Cinfamar 50 Mg 10 Film-coated Tablets

Cinfamar (50 Mg 10 Coated Tablets)

Dimenhydrinate

ACTION AND MECHANISM

- [ANTIALLERGIC], [HISTAMINERGIC ANTAGONIST (H-1)]. Dimenhydrinate is an equimolecular complex of diphenhydramine and a derivative of theophylline, 7-chloro-theophylline. Diphenhydramine is a derivative of ethanolamine, which competitively, reversibly and nonspecifically blocks H1 receptors, reducing the systemic effects of histamine. It leads to vasoconstriction and decreased vascular permeability, reducing redness and edema associated with allergy. Partially mitigates symptoms associated with allergic processes such as eye redness or nasal congestion. It also produces a slight bronchodilator effect and a decrease in dermal itching.
Dimenhydrinate is a nonspecific H1 antagonist, so it is capable of antagonizing other receptors such as central and peripheral cholinergic receptors. By crossing the blood-brain barrier and blocking H1 and muscarinic receptors, it will lead to sedation, but lighter than ethanolamines.
- [MUSCARINIC CHOLINERGIC ANTAGONIST (M)], antiemetic. Dimenhydrinate is a nonspecific antagonist capable of also blocking other receptors such as central or peripheral muscarinic receptors. The blockade of the central H1 and cholinergic receptors could exert an antiemetic effect, although it has not been fully clarified. It has been found that this drug is capable of inhibiting vestibular stimulation, first inhibiting the stimuli formed in the otolic system, and at higher doses, in the semicircular canals. After continued use, a tolerance to antiemetic effects has been noted.

PHARMACOKINETICS

- Absorption: Dimenhydrinate is well absorbed from the intestine, but suffers an intense hepatic first pass effect. After the administration of a dose, the effects appear after 15-30 minutes, and their duration is 3-6 hours. The Tmax is 2 hours.

- Distribution: Dimenhydrinate is widely distributed throughout the body, crossing the blood-brain and placental barriers. It is also excreted in small amounts with milk.

- Metabolism: It is metabolized quickly and almost completely in the liver.

- Elimination: The metabolites are eliminated with the urine.

INDICATIONS

- Prevention and treatment of [NAUSEAS], [VOMITING] and [VERTIGO] associated with [KINETOSIS].

POSOLOGY

- Adults and adolescents over 12 years: 50-100 mg / 4-6 h. Maximum dose 400 mg / 24 h.
- Children 7-12 years: 25-50 mg / 6-8 h. Maximum dose 150 mg / 24 h.
- Children 2-6 years: 12.5-25 mg / 6-8 h. Maximum dose 75 mg / 24 h.
- Children under 2 years of age: safety and efficacy have not been evaluated.
Administer at least 30 min before the trip, and preferably 1-2 h before.

RULES FOR CORRECT ADMINISTRATION

Administration with food : administer together with food, water or milk to reduce gastric discomfort.
- Tablets: swallow the tablets whole or broken down into juice or sugary drinks.

CONTRAINDICATIONS

- Hypersensitivity to any component of the drug. There may be cross reactions with other antihistamines, so it is not recommended to use any H1 antihistamine in patients who have presented hypersensitivity to any compound in the group.
- [ASTHMA CRISIS]. For some authors, dimenhydrinate could worsen asthma, so its use in an acute attack is not recommended.
- [PORFIRIA]. H1 antihistamines have been associated with the appearance of porphyric outbreaks and are therefore not considered safe in these patients.

