may occur due to the anticholinergic effects of dimenhydrinate.- Diseases of the lower respiratory tract, such as [ASTHMA], [PULMONARY EMPHYSEMA] or [CHRONIC OBSTRUCTIVE PULMONARY DISEASE]. H1 antihistamines may thicken bronchial secretions due to their anticholinergic effects.- [EPILEPSY]. Antihistamines have occasionally been associated with paradoxical hyperexcitability reactions.- [APPENDICITIS]. Due to its antiemetic effects, it may delay the diagnosis of appendicitis.- Ototoxicity. Dimenhydrinate may improve vertigo, tinnitus, and motion sickness, and may therefore mask ototoxicity induced by ototoxic drugs.- Photosensitivity. Dimenhydrinate may cause photosensitivity, so it is recommended not to expose yourself to the sun during treatment and to protect yourself with sunscreen.- Extreme temperatures. It may aggravate heat stroke due to the decrease in sweating caused by its anticholinergic effects. It is recommended to avoid exposure to very high temperatures and to follow appropriate hygienic and dietary measures, such as adequate ventilation and hydration. Patient advice - This medicine should be administered with food or drinks. - It is advisable to administer dimenhydrinate at least half an hour before the trip, and to continue the doses throughout the trip if necessary, respecting the recommended dosage intervals. - It can cause drowsiness, so it is recommended to be cautious when driving, and not to combine it with drugs or other sedative substances such as alcohol. - Patients being treated with sedative drugs are not advised to self-medicate with products containing dimenhydrinate without consulting a doctor. - It is advisable not to sunbathe during treatment. - The doctor should be notified of any chronic pathology that the patient has before starting treatment. - Exposure to extreme temperatures should be avoided while using this medicine, keeping the patient in a cool environment and staying adequately hydrated. Special warnings - Dimenhydrinate could mask the effects ototoxic effects of some drugs, so it is recommended to periodically evaluate the acoustic function in patients treated with these drugs. - Before using this medicine in patients with vomiting of unknown origin, it is recommended to rule out the presence of appendicitis. - It is recommended to monitor the patient's hydration in the event of a heat wave, and especially if the patient is a young child, an elderly person, or a person with a serious illness. - Due to the antiallergic effects of this medicine, it may give false negatives in skin tests for hypersensitivity to antigenic extracts. It is recommended to discontinue administration of this medicine at least 72 hours before the test. Interactions Dimenhydrinate may mask the symptoms induced by ototoxic drugs by reducing vertigo or dizziness. Similarly, it may enhance the photosensitizing effects of other active ingredients that lead to photosensitivity reactions. Furthermore, due to its activity, it could enhance the effects of other sedative and anticholinergic drugs. Pregnancy The safety and efficacy of this medicine in pregnant women have not been evaluated. Its use is only recommended in the absence of safer therapeutic alternatives. Breastfeeding Dimenhydrinate is excreted in milk, so due to the risk of adverse reactions in infants, it is recommended not to use this medicine. Children Children are more sensitive to the side effects of H1 antihistamines. Caution is recommended. Elderly The elderly are more sensitive to the adverse effects of antihistamines. Caution is recommended. Effects on driving Dimenhydrinate may substantially affect the ability to drive and/or operate machinery, so extreme caution should be taken. Adverse reactions Side effects are usually mild and transient, especially at the beginning of treatment. - Digestive. [NAUSEA], [VOMITING], [DRY MOUTH], [CONSTIPATION]. - Cardiovascular. [TACHYCARDIA].- Neurological/psychological. [DROWSY] In young children and the elderly, [EXCITABILITY] may occur.- Ophthalmological. [BLURRED VISION] and [MYDRIASIS] may occur.- Allergic/dermatological. [HYPERSENSITIVITY REACTIONS], with [URTICARIA], [PRURITUS], [EXANTHEMATOUS ERUPTIONS]. [PHOTOSENSITIVITY REACTIONS] may occur.OverdoseDue to its wide therapeutic index, adverse reactions are only expected in the event of a significant ingestion of tablets. Nervous depression and anticholinergic symptoms may occur. Treatment should be symptomatic, together with the usual elimination measures (See Dimenhydrinate)