Generic Name: Chlorpheniramine/Guaifenesin (KLOR-fen-IR-a-meen/gwye-FEN-e-sin)Brand Name: Allfen A

Chlorpheniramine/Guaifenesin is used for:

Relieving allergy symptoms (eg, runny nose, watery eyes, itchy nose and throat) and dry, nonproductive cough. It may also be used for other conditions as determined by your doctor.

Chlorpheniramine/Guaifenesin is an antihistamine and expectorant combination. The antihistamine works by blocking the action of histamine, which helps reduce symptoms such as watery eyes and sneezing. The expectorant helps to loosen mucus.

Do NOT use Chlorpheniramine/Guaifenesin if:

  • you are allergic to any ingredient in Chlorpheniramine/Guaifenesin
  • you are having an asthma attack
  • you are in the last 3 months of pregnancy or are breast-feeding
  • you have angle-closure glaucoma, peptic ulcer, or difficulty urinating
  • you are taking sodium oxybate (GHB) or you have taken furazolidone or a monoamine oxidase inhibitor (MAOI) within the last 14 days

Contact your doctor or health care provider right away if any of these apply to you.

Before using Chlorpheniramine/Guaifenesin :

Some medical conditions may interact with Chlorpheniramine/Guaifenesin . Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

  • if you are pregnant, planning to become pregnant, or are breast-feeding
  • if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
  • if you have allergies to medicines, foods, or other substances
  • if you have a history of asthma; lung problems (eg, emphysema); breathing problems while sleeping (eg, sleep apnea); heart problems; high blood pressure; heart blood vessel problems; glaucoma or increased pressure in the eye; bladder, stomach, or bowel blockage; ulcers; an enlarged prostate; or seizures

Some MEDICINES MAY INTERACT with Chlorpheniramine/Guaifenesin . Tell your health care provider if you are taking any other medicines, especially any of the following:

  • Barbiturates (eg, phenobarbital), furazolidone, MAOIs (eg, phenelzine), sodium oxybate (GHB), or tricyclic antidepressants (eg, amitriptyline) because they may increase the risk of Chlorpheniramine/Guaifenesin 's side effects

This may not be a complete list of all interactions that may occur. Ask your health care provider if Chlorpheniramine/Guaifenesin may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

How to use Chlorpheniramine/Guaifenesin :

Use Chlorpheniramine/Guaifenesin as directed by your doctor. Check the label on the medicine for exact dosing instructions.

  • Take Chlorpheniramine/Guaifenesin by mouth with or without food. If stomach upset occurs, take with food to reduce stomach irritation.
  • If you miss a dose of Chlorpheniramine/Guaifenesin , take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.

Ask your health care provider any questions you may have about how to use Chlorpheniramine/Guaifenesin .

Important safety information:

  • Chlorpheniramine/Guaifenesin may cause drowsiness or dizziness. These effects may be worse if you take it with alcohol or certain medicines. Use Chlorpheniramine/Guaifenesin with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
  • Do not drink alcohol or use medicines that may cause drowsiness (eg, sleep aids, muscle relaxers) while you are using Chlorpheniramine/Guaifenesin ; it may add to their effects. Ask your pharmacist if you have questions about which medicines may cause drowsiness.
  • The risk of drowsiness or other side effects may be greater if you take Chlorpheniramine/Guaifenesin in high doses or for a long time. Do NOT take more than the recommended dose without checking with your doctor.
  • If your symptoms do not get better or if they get worse, check with your doctor.
  • Chlorpheniramine/Guaifenesin may cause dry mouth. Taking sips of water or sucking ice chips may help. Chewing sugarless gum or sucking hard sugarless candy may also help.
  • Chlorpheniramine/Guaifenesin has chlorpheniramine in it. Before you start any new medicine, check the label to see if it has chlorpheniramine in it too. If it does or if you are not sure, check with your doctor or pharmacist. Do not take any other antihistamine while you take Chlorpheniramine/Guaifenesin .
  • Chlorpheniramine/Guaifenesin may cause you to become sunburned more easily. Avoid the sun, sunlamps, or tanning booths until you know how you react to Chlorpheniramine/Guaifenesin . Use a sunscreen or wear protective clothing if you must be outside for more than a short time.
  • Chlorpheniramine/Guaifenesin may interfere with certain lab tests. Be sure your doctor and lab personnel know you are taking Chlorpheniramine/Guaifenesin .
  • If you are scheduled for a skin test, talk to your doctor. You may need to stop taking Chlorpheniramine/Guaifenesin for a few days before the tests.
  • Tell your doctor or dentist that you take Chlorpheniramine/Guaifenesin before you receive any medical or dental care, emergency care, or surgery.
  • Use Chlorpheniramine/Guaifenesin with caution in the ELDERLY; they may be more sensitive to its effects.
  • Chlorpheniramine/Guaifenesin should be used with extreme caution in CHILDREN younger than 6 years old; safety and effectiveness in these children have not been confirmed.
  • PREGNANCY and BREAST-FEEDING: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Chlorpheniramine/Guaifenesin while you are pregnant. Do not use Chlorpheniramine/Guaifenesin if you are in the last 3 months of pregnancy. It is not known if Chlorpheniramine/Guaifenesin is found in breast milk. Do not breast-feed while taking Chlorpheniramine/Guaifenesin .

Possible side effects of Chlorpheniramine/Guaifenesin :

All medicines may cause side effects, but many people have no, or minor side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Constipation; diarrhea; dizziness; drowsiness; dry mouth, nose, or throat; headache; loss of appetite; nausea; upset stomach; vomiting; weakness.

Seek medical attention right away if any of these SEVERE side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); blurred vision or other vision changes; changes in thinking or behavior; confusion; difficult or painful urination; excitability; fainting; fast, slow, or irregular heartbeat; fever, chills, or persistent sore throat; flushing; hallucinations; inability to urinate; loss of coordination; mood or mental changes; nervousness or anxiety; ringing in the ears or other hearing changes; seizures; severe drowsiness; severe dry mouth, nose, or throat; severe or persistent dizziness, lightheadedness, or headache; shortness of breath; slow or irregular breathing; tremor; trouble sleeping; unusual bruising or bleeding; unusual tiredness or weakness.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. You may also report side effects at

If OVERDOSE is suspected:

Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center (, or emergency room immediately. Symptoms may include confusion; fever; flushing; hallucinations; seizures; severe dizziness or lightheadedness; severe drowsiness; trouble sleeping.

Proper storage of Chlorpheniramine/Guaifenesin :

Store Chlorpheniramine/Guaifenesin at room temperature, between 59 and 86 degrees F (15 and 30 degrees C). Store away from heat, moisture, and light. Do not store in the bathroom. Keep Chlorpheniramine/Guaifenesin out of the reach of children and away from pets.

General information:

  • If you have any questions about Chlorpheniramine/Guaifenesin , please talk with your doctor, pharmacist, or other health care provider.
  • Chlorpheniramine/Guaifenesin is to be used only by the patient for whom it is prescribed. Do not share it with other people.
  • If your symptoms do not improve or if they become worse, check with your doctor.

This information is a summary only. It does not contain all information about Chlorpheniramine/Guaifenesin . If you have questions about the medicine you are taking or would like more information, check with your doctor, pharmacist, or other health care provider.