Do second-generation antihistamines (e.g. loratadine, cetirizine) treat vertigo?

Second-Generation Antihistamines Are Not Effective for Treating Vertigo

Second-generation antihistamines (such as loratadine and cetirizine) are not effective for treating vertigo and are not recommended for this purpose. While first-generation antihistamines are sometimes used as vestibular suppressants for vertigo, second-generation antihistamines lack the central nervous system penetration and anticholinergic properties necessary for vestibular suppression 1.

Mechanism of Action and Vertigo Treatment

Second-generation antihistamines differ from first-generation antihistamines in several important ways:

• Limited CNS penetration: Second-generation antihistamines have limited ability to cross the blood-brain barrier 2
• Minimal anticholinergic effects: They lack the significant anticholinergic properties that contribute to vestibular suppression 2
• Different receptor activity: They primarily target peripheral H1 receptors without affecting the central vestibular system 3

First-Generation vs. Second-Generation Antihistamines

First-generation antihistamines (like diphenhydramine and meclizine) may be used for vertigo because:

• They readily cross the blood-brain barrier
• They have anticholinergic properties that suppress vestibular function
• They act centrally to reduce the sensation of motion 3

However, these same properties cause significant side effects:

• Sedation and drowsiness
• Impaired cognitive function
• Risk of falls, particularly in elderly patients 2, 1

Evidence-Based Approach to Vertigo Management

The appropriate treatment for vertigo depends on the underlying cause:

For Peripheral Vertigo (BPPV, Vestibular Neuritis, Ménière's):

1. First-line treatment for BPPV: Canalith repositioning procedures (CRPs) like the Epley maneuver (90.7% success rate) 1

   • Vestibular suppressants should NOT be used routinely for BPPV

2. For acute vestibular neuritis:

   • Brief use of vestibular suppressants (first-generation antihistamines) during acute phase only
   • Vestibular rehabilitation for long-term management 1

3. For Ménière's disease:

   • Salt restriction and diuretics for prevention
   • Vestibular suppressants during acute attacks 1, 3

For Central Vertigo (Migraine-Associated, Stroke):

1. Migraine-associated vertigo:

   • Prophylactic medications (calcium channel antagonists, tricyclic antidepressants, beta-blockers)
   • NOT antihistamines 1, 3

2. Stroke-related vertigo:

   • Management of underlying condition
   • Vestibular rehabilitation 1

Pharmacological Options for Acute Vertigo

When medication is needed for acute vertigo symptoms:

• First-generation antihistamines: May be used short-term for symptom relief
• Benzodiazepines: Can reduce anxiety associated with vertigo but may delay vestibular compensation
• Antiemetics: Prokinetic antiemetics like metoclopramide may help with nausea without significantly interfering with vestibular compensation 1, 4

Important Clinical Considerations

• Recent evidence suggests single-dose antihistamines (first-generation) provide greater vertigo relief at 2 hours than benzodiazepines 4
• Long-term use of vestibular suppressants may delay vestibular compensation 3, 5
• Elderly patients are particularly vulnerable to anticholinergic effects and require lower medication doses 1
• Vestibular rehabilitation exercises are beneficial, especially when medications fail 1

Conclusion

Second-generation antihistamines like loratadine and cetirizine lack the central nervous system effects needed to treat vertigo and should not be used for this purpose. Treatment should be directed at the underlying cause of vertigo, with appropriate use of first-generation antihistamines only when vestibular suppression is specifically indicated.