Action and mechanism

- [ANTIEMETIC], [HISTAMINERGIC (H-1) ANTAGONIST], [MUSCARIANINIC (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 SICKNESS]. Treatment of [NAUSEA] and [VOMITING] associated with [MOTION SICKNESS] during travel.

- [VERTIGO].

Posology

Dosage:

- Adults, oral: 1-2 tablets before travel. This dose should be repeated every 3-4 hours throughout 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 have not been evaluated in children.

Rules for correct administration

The tablets can be swallowed whole or dissolved in any juice or sugary drink. To do this, crush the tablet into the glass with a teaspoon, add a little liquid, shake, and then top up to the desired volume.
It is recommended to take this medication preferably 1-2 hours before travel, and if not possible, at least 30 minutes beforehand. Doses should be repeated every 3-4 hours if necessary throughout the duration of the trip, respecting the recommended intervals.

Contraindications

- Hypersensitivity to any component of the medication, including [XANTHINE ALLERGY].

- [ASTHMA ATTACK].

- [PORPHYRIA]. H1 antihistamines have been associated with the occurrence of porphyric flares.

Precautions

- [KIDNEY FAILURE]. Accumulation of dimenhydrinate may occur because it and its metabolites are eliminated in 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.

- Lower respiratory tract diseases, such as [ASTHMA], [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 to avoid sunbathing during treatment and to protect yourself with sunscreen.

- Extreme temperatures. May worsen heat stroke due to the decreased sweating caused by its anticholinergic effects. It is recommended to avoid exposure to very high temperatures and follow appropriate hygiene and dietary measures, such as adequate ventilation and hydration.

Patient Advice

- This medicine will be administered with food or drink.

- It is advisable to administer dimenhydrinate at least half an hour before the trip, and 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 medications or other sedative substances such as alcohol.

- Patients receiving sedative drugs are not advised to self-medicate with dimenhydrinate products without consulting a physician.

- It is advisable not to sunbathe during treatment.

- The doctor must be notified of any chronic pathology the patient has before starting treatment.

- Exposure to extreme temperatures should be avoided while using this medication, by staying in a cool environment and staying adequately hydrated.

Special warnings

- Dimenhydrinate may mask the ototoxic effects of some drugs, so it is recommended to periodically evaluate 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 during a heat wave, especially if the patient is a young child, an elderly person, or someone with a serious illness.

- Due to the anti-allergic effects of this medication, it may cause false negative results in skin hypersensitivity tests to antigenic extracts. It is recommended that you discontinue taking this medication at least 72 hours before the test.

Interactions

Dimenhydrinate may mask symptoms induced by ototoxic drugs by reducing vertigo or dizziness. It may also enhance the photosensitizing effects of other active ingredients that cause photosensitivity reactions. Furthermore, due to its activity, it may enhance the effects of other sedative and anticholinergic drugs.

Pregnancy

The safety and efficacy of this medication in pregnant women have not been evaluated. Its use is only recommended if safer therapeutic alternatives are unavailable.

Lactation

Dimenhydrinate is excreted in milk, so due to the risk of adverse reactions in the infant, it is recommended not to use this medication.

Children

Children are more sensitive to the side effects of H1-antihistamines. Caution is advised.

Seniors

Elderly people are more sensitive to the adverse effects of antihistamines. Caution is advised.

Effects on driving

Dimenhydrinate may substantially impair the ability to drive and/or operate machinery, so extreme caution should be exercised.

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. [DROWSINESS]. [EXCITABILITY] may occur in young children and the elderly.

- Ophthalmological. [BLURRED VISION] and [MYDRIASIS] may occur.

- Allergic/dermatological. [HYPERSENSITIVITY REACTIONS], with [URTICARIA], [PRURITUS], [EXANTHEMATOUS ERUPTIONS]. [PHOTOSENSITIVITY REACTIONS] may occur.

Overdose

Due to its broad therapeutic index, adverse reactions are only expected in the case of a significant intake of tablets. Nervous depression and anticholinergic symptoms may occur. Treatment should be symptomatic, along with standard elimination measures (See Dimenhydrinate).