Usage
- This combination medication is prescribed for the temporary relief of cough and upper respiratory symptoms, including nasal congestion, associated with allergies or the common cold. It is also used as an expectorant for productive cough.
- Pharmacological Classification: This drug is a combination of an antihistamine, a cough suppressant, and an expectorant.
- Mechanism of Action: Chlorpheniramine maleate is an antihistamine that blocks the effects of histamine, reducing allergy symptoms like sneezing, runny nose, and itching. Dextromethorphan hydrobromide is a cough suppressant that acts on the cough center in the brain. Guaifenesin is an expectorant that thins and loosens mucus in the airways, making it easier to cough up.
Alternate Names
- While this specific combination may not have a widely recognized international nonproprietary name (INN), its individual components do: chlorpheniramine maleate, dextromethorphan hydrobromide, and guaifenesin.
- Brand Names: This combination is marketed under various brand names, one example being Cofgel Cough Syrup. Numerous other formulations containing these ingredients exist under different brand names.
How It Works
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Pharmacodynamics: Chlorpheniramine reduces histamine-mediated responses such as sneezing, rhinorrhea, and itching. Dextromethorphan suppresses the cough reflex by acting centrally in the medulla. Guaifenesin increases respiratory tract fluid secretions, making it easier to expectorate mucus.
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Pharmacokinetics:
- Absorption: Chlorpheniramine is well-absorbed from the gastrointestinal tract. Dextromethorphan is also absorbed orally. Guaifenesin is readily absorbed after oral administration.
- Metabolism: Chlorpheniramine is extensively metabolized in the liver. Dextromethorphan is metabolized in the liver by the cytochrome P450 enzyme system, specifically CYP2D6. Guaifenesin is metabolized by oxidation, mostly to β-(2-methoxyphenoxy)-lactic acid.
- Elimination: Chlorpheniramine is primarily excreted in the urine. Dextromethorphan is excreted in the urine, primarily as metabolites. Guaifenesin is excreted in the urine.
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Mode of Action: Chlorpheniramine competitively inhibits the binding of histamine to H1 receptors. Dextromethorphan acts centrally in the medulla to elevate the cough threshold. Guaifenesin is thought to stimulate receptors in the gastric mucosa, leading to increased respiratory tract secretions.
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Receptor Binding, Enzyme Inhibition, or Neurotransmitter Modulation: Chlorpheniramine binds to H1 histamine receptors. Dextromethorphan acts on sigma opioid receptors and NMDA receptors in the brain, although its precise mechanism for cough suppression is not fully understood. Guaifenesin’s mechanism of action at the receptor level is not completely elucidated.
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Elimination Pathways: Chlorpheniramine and dextromethorphan are primarily eliminated via hepatic metabolism followed by renal excretion. Guaifenesin is excreted in the urine, both as the unchanged drug and its metabolites.
Dosage
Standard Dosage
Adults:
- A typical dose in a syrup formulation containing 2 mg chlorpheniramine maleate, 10 mg dextromethorphan hydrobromide, and 100 mg guaifenesin per 5 mL is 10 mL (two teaspoonfuls) every 6 hours, not to exceed four doses in a 24-hour period. Dosing may vary based on the specific formulation.
Children:
- 6 to 12 years: 5 mL (one teaspoonful) every 6 hours, not exceeding four doses in 24 hours.
- Under 6 years: This combination is not typically recommended for children under 6 years of age.
- Pediatric Safety Considerations: Antihistamines may cause excitability in children. Close monitoring for adverse reactions is recommended.
Special Cases:
- Elderly Patients: Start with a lower dose and titrate upwards as needed, monitoring for side effects.
- Patients with Renal Impairment: Dosage adjustments may be necessary. Consult specialized resources for specific recommendations based on the degree of impairment.
- Patients with Hepatic Dysfunction: Use with caution; dose reduction may be necessary.
- Patients with Comorbid Conditions: Consider individual patient factors, including other medications and existing medical conditions, when determining dosage.
Clinical Use Cases The specific combination of chlorpheniramine maleate, dextromethorphan hydrobromide, and guaifenesin is generally not indicated for use in clinical settings like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. In these situations, specific and tailored therapies are preferred over this combination.
