Zyrtec-D is an over-the-counter medication formulated to relieve various allergy symptoms. This combination product contains two active ingredients: cetirizine hydrochloride and pseudoephedrine hydrochloride. It targets common allergy complaints such as sneezing, runny nose, and nasal congestion, helping individuals manage seasonal or year-round allergic rhinitis.
Does Zyrtec-D Cause Drowsiness?
The cetirizine component of Zyrtec-D, a second-generation antihistamine, is often described as “less drowsy” compared to older antihistamines. Despite this, about 1 in 10 people may still experience some level of drowsiness or fatigue from cetirizine.
The “D” in Zyrtec-D refers to pseudoephedrine, a decongestant that acts as a stimulant. While some individuals may feel sleepy, others might experience increased alertness, nervousness, or even trouble sleeping due to the pseudoephedrine. Individual reactions to Zyrtec-D can vary significantly, so it is important to observe how your body responds to the medication.
How Zyrtec-D’s Ingredients Affect Alertness
Cetirizine, an antihistamine, primarily works by blocking histamine H1 receptors, which are involved in allergic reactions. Unlike first-generation antihistamines, cetirizine crosses the blood-brain barrier only minimally, which reduces its likelihood of causing significant sedation. However, because histamine also plays a role in regulating sleep-wake cycles, blocking it can still induce mild drowsiness in some individuals.
The other active ingredient, pseudoephedrine, is a sympathomimetic amine that functions as a decongestant and a stimulant. It primarily stimulates alpha-adrenergic receptors, leading to the constriction of blood vessels in the nasal passages, which reduces swelling and congestion. This stimulation can also lead to systemic effects, including increased heart rate, elevated blood pressure, and central nervous system stimulation, which manifests as increased alertness, nervousness, or sleeplessness. These stimulant properties often offset the sedative effects of cetirizine, resulting in a net effect of alertness or wakefulness for many users.
Managing Drowsiness and Other Side Effects
Individuals who experience drowsiness from Zyrtec-D can try taking the medication in the evening to minimize daytime effects. If the medication causes trouble sleeping, taking it in the morning might be more suitable. Avoid activities requiring mental alertness, such as driving or operating heavy machinery, until you understand how Zyrtec-D affects you.
Avoiding alcohol or other sedatives while taking Zyrtec-D can intensify any potential drowsiness. Beyond drowsiness, other common side effects include dry mouth, dizziness, headache, and nervousness. Chewing sugarless gum or sipping water can help alleviate dry mouth. If drowsiness is severe or persistent, or if other side effects become bothersome, consulting a healthcare professional is recommended.