Because Zyrtec, generic name cetirizine, can slow reactions and affect alertness, individuals should be cautious when taking the antihistamine and driving or operating machinery, advises Drugs.com. Alcohol and certain medications, such as narcotics, muscle relaxants, anti-convulsants and antidepressants, can intensify the side effects and sleepiness that Zyrtec causes. Children are especially prone to stomach pain when using cetirizine, and because it does not prevent or treat anaphylaxis, it should not be used in place of epinephrine, notes WebMD.
An individual experiencing an allergic reaction to Zyrtec requires immediate medical attention, according to Drugs.com. Symptoms include trouble breathing and swelling in the face, tongue or throat. Hives may appear. Individuals who experience serious side effects that require a doctor’s consultation may exhibit trouble urinating, severe restlessness, irregular or racing heartbeat, vision changes, and tremors. Because combining cetirizine with ethanol causes increased drowsiness, dizziness and concentration problems, alcohol should be limited or avoided.
Common side effects of Zyrtec include drowsiness, headache, dry mouth, fatigue and nausea, reports Drugs.com. Sore throat and cough are common, especially in children between 2 and 11 years of age. Children under 2 years of age may be fussy, irritable and unable to sleep when given cetirizine. Because the drug passes to a baby through breast milk, nursing mothers should avoid cetirizine.