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What is the most important information I should know about chlorpheniramine?

Use caution when driving, operating machinery, or performing other hazardous activities. Chlorpheniramine may cause dizziness or drowsiness. If you experience dizziness or drowsiness, avoid these activities. Use alcohol cautiously. Alcohol may increase drowsiness and dizziness while you are taking chlorpheniramine. Do not crush, chew, or break any timed release forms of chlorpheniramine. Swallow them whole. They are specially formulated to release slowly into your body.

What is chlorpheniramine?

Chlorpheniramine is an antihistamine. Chlorpheniramine blocks the effects of the naturally occurring chemical histamine in your body.

Chlorpheniramine is used to treat sneezing; runny nose; itching, watery eyes; hives; rashes; itching; and other symptoms of allergies and the common cold.

Chlorpheniramine may also be used for purposes other than those listed in this medication guide.

Who should not take chlorpheniramine?

Do not take chlorpheniramine if you have taken a monoamine oxidase inhibitor (MAOI) such as isocarboxazid (Marplan), phenelzine (Nardil), or tranylcypromine (Parnate) in the last 14 days. A very dangerous drug interaction could occur, leading to serious side effects.

Before taking this medication, tell your doctor if you have

• glaucoma or increased pressure in the eye;

• a stomach ulcer;

• an enlarged prostate, bladder problems or difficulty urinating;

• an overactive thyroid (hyperthyroidism);

• hypertension or any type of heart problems; or

• asthma.

You may not be able to take chlorpheniramine, or you may require a lower dose or special monitoring during treatment if you have any of the conditions listed above.

Chlorpheniramine is in the FDA pregnancy category B. This means that it is unlikely to harm an unborn baby. Do not take chlorpheniramine without first talking to your doctor if you are pregnant. Chlorpheniramine passes into breast milk. Infants are especially sensitive to the effects of antihistamines, and serious side effects could occur in a nursing baby. Chlorpheniramine is not recommended if you are breast-feeding a baby. Do not take chlorpheniramine without first talking to your doctor if you are nursing a baby. If you are over 60 years of age, you may be more likely to experience side effects from chlorpheniramine. You may require a lower dose of this medication.