From the Guidelines
Meclizine can cause significant adverse effects, particularly in elderly patients, due to its anticholinergic properties and sedating effects, which may impair daily activities and increase the risk of falls, confusion, and delirium 1. Meclizine is an antihistamine medication that blocks histamine H1 receptors and has anticholinergic properties, which can affect various body systems. Common side effects of meclizine include:
- Drowsiness
- Dry mouth
- Blurred vision
- Fatigue Less common but more concerning side effects may include:
- Confusion
- Hallucinations
- Difficulty urinating
- Rapid heartbeat, particularly in elderly patients Meclizine can also cause significant sedation, which may impair driving ability and operation of machinery, so patients should avoid these activities until they know how the medication affects them 1. The medication may interact with alcohol and other central nervous system depressants, potentially increasing sedation. Patients with glaucoma, prostate enlargement, or certain heart conditions should use meclizine with caution. The typical dosage for motion sickness is 25-50 mg taken 1 hour before travel, while for vertigo, the usual dose is 25-100 mg daily divided into smaller doses. If side effects become severe or persistent, patients should contact their healthcare provider immediately. It is essential to consider the potential risks and benefits of meclizine, particularly in older adults, and to monitor patients closely for adverse effects, as anticholinergic medications like meclizine can have a significant impact on cognition, functional status, and activities of daily living (ADL) scores in older patients 1.
From the FDA Drug Label
Adverse Reactions: Advise patients that meclizine hydrochloride tablets may cause anaphylactic reaction, drowsiness, dry mouth, headache, fatigue, vomiting and, on rare occasions, blurred vision
- Adverse drug effects of meclizine include:
- Anaphylactic reaction
- Drowsiness
- Dry mouth
- Headache
- Fatigue
- Vomiting
- Blurred vision (rare occasions) 2
From the Research
Meclizine Adverse Drug Effects
- Meclizine is an antihistamine commonly used to treat vertigo and dizziness, but it can have adverse effects, including increased sleepiness 3.
- A study found that meclizine decreased the accuracy on the Sternberg working memory task, suggesting an effect on short-term memory, and reported side effects included increased sleepiness 3.
- Another study found that vestibular suppressants, including meclizine, were associated with an increased risk of falls in older adults, with a hazard ratio of 3.33 4.
- Meclizine has also been found to have cognitive side effects, including impaired working memory and attention 3.
- The use of meclizine and other vestibular suppressants is not recommended for routine treatment of dizziness in older adults due to the risk of falls and other adverse effects 4, 5.
Comparison with Other Medications
- A systematic review and meta-analysis found that single-dose antihistamines, including meclizine, provided greater vertigo relief at 2 hours than single-dose benzodiazepines 6.
- However, the review also found that daily antihistamine use may not benefit patients with acute vertigo, and that benzodiazepines were not associated with improvement in any outcomes for acute vertigo 6.
- A study comparing meclizine with diazepam found no difference in the treatment of acute peripheral vertigo, with both medications providing similar improvements in vertigo symptoms 7.
Special Considerations
- Meclizine should be used with caution in older adults due to the risk of falls and other adverse effects 4.
- Patients with a history of cognitive impairment or dementia should be monitored closely when taking meclizine due to its potential cognitive side effects 3.
- Meclizine may interact with other medications, including sedatives and antidepressants, and patients should be advised to report any changes in their medication regimen 5.