PRECAUTIONS

- [RENAL INSUFFICIENCY]. The safety and efficacy have not been evaluated in patients with renal impairment, but the metabolites of dimenhydrinate are excreted in the urine, therefore accumulation of the same may occur. Since these metabolites could be active, it could be necessary to prolong the administration periods in patients with renal insufficiency, especially in moderate or severe conditions (CLcr less than 60 ml / minute).
- [LIVER FAILURE]. Dimenhydrinate is extensively metabolized by hepatic metabolism. In the event of liver failure, an increase in plasma concentration could occur, with the consequent risk of adverse effects. A dosage adjustment may be necessary in these patients depending on the degree of liver function.
- Patients suffering from [GLAUCOMA], [PROSTATIC HYPERPLASIA] or [URINARY BLADDER OBSTRUCTION], [ARTERIAL HYPERTENSION], [CARDIAC ARRHYTHMIA], [GRAVE MYASTENIA], [PEPTIC ULCER] stenosing or [INTESTINAL OBSTRUCTION]. Due to the anticholinergic effects of dimenhydrinate, these conditions may worsen, so it is recommended to exercise extreme caution and suspend treatment in the event of a worsening.
- Diseases of the lower respiratory tree, such as [ASTHMA], [PULMONARY EMPHYSEMA] or [CHRONIC OBSTRUCTIVE PULMONARY DISEASE]. According to some authors, H1 antihistamines could decrease the volume of bronchial secretions, increasing their viscosity, due to their anticholinergic effects, which could aggravate these conditions. However, there is not much clinical evidence, despite which, extreme caution is recommended in these patients. As a general rule, its use is not recommended in patients with asthmatic attacks (See Contraindications).
- [EPILEPSY]. Caution should be exercised in epileptic patients, since antihistamines have occasionally been associated with paradoxical hyperexcitability reactions, even at therapeutic doses, and therefore could lower the seizure threshold.
- [APENDICITIS]. Due to its antiemetic effects, it could interfere with the diagnosis of appendicitis. It is recommended to previously rule out the presence of appendicitis in patients with vomiting of unknown origin.
- Ototoxicity. Dimenhydrinate can exert a beneficial effect in case of vertigo, tinnitus and dizziness, so it could mask the ototoxicity induced by ototoxic drugs such as parenteral aminoglycosides, carboplatin, cisplatin, chloroquine and erythromycin among others.
- Photosensitivity. Dimenhydrinate could give rise to photosensitivity phenomena, so it is recommended not to sunbathe during treatment, and protect yourself with sun filters.
- Extreme temperatures. H1 antihistamines may aggravate exhaustion-dehydration syndrome and heat stroke due to decreased sweating caused by their anticholinergic effects. Those patients being treated with these drugs are recommended to avoid exposure to very high temperatures, especially in the case of young children, the elderly or people with serious chronic diseases. It is also advisable to follow adequate hygienic-dietary measures, such as adequate aeration and hydration.

ADVICE TO THE PATIENT

- Administer when symptoms appear, along with food to reduce gastric discomfort. In sensitive people, it could be administered 1-2 h before the trip.
- The administration may be repeated during the trip, as long as the intervals between doses are respected and the maximum recommended dose is not exceeded.
- It can cause drowsiness, so it is recommended to exercise caution when driving, and not to combine it with drugs or other sedative substances such as alcohol.
- Patients on sedative drugs are not advised to self-medicate with dimenhydrinate products without consulting a physician.
- It is advisable not to sunbathe during the treatment.
- Any chronic pathology that the patient presents should be notified to the doctor before starting treatment.
- Exposure to extreme temperatures should be avoided during the use of this medicine, keeping in a cool environment, hydrating properly.

SPECIAL WARNINGS

- Dimenhydrinate could mask the ototoxic effects of some drugs, so it is recommended to periodically evaluate acoustic functionality 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 small child, an elderly person or a person with a serious illness.
- Due to the antiallergic effects of this medicine, it could give false negatives in dermal tests of hypersensitivity to antigenic extracts. It is recommended to suspend the administration of this medicine at least 72 hours before the test.

INTERACTIONS

Dimenhydrinate may mask ototoxic drug-induced symptoms by reducing vertigo or dizziness. Similarly, it could enhance the photosensitizing effects of other active ingredients that give rise to photosensitivity reactions. In addition, drug interactions with the following active principles have been described:
- Ethyl alcohol. The joint administration of alcohol and dimenhydrinate could enhance the sedative effects of both substances. It is recommended to avoid alcohol consumption during treatment.
- Anticholinergics (antiparkinsonians, tricyclic antidepressants, MAOIs, neuroleptics). The administration of dimenhydrinate together with other anticholinergic drugs could potentiate the anticholinergic effects, so it is recommended to avoid the association.
- Sedatives (opioid analgesics, barbiturates, benzodiazepines, antipsychotics). Co-administration of dimenhydrinate with a sedative drug could enhance the hypnotic action. It is recommended to extreme precautions.

PREGNANCY

FDA Category B. In studies carried out in rats and rabbits using doses 20-25 times higher than human ones, they have not shown harm to the fetus. There have been no adequate and well-controlled studies in humans. However, dimenhydrinate has been used in hyperemesis gravidarum without significant adverse effects. However, there are reports of a possible association between administration during the last two weeks of pregnancy and the appearance of retrolental fibroplasia in premature infants. Although the possibility of harm to the fetus seems remote, this medicine should only be used when the benefits outweigh the possible risks.

LACTATION

Dimenhydrinate could inhibit lactation due to its anticholinergic effects. It is also excreted with breast milk in small amounts, although it is unknown if these could have effects on the infant. However, children are more sensitive to anticholinergic reactions, and may present with paradoxical hyperexcitability reactions more frequently. It is recommended to stop breastfeeding or avoid the administration of this medicine.

