What is Chlorpheniramine?

Chlorpheniramine is an antihistamine that reduces the effects of the natural chemical histamine in the body. Histamine can cause symptoms such as sneezing, itching, watery eyes and runny nose, which can be relieved with the help of this medicine. Also, this drug blocks another natural substance called acetylcholine, which is made by the body. Blocking acetylcholine helps reduce symptoms such as runny eyes and nose. In the following, with a complete definition of the mechanism of action of chlorpheniramine, we will examine the uses, pharmaceutical forms, how to use, precautions and contraindications for this drug.

Pharmaceutical forms of chlorpheniramine

The pharmaceutical forms of chlorpheniramine include 4 mg, 8 mg and 12 mg tablets, 2 mg/ml suspension and 2 mg/5 ml syrup. Also, the medicines of this drug group are antihistamine decongestant, diphenhydramine compound, brompheniramine maleate, carbinoxamine, clemastine, cyproheptadine, diphenhydramine, doxylamine, promethazine, triprolidine, etc.

Chlorpheniramine uses

Chlorpheniramine relieves redness, itching and watery eyes. Sneezing, itchy nose or throat, and runny nose are common causes of allergies, hay fever, and the common cold. This medication helps control the symptoms of a cold or allergy, but does not treat the cause of the symptoms (disease) or speed recovery. This drug is in a class of drugs called antihistamines. It works by blocking the action of histamine, a substance in the body that causes allergic symptoms.

Pharmacological effects and mechanism of action of chlorpheniramine drug

The mechanism of action of chlorpheniramine is the antagonist of H1 histamine receptor in blood vessels, respiratory system and digestive system. elimination half-life of this drug 10-13 hours (children); 14-24 hours (adults). The plasma peak time is 2-3 hours (range 1-6 hours) and bound protein is 29-37%. Its metabolites include monodesmethylchlorpheniramine, didesmethylchlorpheniramine, and are excreted through urine.

Dosage of chlorpheniramine

Regular capsules and tablets, chewable tablets, and liquid are usually taken every 4 to 6 hours as needed. Long-release (long-acting) tablets and capsules are usually prescribed by a doctor twice a day, in the morning and in the evening. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain anything you don’t understand. Before using 2 or more medications at the same time, carefully check the labels of over-the-counter cold and cough medications. These products may contain the same active ingredient and their use together can cause drug interactions.

Time to take chlorpheniramine tablets

Over-the-counter cough and cold medicines, including those containing chlorpheniramine, can cause serious side effects or death in young children. Do not give these medicines to children under 4 years of age. If you are giving these medications to children 4 to 11 years of age, use caution and follow the manufacturer’s directions carefully. Chlorpheniramine is sometimes used in combination with other fever and pain relievers, expectorants, cough suppressants, and decongestants. Note that taking these drugs at the same time does not cause problems for your health.

How to use chlorpheniramine

1. To treat allergic rhinitis, tablets or syrup of this drug 4 mg every 4 to 6 hours, not more than 24 mg per day. Extended-release tablets of 8 mg every 8 to 12 hours or 12 mg every 12 hours, with a total dose not to exceed 24 mg per day. Also, the long-release capsule is used, 12 mg per day, which should not be more than 24 mg per day.
2. Permanent and seasonal allergic and vasomotor rhinitis, relief of cold symptoms, urticaria, angioedema, anaphylactic reactions, itching, allergic conjunctivitis, etc. One of the uses of this drug is that the dosage should be specified with a doctor’s prescription (or the drug information on the package).
3. For the treatment of allergic rhinitis in children 2 to 6 years of age, 1 mg every 4 to 6 hours, not to exceed 12 mg per day or sustained release HS. For people over 12 years of age, tablets or syrup of 4 mg every 4 to 6 hours, not more than 24 mg per day.
4. Extended-release tablets 8 mg every 8 to 12 hours or 12 mg every 12 hours, not to exceed 24 mg per day.
5. Sustained-release capsules 8-12 mg every 8-12 hours, which can be used up to 16-24 mg per day.

Precautions

1. Tell your doctor and pharmacist if you are allergic to chlorpheniramine, any other drugs, or any of the ingredients of chlorpheniramine that you plan to use.
2. Tell your doctor and pharmacist what prescription and over-the-counter medications, vitamins, nutritional supplements, and herbal remedies you are taking. For example, if you are taking cold, hay fever or allergy medications, anxiety, depression or seizure medications, muscle relaxants, narcotic pain medications, sedatives, sleeping pills, etc., consult your doctor regarding the risks of simultaneous use and drug interactions.
3. Tell your doctor if you have or have ever had asthma, emphysema, chronic bronchitis, or any other lung disease. If you have a history of glaucoma (a condition in which increased pressure in the eye can lead to gradual loss of vision), ulcers, diabetes, difficulty urinating (due to an enlarged prostate gland), heart disease, high blood pressure, Seizures or an overactive thyroid gland, consult a doctor.
4. Pregnant women, nursing mothers or people who plan to become pregnant should consult a doctor regarding the risks of using this medicine.
5. If you are having surgery, including dental surgery, tell your doctor or dentist that you are taking chlorpheniramine.
6. If you are 65 years of age or older, talk to your doctor about the risks and benefits of taking chlorpheniramine. Elderly people should not usually take chlorpheniramine because it is not as safe or effective as other drugs that can be used to treat the same condition.