Dosage Adjustments Dosage modifications are based on individual patient characteristics. Factors such as age, weight, renal function, hepatic function, and concomitant medications must be considered.
Side Effects
Common Side Effects
- Drowsiness
- Dizziness
- Dry mouth, nose, and throat
- Nausea and vomiting
- Headache
Rare but Serious Side Effects
- Allergic reactions (e.g., rash, itching, swelling, severe dizziness, difficulty breathing)
- Seizures
- Confusion
- Hallucinations
Long-Term Effects
Chronic complications from prolonged use are rare but can include tolerance to the cough suppressant effects of dextromethorphan.
Adverse Drug Reactions (ADR)
Serious ADRs, though rare, require immediate medical attention. These can include severe allergic reactions, respiratory depression, and cardiac arrhythmias.
Contraindications
- Hypersensitivity to any component of the medication
- Narrow-angle glaucoma, urinary retention, peptic ulcer
- Asthma attack
- Concurrent or recent use of monoamine oxidase inhibitors (MAOIs)
Drug Interactions
- MAOIs (serious interaction risk)
- Alcohol (increased central nervous system depression)
- Other medications that cause drowsiness (additive effect)
- Anticholinergic drugs (additive anticholinergic effects)
Pregnancy and Breastfeeding
- Pregnancy Safety Category: Category C (animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks).
- Fetal Risks: Increased risk of inguinal hernias in neonates has been reported with guaifenesin.
- Drug Excretion in Breast Milk: It is unknown if these drugs are excreted in human milk. Use with caution during breastfeeding.
Drug Profile Summary
- Mechanism of Action: Antihistamine, cough suppressant, and expectorant.
- Side Effects: Drowsiness, dizziness, dry mouth/nose/throat, nausea, vomiting, headache. Rarely: allergic reactions, seizures, confusion.
- Contraindications: Hypersensitivity, MAOI use, glaucoma, urinary retention, peptic ulcer, asthma attack.
- Drug Interactions: MAOIs, alcohol, other CNS depressants, anticholinergics.
- Pregnancy & Breastfeeding: Category C; use with caution if benefits outweigh risks.
- Dosage: Adults: 10 mL every 6 hours, not to exceed 4 doses/24 hours. Children (6-12 years): 5 mL every 6 hours, not to exceed 4 doses/24 hours. Adjustments may be needed for elderly, renal/hepatic impairment.
- Monitoring Parameters: Respiratory rate, mental status, allergic reactions.
Precautions
- General Precautions: Assess patient for allergies, pre-existing medical conditions (e.g., respiratory, hepatic, renal), and concomitant medications.
- Specific Populations: Caution in pregnancy and breastfeeding, children under 6, elderly patients.
- Lifestyle Considerations: Avoid alcohol, operating machinery.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Chlorpheniramine Maleate + Dextromethorphan Hydrobromide + Guaifenesin?
A: Adults: 10 mL every 6 hours, not to exceed 4 doses/24h. Children (6-12 years): 5 mL every 6 hours, not to exceed 4 doses/24h.
Q2: Can this medication be used in children under 6?
A: Not generally recommended unless specifically directed by a physician.
Q3: What are the common side effects?
A: Drowsiness, dizziness, dry mouth/nose/throat, nausea, vomiting, headache.
A: Allergic reactions (rash, itching, swelling, difficulty breathing), seizures, severe drowsiness, confusion.
Q5: Can I take this medicine with alcohol?
A: No, alcohol should be avoided as it can increase the risk of side effects like drowsiness and dizziness.
Q6: Is it safe to take this combination during pregnancy?
A: It’s a pregnancy Category C drug. Consult a doctor as it should only be used if the potential benefits outweigh the potential risks.
Q7: Can I breastfeed while taking this medication?
A: It’s unknown if the drug excretes in breastmilk. Consult a doctor.
Q8: What should I do if I miss a dose?
A: Take the missed dose as soon as you remember, unless it is close to the time for your next dose. Do not double the dose.
Q9: Can I operate machinery after taking this medication?
A: Caution is advised as this medication can cause drowsiness and affect alertness.
Q10: What are the main drug interactions to be aware of?
A: Avoid using with MAOIs. It can interact with alcohol, other CNS depressants, and anticholinergic drugs.