KIDS

The use of dimenhydrinate is not recommended in children under two years of age, especially neonates and infants, because they may be more susceptible to anticholinergic adverse effects. In children older than 2 years, cases of paradoxical reactions with hyperexcitability have been described, especially at high doses, so it is recommended to use it with caution.

SENIORS

The elderly are more sensitive to the adverse effects of antihistamines, such as dizziness, sedation, confusion, hypotension and hyperexcitability, as well as anticholinergic effects (dry mouth, urinary retention, glaucoma precipitation). Antihistamines can be used in patients over 65 years of age, but caution should be exercised. If the side effects persist or are severe, it is advisable to stop the treatment.

EFFECTS ON DRIVING

Dimenhydrinate can substantially affect the ability to drive and / or operate machinery. Patients should avoid operating dangerous machinery, including automobiles, until they are reasonably certain that drug treatment does not adversely affect them.

ADVERSE REACTIONS

The side effects of dimenhydrinate are usually mild and transient, being more frequent during the first days of treatment. Like other ethanolamines, dimenhydrinate mainly causes drowsiness and anticholinergic phenomena, but there is great interindividual variability with respect to the frequency and intensity of symptoms, affecting mainly young children and the elderly. The most common adverse reactions are:
- Digestive. [NAUSEA], [VOMITING], [CONSTIPATION], [DIARRHEA], [EPIGASTRIC PAIN], [ANOREXIA], [DRY MOUTH]. These symptoms can be lessened by giving the antihistamine with food.
- Neurological / psychological. [Drowsiness] is common (1-9%), especially at the beginning of treatment, and usually decreases after 2-3 days. [HEADACHE], [VERTIGO] and [DIZZINESS] have also been described. Exceptionally, cases of paradoxical [EXCITABILITY] have been observed, especially in young children. This hyperexcitability occurs with [INSOMNIA], [NERVIOSISM], [CONFUSION], [TREMOR], [IRRITABILITY], [EUPHORIA], [DELUSION], palpitations and even [SEIZURES].
- Cardiovascular. Occasionally, and usually in case of overdose, [TACHYCARDIA], [PALPITATIONS] and others [CARDIAC ARRHYTHMIA] such as [EXTRASISTOLE] or [CARDIAC BLOCK] can occur. These effects could be due to anticholinergic activity. [HYPOTENSION] or [ARTERIAL HYPERTENSION] have occasionally been described.
- Respiratory. Sometimes there can be an increase in the viscosity of bronchial secretions, which can make breathing difficult.
- Genitourinary. [URINARY RETENTION] and [SEXUAL IMPOTENCE] may appear due to cholinergic blockade.
- Hematological. [HEMOLYTIC ANEMIA], [AGRANULOCYTOSIS], [LEUCOPENIA], [THROMBOCYTOPENIA] or [PANCYTOPENIA] have been rarely described.
- Eyepieces. Due to the anticholinergic activity a [GLAUCOMA] and [VISION DISORDERS] such as [MIDRIASIS], [BLURRED VISION] or [DIPLOPIA] could occur.
- Allergic / dermatological. [HYPERSENSITIVITY REACTIONS] may appear after systemic administration of antihistamines, which can even produce [ANAPHYLAXY]. [PHOTOSENSITIVITY REACTIONS] may also appear after intense exposure to sunlight, with [DERMATITIS], [PRURITO], [EXANTEMATIC ERUPTIONS] and [ERYTHEMA].

OVERDOSE

Symptoms: Symptoms usually appear after 2 hours, although they can last for 18 hours, and are usually variable, presenting greater severity in children and over 65 years. Moderate nervous depression, with sedation and apnea, cardiovascular collapse, hyperexcitability with insomnia, hallucinations, tremors or seizures, and anticholinergic symptoms such as dry mouth, blurred vision, and urinary retention have been described. A fever higher than 41.8 ºC may also appear.
In the most severe cases, especially in children, symptoms may worsen, including hypotension, seizures, respiratory depression, loss of consciousness, coma, and death.
Treatment: The treatment will consist of the usual measures designed to favor the elimination of the drug. Administration of emetics is often ineffective. Although a gastric lavage may be beneficial if less than 3 hours have elapsed since ingestion.
The patient will be kept calm to minimize stimulation of the central nervous system. Seizures can be treated with diazepam in adults and phenobarbital in children at doses of 5-6 mg / kg. Hypotension can be treated with vasopressors, although epinephrine should be avoided as it can further lower pressure.
If necessary, intubation and assisted breathing may be used. The use of analeptics is not recommended as they could induce seizures.

Cinfamar 50 Mg 10 Coated Tablets Leaflet