Before taking clemastine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: breathing problems (such as asthma, emphysema), a certain eye problem (glaucoma), heart problems, high blood pressure, liver disease, seizures, stomach problems (such as ulcers, blockage), overactive thyroid (hyperthyroidism), urination problems (such as trouble urinating due to enlarged prostate, urinary retention).

This drug may make you dizzy or drowsy or blur your vision. Alcohol or marijuna (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness or clear vision until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

Liquid preparations of this product may contain sugar and/or alcohol. Caution is advised if you have diabetes, alcohol dependence, or liver disease. Ask your doctor or pharmacist about the safe use of this product.

Older adults may be more sensitive to the side effects of this drug, especially drowsiness, constipation, problems urinating, or confusion. Drowsiness and confusion can increase the risk of falling.

Children may be more sensitive to the effects of antihistamines. In young children, this medication may cause agitation/excitement instead of drowsiness.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This drug passes into breast milk and may have undesirable effects on a nursing infant. Consult your