|Dosage and administration
Prevention and treatment of nausea, vomiting, dizziness caused by motion sickness: The tablet is taken at least 30 minutes before departure.
Adults and children over 12 years of age: 1 – 2 tablets once x 3 – 4 times a day. Maximum dosage should not exceed 8 tablets in a day.
Children: 6 – 12 years: ½ – 1 tablet once, every 6 to 8 hours as needed maximum dosage: 3 tablets/day.
Symptomatic treatment of Ménière’s disease: ½ – 1 tablet once x 3 times a day for maintenance treatment.
Note: Normal dose can be more sensitive to adverse effects in geriatric patients than in younger ones. Therefore, the lowest effective dose should be administered to elderly subjects.
Administration: Naturimine can be taken with food, milk to avoid stomach irritation.
Hypersensitivity to dimenhydrinate or other antihistamines.
Narrow angle glaucoma.
Urinary retention due to urethral-prostate disorders.
Children under 2 years.
|Warnings and precautions for use
Alcohol or other CNS depressants should be avoided because these drugs may increase hypnotic effects.
Because of the anti-cholinergic effect, dimenhydrinate should be used with caution in patients with chronic constipation (the risk of paralytic ileus), bladder-neck obstruction, aggravated prostatic hypertrophy.
Antiemetic effect of dimenhydrinate may impede diagnosis of appendicitis and may obscure signs of toxicity from overdosage of other drugs.
Dimenhydrinate may mask ototoxic symptoms, so caution should be exercised in patients who have used ototoxic medicines and they must be monitored closely if dimenhydrinate is used concomitantly.
Dimenhydrinate should be used with caution in elderly patients because orthostatic hypotension, dizziness and nausea easily occur in these patients.
Naturimine contains Sunset yellow which may cause allergic reactions. Caution should be exercised in patients with an atopic allergy to colorants.
|Recommendation for pregnancy and breastfeeding
There is no adequate study on dimenhydrinate use in pregnant women. Clinical studies in pregnant women have not indicated an increased risk of abnormalities when this drug is administered in any trimester of pregnancy. A fetal risk of adverse effects has not been demonstrated in animal studies. However, dimenhydrinate should only be used during pregnancy if it is really needed.
First-generation antihistamines may inhibit lactation because of their anticholinergic actions. A small amount of dimenhydrinate is distributed into breast milk. Thus, risk of adverse effects on fetus may occur. Therefore, a decision should be made whether to discontinue breastfeeding or to discontinue the drug, taking into account the importance of the drug to the mother.
|Effects on ability to drive and use machines
Dimenhydrinate causes drowsiness. Avoid driving or operating machine if you are taking this medicine.
|Interactions, incompatibilities of medicine
Dimenhydrinate may increase the effects of central nervous system depressants such as alcohol and barbiturates. Coadministration of dimenhydrinate and central nervous system depressants should be used with caution to avoid overdose.
Because dimenhydrinate has anticholinergic effects it increases the effects of anticholinergic drugs.
Dimenhydrinate may mask early symptoms of ototoxicity when it is concomitantly administered with aminoglycoside antibiotics or other ototoxic medicines.
|Undesirable effects (ADRs)
Drowsiness is the most common undesirable effect of dimenhydrinate. Some undesirable effects of dimenhydrinate are associated with its anticholinergic effect.
Common, ADR >1/100
Central nervous system: Somnolence, headache, vertigo, dizziness, incoordination.
Eyes: Blurred vision.
Dry mouth and respiratory tract.
Ears and labyrinth: Tinnitus.
Uncommon, 1/1000 < ADR < 1/100
Gastrointestinal: Anorexia, constipation or diarrhoea.
Urinary: Urinary retention, difficulty urinating.
Cardiovascular: Palpitations (fast heartbeat), hypotension.
Rarely, ADR < 1/1000
Central nervous system: Paradoxical stimulation in children, sometimes in adults: Agitation, tremor, insomnia, convulsions.
|Overdose and management
Overdose of dimenhydrinate usually occurs in children with symptoms similar to atropine overdose: Mydriasis, facial flushing, hyperpyrexia, agitation, hallucinations, confusion, incoordination, convulsions, coma, respiratory failure, cardiovascular collapse and possible death. Symptoms may be delayed up to 2 hours after drug administration, and death can occur within 18 hours.
In adults, doses up to 500 mg or larger can cause difficulty in talking and swallowing, psychosis that cannot be distinguished from atropine poisoning.
There are no specific antidotes for antihistamine overdose, the treatment is only symptomatic and supportive.
Reduction in absorption: Induction of emesis is usually ineffective. If there are no seizures, early gastric lavage may be applied to prevent inhalation of substances contained in the stomach. Keep the patient calm to minimize central nervous system irritation.
In case of seizures, treatment with diazepam in adults and phenobarbital in children should be used. Breathing machine (ventilator) can be required.
Dimenhydrinate is an antihistamine, sedative-hypnotic agent, belonging to the ethanolamine derivative group. It acts by competing with histamine for H1 receptor sites. Besides anti-histamine effect, dimenhydrinate also has anti-cholinergic, anti-vomiting and strong sedative effect.
Dimenhydrinate is primarily used as an antiemetic agent for the treatment of nausea, vomiting, and dizziness caused by motion sickness. The mechanism of these effects is not known exactly but may be related to the effect of dimenhydrinate which reduces vestibular stimulation and labyrinthine stimulation and function. Antiemetic effect may be due to an effect on the medullary chemoreceptor trigger zone.
Effect on inhibiting central nervous system usually decreases after a few days of treatment and antiemetic effect may be reduced somewhat after prolonged use.
Dimenhydrinate is well absorbed following oral administration, antiemetic effect occurs about 15 – 30 minutes following oral administration.
The duration of effect is usually 3 – 6 hours.
There is little information on the distribution and metabolism of dimenhydrinate. Like other antihistamines, dimenhydrinate can be widely distributed into the body tissues, and cross the placenta, a small amount is distributed into breast milk.
Dimenhydrinate is metabolized by the liver and excreted in the urine.
|Storage conditions, shelf-life, quality specification of the medicine
Storage conditions: Protect from humidity and light, below 30 degrees C.
Shelf – life: 36 months from the manufacture date.
Quality specification: In house specification.