Zyrtec and Alcohol


What is the use of Zyrtec

Zyrtec is a Brand name for an antihistamine drug that contains cetirizine as an active ingredient. This second-generation antihistamine is used for relieving the symptoms such as: coomon cold or allergy symptoms such as itching, sneezing, or runny nose or watery eyes.


Zyrtec indications are: allergies, hay fever, urticaria and angioedema. As a second-generation antihistamine, cetirizine is less able to pass the blood-brain barrier, thus it has less effects on the CNS compared to first-generation antihistamines such as diphenhydramine, chlorpheniramine and carbinoxamine.

These drugs are more likely to cause drowsiness or to interfere with memory formation because they can pass the blood-brain barrier. Zyrtec does not have anticholinergic side effects.

How Zyrtec works in the body

Chemically cetirizine is the active metabolite of hydroxyzine, the piperazine H1-receptor antagonist. Cetirizine competes with natural, body histamine for binding places at H1-receptor at the effector cell surface, which results in suppression of histaminic edema, pruritus and flare.


The lower incidence of causing sedation can be linked with lower cetirizine penetration into the CNS as a result of the less lipophilic carboxyl functional group on the ethylamine side chain.

Cetirizine can also inhibit eosinophil chemotaxis and leukotrienes release. Studies have been found that cetirizine can inhibit the expression of VCAM-1 in patients with atopic dermatitis.

How alcohol works in the human body

Pharmacologically alcohol affects the CNS, Hormones, Liver, Gastrointestinal, Cardiovascular system, Kidney and Metabolism. In Central Nervous System alcohol causes both, inhibition and stimulation in different ways. Inhibition is caused by potentiating the specific subunits of the GABA receptor, which activates the protein kinase C and causes sedation.

In addition, alcohol inhibits the release of excitatory neurotransmitters such as glutamate and acetylcholine. Stimulatory effects are caused after D2 – Dopamine receptors stimulation causing the release of endorphins and resulting in Euphoria.

Larger alcohol amounts may cause vasodilatation, increased Blood pressure, and alcoholic cardiomyopathy. In liver, alcohol causes fatty changes which are reversible, and caused by lipid metabolism impairment and mobilization of peripheral fat.

Prolonged alcohol administration can cause damage of liver tissue leading to diffuse fibrous scar formation resulting in Cirrhosis. Alcohol causes diuresis through the inhibition of Antidiuretic Hormone – ADH secretion.

Alcohol can decrease the production of testosterone resulting in impotence. Labor is inhibited through lowering oxytocin secretion. Acute presence of alcohol in blood will inhibit the oxidation of drugs by saturation of cytochrome P450, promoting the effects of these drugs.

CYP 450 Oxidation of many classes of drugs can be inhibited if alcohol is present; these include: Opioids, psychotropic drugs, Hypnotics, vasodilators, anticoagulants, analgesics, antidiabetics, anticonvulsants and antibiotics.

However, chronic consumption of alcohol induces the CYP450 drug-metabolizing system, increasing the oxidation of drugs in sober or abstinent alcoholics and lowering the effects of the drugs administrated at the same time.

What problems can cause alcohol when it is mixed with prescription or OTC medication?

Alcohol may have dangerous and harmful interactions when it is taken together with prescription or over-the-counter drugs, and in some rare cases even herbal remedies.

Alcohol interactions with drugs may cause side effects such as: headache, nausea and vomiting, dizziness, fainting, drowsiness, blood pressure changes, loss of motor coordination, abnormal behavior and accidents.

Combining alcohol and medications may also increase the risk of following complications: heart problems, liver damage and cirrhosis, internal bleeding, depression and impaired breathing.

Alcohol interactions may also decrease the effectiveness of medications used together or render them useless. Alcohol interactions with different drugs may make drugs harmful or even toxic to the body.

Even when it is used in small amounts, alcohol  may intensify drug side effects such as drowsiness,  sleepiness, and light-headedness, that may interfere with patients memory, concentration and ability to operate machinery or drive a car. All these side effects may lead to serious or even fatal accidents.

Can Patients take Zyrtec with Alcohol?

Although it is not expected that combination of Zyrtec and alcohol can cause serious side effects, patients using this anti-allergy should be advised to avoid consuming alcoholic while taking Zyrtec (cetirizine).

As a second generation antihistamine, Zyrtec is less expected to pass into CNS, which means that it is less able to cause CNS side effects such as sedation, while Alcohol is a central nervous system depressant, frequently associated with sedation.

However, combination of these two substances may lead to increased CNS depression, resulting with excess sedation. This combination may also result in impaired thinking, judgment, and psychomotor abilities.

Zyrtec may also impair mental function, memory and thinking capabilities. It can also alter patient’s reaction time to different stimuli. Since alcohol can produce the same effects, combining it with Zyrtec may lead to more impairment on the patients mental function.

Potentially dangerous side effects, such as excessive drowsiness and sedation can be caused. Patients have to avoid driving and operating machineries.

Elderly patients are at increased risk of side effects and also for falls and potential serious injuries because of reduced mental function. Patients on Zyrtec therapz should be advised to avoid alcohol.

Furthermore, patients should not engage in activities that require: focus, attention, and concentration such as operating heavy equipment and machinery, driving, and others.

As much as possible, patients must not drink alcohol right after taking the drug. If Zyrtec is taken under medical supervision, patients have to be sure to discuss with their doctor about alcohol consumption.

In case they experience excessive and prolonged CNS side effects that affect their normal activities, patients should contact their healthcare provider right away.


Side effects of Zyrtec and alcohol combination

Patients should never drink alcohol right after drug is taken; combining these substances increases the risk of drug interaction which can lead to side. The table below shows the incidence of side effects after Zyrtec administration in recommendable doses. The incidence can be increased if it is taken together with Alcohol.

Very Common Side effects >10 % Somnolence (2-14%) and Headache (11-14%)
Common Side Effects 1-10 % Fatigue (5.9%), Dry mouth (5%), Malaise (4%), Epistaxis (2-4%), Diarrhea (2-3%), Bronchospasm (2-3%), Vomiting (2-3%) and Dizziness (2%)
Rare Side Effects <1 % Drowsiness, Fussiness, Stomach pain, Hallucinations, Angioedema, Tremor, Tongue discoloration, Hypotension

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