Chlorpheniramine contraindications

1. Documented hypersensitivity
2. Diseases of the lower respiratory tract, for example asthma
3. Premature babies and infants
4. Women nurses
5. Acute asthma, sleep apnea

Side effects of chlorpheniramine tablets

Dizziness, weakness, coordination disorder, muscle weakness, restlessness, insomnia, tremors, euphoria, nervousness, delirium, heart palpitations, seizures (rare), anorexia, nausea, vomiting, etc. are some of the side effects of chlorpheniramine. . If any of the side effects of this drug get worse or the disease does not improve, stop using the drug and inform the doctor. Most people who take this drug have no serious side effects. In case of serious side effects or specific allergic reactions, stop taking the drug and inform your doctor.

1. blood pressure
2. CNS depression, dizziness and lethargy
3. Drowsiness
4. Sedation from mild drowsiness to deep sleep (most cases)
5. Coordination disorder
6. muscle weakness
7. Restlessness, insomnia, tremors, euphoria, nervousness, delirium, palpitations, seizures are less common.
8. Epigastric distress
9. Anorexia
10. Nausea, vomiting, diarrhea and constipation
11. Cholestasis, hepatitis, liver failure, liver dysfunction, jaundice are rare.
12. Tachycardia, palpitations ECG changes (eg widened QRS)
13. Arrhythmia (such as extrasystole, heart block)

Drug interaction of chlorpheniramine

1. Class X interactions (avoid): simetropium, eloxadoline, glycopyrrolate (oral inhalation), glycopyrronium (topical), ipratropium (oral inhalation), levosulpiride, orphenadrine, oxatomide, oxomazine, paraldehyde, pitolisant, potassium chloride, potassium citrate, rufenacin, thalidomide, Tiotropium, omeclidinium, aclidinium, azelastine (nasal), bromperidol
2. Reducing the effects of drugs by chlorpheniramine: acetylcholinesterase inhibitors, benzylpenicilloylpolylysine, betahistine, gastrointestinal agents (prokinetics), hyaluronidase, itopride, levosulpiride, nitroglycerin, pitolisant, secretin
3. Enhancement of the effects of drugs by chlorpheniramine: glucagon, glycopyrrolate (oral inhalation), methotrexate, metyrosine, mirabegron, opioid agonists, orphenadrine, oxycodone, paraldehyde, prehexiline, piribdil, potassium chloride, potassium citrate, pramipexol, ramosteron, rufenacin, ropinirol, Rotigotine, SSRIs, suvarexant, ethanol, amzinium, anticholinergic agents, azelastine (nasal), blonanserin, brexanolone, buprenorphine, simtropium, clozapine, CNS depressants, eloxadoline, flunitrazepam
4. Increased effects of chlorpheniramine by drugs: chlorpheniramine carbamate, clobazam, cobisstat, moderate and strong CYP2D6 inhibitors, dacomitinib, darunavir, dimetinden (topical), doxylamine, dronabinol, droperidol, sketamine, glycopyrronium (topical), hydroxyzine, imatinib, ipratropium ( oral inhalation), kava kava, lemborexant, abiraterone acetate, aclidinium, ajmaline, alizapride, amantadine, asonapravir, products containing botulinum toxin, brimonidine (topical), bromoprid, bromperidol, cannabidiol, cannabis, chloral betaine, chlormethiazole

Use of chlorpheniramine during pregnancy and breastfeeding

Antihistamine exposure in the first trimester was not associated with an increased risk of malformations. No specific study or research is available regarding the risks of using this drug during pregnancy. Note that its use during pregnancy is recommended only when the benefits outweigh the risks. This drug is excreted in human milk, so caution should be exercised when administering it to lactating women. Infants should be monitored for irritability or drowsiness. Antihistamines may temporarily decrease the mother’s serum prolactin concentration if administered to the infant before breastfeeding.

Storage conditions for chlorpheniramine

Chlorpheniramine should be stored at room temperature and away from light. It is also important to keep all medications out of the reach of children, as many forms of medication (such as weekly tablets and eye drops, creams, patches, and inhalers) are not child-resistant and can be easily opened by young children. . Unnecessary medications should be disposed of in specific ways to ensure that pets, children, and other people cannot ingest them.

The last word about the drug chlorpheniramine

As described in this article from Green Positive Online Pharmacy magazine, chlorpheniramine is an antihistamine for the relief of allergy, hay fever, and cold symptoms that works by blocking a certain natural substance (histamine) that your body produces during an allergic reaction. he does. The mechanism of action of this drug has caused its high use in relieving the symptoms of colds and various allergies. However, the appropriate use and dosage of this drug should be determined by a doctor or pharmacist to avoid side effects.

Site source: Medscape