Chlorpheniramine is an antihistamine used to relieve symptoms of allergy, hay fever, and the common cold. These symptoms include rash, watery eyes, itchy eyes/nose/throat/skin, cough, runny nose, and sneezing.
This medication works by blocking a certain natural substance (histamine) that your body makes during an allergic reaction. By blocking another natural substance made by your body (acetylcholine), it helps dry up some body fluids to relieve symptoms such as watery eyes and runny nose.
Cough-and-cold products have not been shown to be safe or effective in children younger than 6 years. Therefore, do not use this product to treat cold symptoms in children younger than 6 years unless specifically directed by the doctor. Some products (such as long-acting tablets/capsules) are not recommended for use in children younger than 12 years. Ask your doctor or pharmacist for more details about using your product safely.
These products do not cure or shorten the length of the common cold and may cause serious side effects. To decrease the risk for serious side effects, carefully follow all dosage directions. Do not use this product to make a child sleepy. Do not give other cough-and-cold medication that might contain the same or similar ingredients (see also Drug Interactions section). Ask the doctor or pharmacist about other ways to relieve cough and cold symptoms (such as drinking enough fluids, using a humidifier or saline nose drops/spray).
If you are taking the over-the-counter product, read all directions on the product package before taking this medication. If you have any questions, consult your pharmacist. If your doctor has prescribed this medication, take it as directed.
Take the tablet, capsule, or liquid form by mouth with or without food. Follow the directions for dosing on the label, or take as directed by your doctor. This medication may be taken with food or milk if stomach upset occurs.
If you are taking the extended-release capsules, swallow them whole. Do not crush or chew extended-release capsules or tablets. Doing so can release all of the drug at once, increasing the risk of side effects. Also, do not split extended-release tablets unless they have a score line and your doctor or pharmacist tells you to do so. Swallow the whole or split tablet without crushing or chewing.
If you are using the liquid form, use a medication measuring device to carefully measure the prescribed dose. Do not use a household spoon. If your liquid form is a suspension, shake the bottle well before each dose.
Your dosage is based on your age, medical condition, and response to therapy. Do not increase your dose or take this medication more often than recommended by your doctor or the package instructions without your doctor's approval. Take this medication regularly in order to get the most benefit from it. To help you remember, take it at the same time(s) each day.
If your condition persists or worsens, or if you think you may have a serious medical problem, seek immediate medical attention.
Drowsiness, dizziness, headache, constipation, stomach upset, blurred vision, decreased coordination, or dry mouth/nose/throat may occur. These effects may decrease as your body adjusts to the medication. If any of these effects persist or worsen, contact your doctor or pharmacist promptly.
To relieve dry mouth, suck on (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water, or use a saliva substitute. Chlorpheniramine can dry up and thicken mucus in your lungs, making it more difficult to breathe and clear your lungs. To help prevent this effect, drink plenty of fluids unless otherwise directed by your doctor.
If you are using a sustained-release product, an empty tablet shell may appear in your stool. This is harmless.
If your doctor has prescribed this medication, remember that he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor immediately if any of these unlikely but serious side effects occur: mental/mood changes (e.g., hallucinations, irritability, nervousness, confusion), ringing in the ears, trouble urinating.
A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Before taking chlorpheniramine, tell your doctor or pharmacist if you are allergic to it; or to dexchlorpheniramine; 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 (e.g., asthma, emphysema), a certain eye problem (glaucoma), heart problems, high blood pressure, liver disease, seizures, stomach problems (e.g., ulcers, blockage), overactive thyroid (hyperthyroidism), urination problems (e.g., trouble urinating due to enlarged prostate, urinary retention).
This drug may make you dizzy or drowsy or cause blurred vision. Do not drive, use machinery, or do any activity that requires alertness or clear vision until you are sure you can perform such activities safely. Limit the use of alcohol and certain other medications that cause drowsiness. (See also Drug Interactions.)
To minimize dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.
Liquid products may contain aspartame, sugar and/or alcohol. Caution is advised if you have diabetes, alcohol dependence, liver disease, phenylketonuria (PKU), or any other condition that requires you to limit/avoid these substances in your diet. Ask your doctor or pharmacist about using this product safely.
Older adults may be more sensitive to the side effects of this drug, especially drowsiness, dizziness, low blood pressure, confusion, constipation, or trouble urinating. Drowsiness, dizziness, 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.
Based on information from related drugs, this medication may pass into breast milk. Consult your doctor before breast-feeding.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
Some products that may interact with this drug include: antihistamines applied to the skin (such as diphenhydramine cream, ointment, spray), antispasmodics (e.g., atropine, belladonna alkaloids), MAO inhibitors (isocarboxazid, linezolid, methylene blue, moclobemide, phenelzine, procarbazine, rasagiline, selegiline, tranylcypromine), drugs for Parkinson's disease (e.g., anticholinergics such as benztropine, trihexyphenidyl), scopolamine, tricyclic antidepressants (e.g., amitriptyline).
Tell your doctor or pharmacist if you also take drugs that cause drowsiness such as: certain antihistamines (e.g., diphenhydramine), anti-seizure drugs (e.g., carbamazepine), medicine for sleep or anxiety (e.g., alprazolam, diazepam, zolpidem), muscle relaxants, narcotic pain relievers (e.g., codeine), psychiatric medicines (e.g., chlorpromazine, risperidone, amitriptyline, trazodone). Check the labels on all your medicines (e.g., cough-and-cold products) because they may contain drowsiness-causing ingredients. Ask your pharmacist about the safe use of those products.
Chlorpheniramine is very similar to dexchlorpheniramine. Do not use medications containing dexchlorpheniramine while using chlorpheniramine.
This medication may interfere with certain laboratory tests (including allergy skin testing), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.
If overdose is suspected, contact a poison control center or emergency room immediately. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: large pupils, flushing, fever, hallucinations, weakness, shaking (tremor), muscle twitching, loss of consciousness, seizures. In children, excitement may occur first, and may be followed by loss of coordination, drowsiness, loss of consciousness, seizures.
If your doctor has prescribed this medication, do not share it with others.
Keep all regular medical and laboratory appointments.
Do not take for several days before allergy testing because test results can be affected.
If you miss a dose, take it as soon as you remember. If it is near the time of your next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.
Store at room temperature between 59-86 degrees F (between 15-30 degrees C) away from moisture and light. Store in a tightly closed container. Do not store in the bathroom. Do not freeze liquid forms of this medication. Keep all medicines away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.
Information last revised March 2014. Copyright(c) 2014 First Databank, Inc.
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