Chlo Hist is a combination medication containing chlophedianol (a cough suppressant) and dexbrompheniramine (an antihistamine). It can be taken by adults and children to help with certain allergy and common cold symptoms, such as cough, runny nose, and itchy eyes. Chlo Hist (chlophedianol / dexbrompheniramine) is taken by mouth, typically every 6 hours, as needed. It's available as a brand name oral solution (liquid) that you can buy over the counter. Some side effects of this medication include include dizziness and sleepiness.
Temporary relief of:
Cough from minor throat irritation
Runny nose
Sneezing
Itchy nose or throat
Itchy and watery eyes
Chlo Hist (chlophedianol / dexbrompheniramine) is a combination of two medications.
Chlophedianol is a cough suppressant. It works by blocking signals from the part of your brain that makes you cough.
Dexbrompheniramine is a first-generation antihistamine. It blocks a natural substance in your body called histamine. This helps relieve runny nose, itchy nose, and sneezing.
Source: DailyMed
Side effects that you should report to your care team as soon as possible:
Side effects that usually do not require medical attention (report these to your care team if they continue or are bothersome):
Available over the counter
Liquid, so good option if you have trouble swallowing pills
Easier to take a combination product instead of 2 separate medications to treat cough or allergy symptoms
Option for children ages 6 years and older
Can cause sleepiness or dizziness
Can cause excitability (hyperactivity) in children
Might need to take multiple times a day
Older adults at higher risk for drowsiness
You might feel sleepy after taking Chlo Hist (chlophedianol / dexbrompheniramine) . Don't drive or do anything that requires you to be alert until you know how Chlo Hist (chlophedianol / dexbrompheniramine) affects you.
It's best to avoid drinking alcohol while taking Chlo Hist (chlophedianol / dexbrompheniramine) because doing so can worsen sleepiness and dizziness. And if you have a cold or flu, drinking alcohol can make it harder for your body to recover.
While Chlo Hist (chlophedianol / dexbrompheniramine) usually makes adults sleepy, it's possible for children who use Chlo Hist (chlophedianol / dexbrompheniramine) to become overly excited or energetic. If this happens to your child, speak to your child's pediatrician.
Be sure to use a medication dose cup, spoon, or syringe to measure out your dose of Chlo Hist (chlophedianol / dexbrompheniramine) . Don't use household spoons because they're not accurate and might cause you to take the wrong amount of this medication.
Don't start any new medications while taking Chlo Hist (chlophedianol / dexbrompheniramine) , especially other cough suppressants (antitussives) or antihistamines, without talking to your primary care provider or pharmacist first. Doing so can raise your risk of overdose and severe side effects, including seizures, hallucinations (seeing things that are not real), daytime sleepiness, dizziness, or even death.
Stop taking Chlo Hist (chlophedianol / dexbrompheniramine) and talk to your primary care provider if your cough lasts for longer than 1 week, goes away and comes back, or you also have a fever, rash, or headache. A cough that doesn't go away can be a sign of a serious condition that you should get checked out.
Chlo Hist (chlophedianol / dexbrompheniramine) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk factors: Taking more than the recommended dose | Taking other medications that cause drowsiness | Drinking alcohol
Chlo Hist (chlophedianol / dexbrompheniramine) can make you very sleepy, which can affect your ability to focus, think, or react. This side effect is more likely to happen or be more intense if you're over 65 years old, drink alcohol while you're taking this medication, or take other medications that cause sleepiness (e.g., opioids, benzodiazepines, sleep medications). Don't drive or operate machinery until you know how Chlo Hist (chlophedianol / dexbrompheniramine) affects you.
Chlo Hist (chlophedianol / dexbrompheniramine) contains a cough suppressant (chlophedianol) and an antihistamine (dexbrompheniramine), which are in many other over-the-counter products. Using more than one medication containing a cough suppressant and antihistamine, including products used on the skin, can lead to an accidental overdose. This can result in serious side effects, including daytime sleepiness, dizziness, seizures, hallucinations (seeing things that aren't real), or even death.
Tell your primary care provider or pharmacist about the medications you take before starting Chlo Hist (chlophedianol / dexbrompheniramine) to make sure it's safe for you. Don't start any new medications while taking Chlo Hist (chlophedianol / dexbrompheniramine) without talking to your care team. To prevent an accidental overdose, read package labels carefully. If you're not sure if a product has a cough suppressant or an antihistamine, ask your pharmacist. If you or your loved one experiences an accidental overdose, get medical help right away or contact a poison control center at 1-800-222-1222.
Risk factors: Cough from smoking, asthma, or emphysema | Mucus-producing cough | Breathing problems (e.g., emphysema, long-term bronchitis) | Glaucoma | Urinary problems
Don't take Chlo Hist (chlophedianol / dexbrompheniramine) if you have any of the risk factors listed above unless your primary care provider said it's safe to do so. Taking Chlo Hist (chlophedianol / dexbrompheniramine) can worsen your condition(s) and cause serious side effects. Make sure your primary care provider knows about all medical conditions you have or have had in the past before starting Chlo Hist (chlophedianol / dexbrompheniramine) .
Each 5 mL of Chlo Hist (chlophedianol / dexbrompheniramine) contains 12.5 mg of chlophedianol and 1 mg of dexbrompheniramine.
Adults and children ages 12 years and older: The typical dose is 10 mL by mouth every 6 hours. Don't take more than 40 mL in 24 hours.
Children ages 6 to under 12 years old: The typical dose is 5 mL by mouth every 6 hours. Don't take more than 20 mL in 24 hours.
Child under 6 years old: Don't use. Talk with your child's pediatrician.
Temporary relief of:
Cough from minor throat irritation
Runny nose
Sneezing
Itchy nose or throat
Itchy and watery eyes
Cough
Sneezing
Runny nose
Itchy or watery eyes
Itching of the nose and throat
Cough
Runny nose
Itchy or watery eyes
Itching of the nose and throat
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Department of Justice/Drug Enforcement Administration. (2020). Narcotics.
PubChem. (2024). Clofedanol. National Center for Biotechnology Information.
R.A. McNeil Company. (2024). Chlo Hist chlophedianol hydrochloride, dexbrompheniramine maleate liquid [package insert]. DailyMed.
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