Chlorpheniramine and phenyltoloxamine are antihistamines that reduce the effects of natural chemical histamine in the body. Histamine can produce symptoms of sneezing, itching, watery eyes, and runny nose.

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

Nalex-A is a combination medicine used to treat cough, runny or stuffy nose, sneezing, itching, and watery eyes caused by allergies, the common cold, or the flu.

Nalex-A will not treat a cough that is caused by smoking, asthma, or emphysema.

Nalex-A may also be used for purposes not listed in this medication guide.

Do not use this medicine if you have taken an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, and tranylcypromine.

Use exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended. Cough or cold medicine is usually taken only for a short time until your symptoms clear up.

Do not give this medication to a child younger than 4 years old. Always ask a doctor before giving a cough or cold medicine to a child. Death can occur from the misuse of cough and cold medicines in very young children.

Do not crush, chew, or break an extended-release tablet. Swallow it whole.

Measure liquid medicine with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

If you need surgery or medical tests, tell the surgeon or doctor ahead of time if you have taken this medicine within the past few days.

Do not take for longer than 7 days in a row. Talk with your doctor if your symptoms do not improve after 7 days of treatment, or if you have a fever with a headache or skin rash.

Store at room temperature away from moisture and heat.

Do not use this medicine if you have taken an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, and tranylcypromine.

To make sure this medicine is safe for you, tell your doctor if you have:

• a blockage in your digestive tract (stomach or intestines);

• high blood pressure, heart disease, coronary artery disease;

• glaucoma;

• liver or kidney disease;

• asthma or COPD, cough with mucus, or cough caused by smoking, emphysema, or chronic bronchitis;

• bladder obstruction or other urination problems;

• pheochromocytoma (an adrenal gland tumor);

• overactive thyroid; or

• if you take potassium (Cytra, Epiklor, K-Lyte, K-Phos, Kaon, Klor-Con, Polycitra, Urocit-K).

FDA pregnancy category C. It is not known whether Nalex-A will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medication.

This medicine can pass into breast milk and may harm a nursing baby. Antihistamines and decongestants may also slow breast milk production. Tell your doctor if you are breast-feeding a baby.

Since Nalex-A is taken when needed, you may not be on a dosing schedule. If you are taking the medication regularly, take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Drinking alcohol can increase certain side effects of Nalex-A.

Ask a doctor or pharmacist before using any other cold, cough, allergy, or sleep medicine. Antihistamines and decongestants are contained in many combination medicines. Taking certain products together can cause you to get too much of a certain drug. Check the label to see if a medicine contains an antihistamine or decongestant.

This medication may cause blurred vision and may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert and able to see clearly.

Avoid becoming overheated or dehydrated during exercise and in hot weather. Chlorpheniramine and phenyltoloxamine can decrease sweating and you may be more prone to heat stroke.

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

This medicine may cause serious side effects. Stop using this medicine and call your doctor at once if you have:

• fast or uneven heart rate;

• pounding heartbeats or fluttering in your chest;

• painful or difficult urination, little or no urinating;

• tremors, seizure (convulsions); or

• vision changes, severe dizziness, feeling like you might pass out.

Common side effects of Nalex-A may include:

• headache, dizziness, drowsiness;

• dry mouth, nose, or throat;

• upset stomach, loss of appetite, nausea, constipation;

• blurred vision;

• sleep problems (insomnia); or

• feeling restless or excited (especially in children).

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Tell your doctor about all medicines you use, including prescription and over-the-counter medicines, vitamins, and herbal products. Some medicines can cause unwanted or dangerous effects when used together. Not all possible interactions are listed in this medication guide.

Taking Nalex-A with other drugs that make you sleepy or slow your breathing can worsen these effects. Ask your doctor before taking Nalex-A with a sleeping pill, narcotic pain medicine, muscle relaxer, or medicine for anxiety, depression, or seizures.