Hydroxyzine-Associated Nightmares

Mechanism and Evidence

Hydroxyzine, a first-generation antihistamine, can alter sleep architecture and potentially trigger nightmares, particularly when used at bedtime, by affecting neurotransmitters including serotonin, norepinephrine, and dopamine, as well as those affecting GABA and acetylcholine 1
The American Academy of Sleep Medicine suggests that nightmares can be induced by drugs that affect these neurotransmitters, highlighting the potential risk of hydroxyzine 2

Bedtime dosing of hydroxyzine, often recommended for pruritus and sleep disturbances, can contribute to disturbed dreaming 3, 4
Higher doses of hydroxyzine, typically 10-25 mg QID or at bedtime, may increase the risk of nightmares 3, 4
Individual sensitivity to the central nervous system effects of antihistamines, such as hydroxyzine, can also play a role in the development of nightmares 1

Adjusting the timing of hydroxyzine administration, such as taking it earlier in the evening, may help minimize nightmares while maintaining therapeutic benefit 1
Dose reduction of hydroxyzine may also help minimize nightmares while maintaining therapeutic benefit 1
For patients requiring antihistamine therapy who experience nightmares with hydroxyzine, switching to a second-generation antihistamine with less central nervous system penetration for daytime use may be considered 1
Alternative sedative medications with different mechanisms of action may be considered if hydroxyzine is specifically needed for its sedative properties 2

Elderly patients should start with lower doses of hydroxyzine and be monitored closely due to increased sensitivity to psychomotor impairment and risk of falls 1
Hydroxyzine is contraindicated during early pregnancy, and dose should be halved in moderate renal impairment and avoided in severe renal impairment 1