Meclizine

BRAND NAMES:

Antivert: This tablet works as an antihistaminic; it makes you drowsy by inhibiting the effects of histamine, a neurotransmitter that regulates nausea, vomiting, and balance. The drug is available in 25 mg, 32 mg, 50 mg, and 100 mg.

Mecliv B6: Each uncoated tablet contains meclizine 25 mg. Vitamin B6 (pyridoxine) is used to treat motion sickness and vertigo. It stops the feeling of queasy, throwing up, dizziness, and other vertigo symptoms.

MECHANISM OF ACTIONS:

Meclizine is a first-generation antihistamine (non-selective H1 receptor antagonist). The medication also has central anticholinergic properties. Meclizine's antiemetic and antivertigo qualities are due to its ability to inhibit these receptors. This inhibiting action takes place in the medulla's vomiting center and chemoreceptor trigger zone. These effects decrease histamine neurotransmission from the solitary tract nucleus and the vestibular nuclei to the chemoreceptor trigger zone and vomiting center in the medulla. This action also lowers vestibular activation and labyrinth excitability.

PHARMACOKINETICS:

Absorption: Meclizine is absorbed upon oral administration. The medication reaches peak plasma levels around three hours after dosing. The activity begins around one hour after oral ingestion.

Distribution: The volume of distribution of meclizine is 6.78 ± 3.52 L. The blood-brain barrier is crossed by meclizine.

Metabolism: Although there is insufficient evidence on meclizine metabolism, in vitro metabolic investigations have revealed that the major hepatic enzyme that metabolizes meclizine is CYP2D6.

Elimination: The medicine is eliminated as a metabolite in urine and unaltered in feces. The half-life of meclizine is roughly 6 hours, and its activity lasts between 8 and 24 hours.

DOSAGE AND ADMINISTRATION

Meclizine is administered as chewable or non-chewable oral tablets. The dosage for oral tablets ranges from 25 to 50 mg. Chewable tablets are available in 25 mg doses. Chewable tablets must be broken or thoroughly chewed before ingesting. The medicine can be taken without consideration for food.

Motion sickness: To prevent motion sickness, the suggested dosage is 25 to 50 mg orally, taken one hour before embarking. Additional dosages may be administered once every 24 hours as needed.

Vertigo: For vestibular illnesses, the recommended daily oral dose ranges from 25 to 100 mg. Subsequent dosages should be modified based on the patient's clinical response.

Meniere disease: The suggested dose of meclizine is 12.5 to 25 mg every 8 hours.

CONTRAINDICATIONS:

People having a history of hypersensitivity to the medicine or its excipients, such as tartrazine, should not take meclizine. Tartrazine-containing formulations can cause allergic responses.

DRUG INTERACTIONS:

Because of its anticholinergic and CNS depressive qualities, meclizine may interact with a wide range of drugs, particularly those with anticholinergic and sedative effects. Patients should avoid alcohol, tranquilizers, and sedatives when using meclizine since they increase the risk of central nervous system depression.

Meclizine's metabolism via CYP2D6 makes it susceptible to pharmacological interactions with CYP2D6 inhibitors. Consequently, doctors must constantly monitor for adverse events and examine the clinical outcomes when meclizine is co-administered with CYP2D6 inhibitors. Anticholinergic medicines or pharmaceuticals with anticholinergic qualities combined with meclizine may enhance anticholinergic effects.

SIDE EFFECTS:

Meclizine's common side effects include

• Dizziness
• Fast heartbeat
• Difficulty swallowing
• Tightness in chest
• Vomiting
• usually weakness and tiredness
• Itching
• skin rash
• Drowsiness
• Cough
• Swelling of the eyelids or around the eyes, face, or lips

Meclizine's serious side effects include

• Dizziness
• Fast heartbeat
• Difficulty swallowing
• Tightness in chest
• Vomiting
• Usually weakness and tiredness
• Itching, skin rash
• Drowsiness
• Cough
• Swelling of the eyelids or around the eyes, face, or lips

TOXICITY:

There are no particular antidotes for meclizine overdose. The primary goal of treatment is to alleviate symptoms. Overdose symptoms may include CNS depression, such as sleepiness, convulsions, or coma. Although hypotension is possible, it is more common in the elderly. An overdose in children can cause anticholinergic effects and CNS stimulation, resulting in hallucinations, convulsions, and sleeplessness. To avoid additional drug absorption after recent administration, induce emesis or undergo stomach lavage. Activated charcoal is also an alternative. Meclizine has no known antidote, but physostigmine can help to counteract its systemic anticholinergic effects.

STORAGE CONDITIONS:

Keep the container at room temperature. Keep the container completely covered. After the expiration date, discard any medication that is not in use.