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Overview: Chlorpheniramine is an antihistamine that is taken to relieve allergy symptoms. It is available over the counter (OTC). The most common side effect is drowsiness, but it may cause excitability in some children. Do not drive or do other activities that require alertness or coordination until you know how chlorpheniramine affects you. Call your health care provider right away if you are having trouble peeing or cannot empty your bladder while taking chlorpheniramine.

Uses

What is chlorpheniramine used for?

Chlorpheniramine is commonly taken to help treat allergy symptoms, such as a runny nose, itchy or watery eyes, sneezing, or an itchy nose or throat. 

Chlorpheniramine may also be used for other conditions as determined by your health care provider.

How does chlorpheniramine work (mechanism of action)?

Chlorpheniramine is an antihistamine. It works by blocking the effect of a substance in your body called histamine.

How is chlorpheniramine supplied (dosage forms)?

Brands and other names

  • Aller-Chlor
  • Chlorphen
  • ClorRelief
  • Chlor-Trimeton
  • ChlorTabs

Example dosage forms and strengths

  • 0.5% oral spray
  • 4 mg oral tablets
  • 12 mg extended-release oral tablets

How should I store chlorpheniramine?

Chlorpheniramine should be stored at room temperature, between 68 F and 77 F (20 C and 25 C). It can be exposed to temperatures between 59 F and 86 F (15 C and 30 C) for shorter periods of time, such as when you’re transporting it. Store it in a cool, dry place.

Side Effects

What are the most common side effects of chlorpheniramine?

The most common side effects of chlorpheniramine are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Drowsiness
  • Excitability (especially in children)

There may be other side effects of chlorpheniramine that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of chlorpheniramine?

While less common, the most serious side effects of chlorpheniramine are described below, along with what to do if they happen.

Severe Allergic Reactions. Chlorpheniramine may cause allergic reactions, which can be serious. Stop taking chlorpheniramine and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Inability to Empty Bladder (Urinary Retention). Chlorpheniramine might make it harder to empty your bladder, especially if you already have a blockage. Stop taking chlorpheniramine and call your health care provider right away if you are having trouble peeing or cannot empty your bladder.

Warnings & Precautions

Who should not use chlorpheniramine?

Allergies to Ingredients. People who are allergic to any of the following should not take chlorpheniramine.

  • Chlorpheniramine
  • Chlorphen
  • ClorRelief
  • Chlor-Trimeton
  • ChlorTabs
  • Any of the ingredients in the specific product being used

Your pharmacist can tell you all of the ingredients in the specific chlorpheniramine products they stock.

What should I know about chlorpheniramine before using it?

Keep chlorpheniramine out of the reach of children.

There are several forms of chlorpheniramine available. Read and follow the instructions for the product you have and make sure you understand how to use it properly. If you have any questions, talk to your pharmacist or other health care provider.

Chlorpheniramine can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination until you know how chlorpheniramine affects you.

Do not use chlorpheniramine to make a child sleepy. Talk with your health care provider if you have questions. 

What should I tell my health care provider before using chlorpheniramine?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if chlorpheniramine is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have any of the following. 

Other Medicines and Supplements. Chlorpheniramine may interact with other medicines and supplements. Before taking chlorpheniramine, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how chlorpheniramine could affect pregnancy or harm an unborn baby. Tell your health care provider if you are pregnant or plan to become pregnant. Your health care provider will let you know if you should take chlorpheniramine while you are pregnant or trying to get pregnant.

Breastfeeding. Chlorpheniramine passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should take chlorpheniramine while breastfeeding.

Interactions

Does chlorpheniramine interact with foods or drinks?

There are no known interactions between chlorpheniramine and foods or non-alcoholic drinks.

Do not drink alcohol while you are taking chlorpheniramine. The risk of drowsiness may be increased if you drink alcohol while taking chlorpheniramine.

Does chlorpheniramine interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any medicine that causes sleepiness, such as prescription pain medicines, other allergy medicines, sleep medicines, and medicines for anxiety.

This may not be a complete list of medicines that can interact with chlorpheniramine. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much chlorpheniramine?

If you or someone else has taken too much chlorpheniramine, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of chlorpheniramine?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.