Cetirizine is an antihistamine that reduces the natural chemical histamine in the body. Histamine can produce symptoms of sneezing, itching, watery eyes, and runny nose.

Pseudoephedrine is a decongestant that shrinks blood vessels in the nasal passages. Dilated blood vessels can cause nasal congestion (stuffy nose).

The combination of cetirizine and pseudoephedrine is used to treat cold or allergy symptoms such as nasal and sinus congestion, sneezing, itching, watery eyes, or runny nose.

Cetirizine and pseudoephedrine may also be used for other purposes not listed in this medication guide.

Do not use this medication if you have used an MAO inhibitor such as isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam), or tranylcypromine (Parnate) within the past 14 days.

You should not use cetirizine and pseudoephedrine if you are allergic to either drug, or if you have narrow-angle glaucoma, severe high blood pressure (hypertension), severe coronary artery disease, if you are unable to urinate, or if you are allergic to hydralazine (Atarax, Vistaril).

Do not use any other over-the-counter cold medication without first asking your doctor or pharmacist. Pseudoephedrine is contained in many medicines available over the counter. If you take certain products together you may accidentally take too much of this drug. Read the label of any other medicine you are using to see if it contains pseudoephedrine.

Cetirizine can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert.

Avoid drinking alcohol. It can increase some of the side effects of cetirizine.

Call your doctor if your symptoms do not improve, if they get worse, or if you also have a fever.

Do not use cetirizine and pseudoephedrine if you have used an MAO inhibitor such as isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam), or tranylcypromine (Parnate) within the past 14 days. Serious side effects can occur if you take pseudoephedrine before the MAO inhibitor has cleared from your body.

You should not use cetirizine and pseudoephedrine if you are allergic to either drug, or if you have:

• narrow-angle glaucoma;

• severe high blood pressure (hypertension);

• severe coronary artery disease;

• if you are unable to urinate; or

• if you are allergic to hydralazine (Atarax, Vistaril).

Ask a doctor or pharmacist about using cetirizine and pseudoephedrine if you have:

• heart disease, coronary artery disease, high blood pressure, or heart rhythm disorder;

• diabetes;

• a thyroid disorder;

• glaucoma;

• kidney or liver disease;

• an enlarged prostate; or

• problems with urination.

FDA pregnancy category C. It is not known whether cetirizine and pseudoephedrine is harmful to an unborn baby. Before taking this medication, tell your doctor if you are pregnant or plan to become pregnant during treatment.

Cetirizine and pseudoephedrine can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

Older adults may be more likely to have side effects from cetirizine and pseudoephedrine.