Usage
This combination medication is primarily used for the short-term relief of symptoms associated with the common cold, allergies, and the flu, such as:
- Runny nose
- Sneezing
- Itchy or watery eyes
- Nasal congestion
- Cough
Pharmacological Classifications:
- Chlorpheniramine & Diphenhydramine: First-generation antihistamines
- Phenylephrine: Decongestant (sympathomimetic amine)
- Menthol: Topical analgesic and counterirritant
Mechanism of Action:
- Chlorpheniramine and Diphenhydramine block the action of histamine, reducing allergic symptoms.
- Phenylephrine constricts blood vessels in the nasal passages, relieving congestion.
- Menthol provides a cooling sensation and soothes irritated throat tissues.
Alternate Names
This specific combination may not have a universally recognized non-proprietary name. It’s generally referred to by its component drugs. Brand names vary depending on the manufacturer and region. Some examples include (but are not limited to):
Sinarest AF Jr. syrup (contains Phenylephrine Hydrochloride 5 mg, Chlorpheniramine Maleate 1 mg, Sodium Citrate 60 mg, and menthol)
How It Works
Pharmacodynamics:
- Antihistamines: Chlorpheniramine and Diphenhydramine competitively antagonize H1 histamine receptors, reducing the effects of histamine release.
- Decongestant: Phenylephrine acts as an alpha-1 adrenergic receptor agonist, causing vasoconstriction in the nasal mucosa.
- Menthol: Stimulates cold receptors, creating a cooling sensation and reducing throat irritation.
Pharmacokinetics:
- Absorption: All components are absorbed orally.
- Metabolism: Primarily hepatic metabolism for all components.
- Elimination: Primarily renal excretion.
Mode of Action:
- Chlorpheniramine/Diphenhydramine: Blocks histamine from binding to H1 receptors, reducing vasodilation, capillary permeability, and mucus secretion.
- Phenylephrine: Activates alpha-1 adrenergic receptors, constricting arterioles and reducing nasal blood flow.
- Menthol: Activates TRPM8 receptors (transient receptor potential cation channel subfamily M member 8), producing a cooling sensation.
Dosage
Standard Dosage
Adults:
Dosage varies based on the specific product formulation. Refer to the manufacturer’s instructions. As a general guide, for a combination containing Phenylephrine Hydrochloride 5 mg, Chlorpheniramine Maleate 1 mg, Sodium Citrate 60 mg, and menthol (e.g., Sinarest AF Jr. syrup, although this is marketed for children): 10-15 mL three to four times a day.
Children:
Dosage depends on age and specific formulation. Always consult the manufacturer’s guidelines. For the example above (Sinarest AF Jr.): 2-5 years: 5ml three/four times a day; 6-12 years: 10ml three/four times a day.
Pediatric Safety Considerations:
Use with caution in children. Antihistamines can cause paradoxical excitation in young children.
Special Cases:
Elderly Patients: Start with a lower dose and monitor closely for adverse effects.
Patients with Renal Impairment: Dose adjustment may be needed.
Patients with Hepatic Dysfunction: Dose adjustment may be necessary.
Patients with Comorbid Conditions: Caution is advised in patients with cardiovascular disease, hypertension, hyperthyroidism, diabetes, and closed-angle glaucoma.
Clinical Use Cases
This combination is not typically used in clinical settings like intubation, surgical procedures, mechanical ventilation, or the ICU.
Dosage Adjustments
Adjustments may be necessary for renal or hepatic impairment. Consult specific product information.
Side Effects
Common Side Effects:
- Drowsiness
- Dry mouth
- Blurred vision
- Constipation
- Urinary retention
Rare but Serious Side Effects:
- Allergic reactions (rash, itching, swelling)
- Cardiac arrhythmias
- Seizures
Long-Term Effects
Prolonged use of decongestants can lead to rebound congestion. Avoid using for more than a few days.
Adverse Drug Reactions (ADR)
Severe allergic reactions, cardiac effects, and neurological effects require immediate medical attention.
Contraindications
- Hypersensitivity to any of the components
- Severe hypertension or coronary artery disease
- Monoamine oxidase inhibitor (MAOI) use
- Narrow-angle glaucoma
- Urinary retention
Drug Interactions
- MAOIs
- Tricyclic antidepressants
- Other antihistamines or decongestants
- Alcohol
- Sedatives
Pregnancy and Breastfeeding
Consult a doctor before use during pregnancy or breastfeeding. Avoid if possible as safety hasn’t been thoroughly established, and consider alternative medications.
Drug Profile Summary
- Mechanism of Action: Combination of antihistamine, decongestant, analgesic, and counterirritant actions
- Side Effects: Drowsiness, dry mouth, blurred vision, constipation, urinary retention. Rarely: allergic reactions, cardiac arrhythmias, seizures
- Contraindications: Hypersensitivity, severe hypertension/CAD, MAOI use, narrow-angle glaucoma, urinary retention
- Drug Interactions: MAOIs, tricyclic antidepressants, other antihistamines/decongestants, alcohol, sedatives
- Pregnancy & Breastfeeding: Consult a doctor before use
- Dosage: Varies by product. Refer to the manufacturer’s instructions.
- Monitoring Parameters: Blood pressure, heart rate, respiratory rate
Popular Combinations
Often combined with other cold and flu medications, but must be done with care due to potential ingredient overlap.
Precautions
Standard precautions for allergy, liver or kidney conditions. Exercise caution in pregnant/breastfeeding women, children, and the elderly. Avoid alcohol and operating machinery.
FAQs
Q1: What is the recommended dosage for Chlorpheniramine Maleate + Diphenhydramine + Menthol + Phenylephrine?
A: The dosage varies depending on the product. A doctor or pharmacist can help guide as to a specific product.
Q2: Can I take this medication if I am pregnant or breastfeeding?
A: Consult a doctor before use during pregnancy or breastfeeding.
Q3: What are the common side effects?
A: Drowsiness, dry mouth, blurred vision, constipation, and urinary retention are common side effects.
Q4: Are there any serious side effects I should be aware of?
A: Rare but serious side effects include allergic reactions, cardiac arrhythmias, and seizures.
Q5: Can I drive or operate machinery while taking this medication?
A: Avoid driving or operating machinery as the medication can cause drowsiness.
Q6: What should I do if I miss a dose?
A: Take the missed dose as soon as you remember, unless it is almost time for your next dose. Do not double the dose.
Q7: Can I take this medication with other over-the-counter cold remedies?
A: Consult a doctor or pharmacist before combining with other medications, especially those containing antihistamines or decongestants.
Q8: How long can I take this medication?
A: For short-term relief only. Avoid using for more than a few days, especially decongestants due to the risk of rebound congestion.
Q9: Is it safe to take this medication with alcohol?
A: Avoid alcohol while taking this medication. It can increase drowsiness and other side effects.
