Zyrtec, also called Cetirizine, is an antihistamine, or an H1 Receptor. It is used to treat hay fever, and hives. Zyrtec works by blocking the effects of a substance called Histamine, which is naturally produced by the body.
Be sure to tell your doctor of any allergies you have whether it is to medication or food, preservatives, or dyes. Also, tell your doctor of any other medications you are taking, including vitamins and supplements, and any medical conditions you may have.
If you miss a dose of this medicine, take it as soon as you remember, unless it is almost time for your next dose. Do NOT double doses.
Tell your doctor immediately if any of the following side effects occur: chest tightness ; feeling of warmth, redness of the face, neck, arms and occasionally, upper chest; large, hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, sex organs; shortness of breath, or difficult or labored breathing.
Let your doctor know if you have bothersome or continuing: back pain; body aches or pain; chills; coughing; difficulty in moving; dizziness; drowsiness; ear congestion; earache; fever; headache; joint pain; loss of voice; muscle aching or cramping; muscle pains or stiffness; nasal congestion; nausea; pain in arms or legs; pain or tenderness around eyes or cheekbones; painful menstrual bleeding; ringing or buzzing in ears; runny or stuffy nose; sneezing; sore throat; stomach upset; swollen joints; unusual feeling of tiredness or weakness; or a viral infection (such as cold and flu).
Cetirizine HCl is an orally active and selective H1-receptor antagonist. The chemical name is (±) - [2- [4- [ (4-chlorophenyl)phenylmethyl] -1- piperazinyl] ethoxy]acetic acid, dihydrochloride. Cetirizine HCl is a racemic compound with an empirical formula of C21H25C1N2O3·2HCl. The molecular weight is 461.82. Cetirizine HCl is a white, crystalline powder and is water soluble. Zyrtec tablets are formulated as white, film-coated, rounded-off rectangular shaped tablets for oral administration and are available in 5 and 10 mg strengths. Inactive Ingredients: Lactose; magnesium stearate; povidone; titanium dioxide; hydroxypropyl methylcellulose; polyethylene glycol; and corn starch. Zyrtec syrup is a colorless to slightly yellow syrup containing cetirizine HCl at a concentration of 1 mg/ml (5 mg/5 ml) for oral administration. The pH is between 4 and 5. Inactive Ingredients: Banana flavor; glacial acetic acid; glycerin; grape flavor; methylparaben; propylene glycol; propylparaben; sodium acetate; sugar syrup; and water.
Zyrtec has the following structural formula: