Meclizine is an antihistamine medication primarily used to prevent and treat symptoms of nausea, vomiting, and dizziness. It is available for purchase over-the-counter for managing motion sickness, but a prescription may be required for other conditions. This medication is a first-generation antihistamine, a class of drugs known for their sedative effects. It is sold under various brand names and comes in different oral forms.
Primary Uses of Meclizine
Meclizine is frequently used to prevent the symptoms associated with motion sickness. People who are prone to feeling nauseous or dizzy during travel by car, boat, or airplane can take the medication beforehand to lessen these effects. It is effective in inhibiting the queasiness and vomiting that can arise from the conflicting signals the brain receives about movement during travel.
The medication is also prescribed to manage vertigo, which is the sensation of spinning or dizziness even when a person is still. This symptom is often linked to problems within the inner ear’s vestibular system, which is responsible for balance. Conditions such as benign paroxysmal positional vertigo (BPPV) and Meniere’s disease can cause debilitating vertigo. Meclizine helps to control the dizziness associated with these vestibular disorders.
Mechanism of Action
Meclizine functions as an antihistamine with anticholinergic properties, meaning it blocks the action of both histamine and acetylcholine, two neurotransmitters in the brain. The drug specifically targets H1 receptors, which are involved in the body’s response to allergens and motion. By blocking these receptors, it interrupts the communication pathways that lead to feelings of sickness.
The medication works by inhibiting signals that originate from the vestibular system in the inner ear. This system detects motion and sends information to the brain. When these signals are excessive or conflict with what the eyes are seeing, nausea and dizziness can occur. Meclizine acts on brain regions, including the chemoreceptor trigger zone, to stop these signals from being processed, effectively preventing the sensations of nausea and vomiting.
Dosage and Administration Guidelines
The appropriate dosage of meclizine depends on the condition it is being used to treat. For the prevention of motion sickness in adults, a dose of 25 to 50 milligrams is taken one hour before travel begins. This dose can be repeated every 24 hours as needed throughout the duration of travel.
When used to manage vertigo, the dosage may be different and is determined by a healthcare provider. A doctor might prescribe 25 to 100 milligrams per day, divided into several doses. Meclizine is available in several forms, including standard and chewable tablets. Common brand names include Bonine, Dramamine Less Drowsy, and the prescription medication Antivert.
The effects of the medication last for a significant period, so doses are spaced out. For children under 12, the use and dosage must be determined by a doctor, as safety and efficacy have not been established for this age group in some formulations.
Side Effects and Precautions
The most common side effects associated with meclizine are drowsiness and dry mouth. Some individuals may also experience fatigue or blurred vision. These effects are generally mild, but the drowsiness can impact a person’s ability to drive or operate machinery safely.
Less common, but more serious, side effects can occur, although they are rare. These can include allergic reactions characterized by a rash, itching, or swelling, as well as severe dizziness or difficulty breathing. If any of these serious reactions happen, it is important to seek medical attention immediately.
Precautions
The elderly may be more susceptible to its side effects. People with specific medical conditions, such as asthma, glaucoma, or an enlarged prostate, should consult a doctor before using this medication, as it may worsen these conditions.
Combining meclizine with alcohol or other central nervous system depressants, like sedatives or some pain medications, can increase drowsiness and should be avoided. Women who are pregnant or breastfeeding should also speak with a healthcare provider before taking meclizine.