Usage
This combination medication is used to treat symptoms associated with the common cold, flu, and other upper respiratory infections. It targets cough, nasal congestion, and minor throat irritation. These combined ingredients address multiple symptoms simultaneously.
It’s pharmacological classifications include:
- Antitussive: Dextromethorphan suppresses cough by acting on the cough center in the brain.
- Decongestant: Phenylephrine constricts blood vessels in the nasal passages, reducing swelling and congestion.
- Expectorant: Ammonium chloride helps to loosen and thin mucus, making it easier to cough up.
- Topical Anesthetic: Menthol provides a cooling sensation that soothes minor throat irritation.
Alternate Names
This specific combination may not have a universally recognized international non-proprietary name (INN). The individual components, however, do have their own INNs. This combination is often described by its constituent drugs. Brand names may vary depending on the manufacturer and region. Some common brand names include Piritexyl Cough Syrup.
How It Works
Pharmacodynamics:
- Dextromethorphan: Acts centrally on the medulla oblongata to suppress the cough reflex.
- Phenylephrine: An alpha-adrenergic agonist, causing vasoconstriction in the nasal mucosa, reducing congestion.
- Ammonium chloride: Increases respiratory tract fluid secretions, reducing mucus viscosity and aiding expectoration.
- Menthol: Activates TRPM8 receptors in the throat, creating a cooling sensation and relieving minor irritation.
Pharmacokinetics:
- Absorption: All components are absorbed orally, although at varying rates.
- Metabolism: Dextromethorphan is primarily metabolized in the liver by CYP2D6 and CYP3A4 enzymes. Phenylephrine undergoes first-pass metabolism, and ammonium chloride is partially metabolized. Menthol is extensively metabolized.
- Elimination: Primarily through renal excretion, with some hepatic elimination for certain components.
Dosage
Standard Dosage
Adults: The usual dose is 5 mL (1 teaspoonful) every 4 to 6 hours, not to exceed 30 mL (6 teaspoonfuls) in 24 hours.
Children: Dosage for children under 12 years old should be determined based on the child’s weight and age, and administered under strict medical supervision.
Special Cases:
- Elderly Patients: Start with a lower dose and monitor closely for adverse effects. Dose adjustments may be necessary based on renal function and other comorbid conditions.
- Patients with Renal Impairment: Dosage adjustment is required based on the degree of impairment. Consult resources for drug dosing in renal impairment.
- Patients with Hepatic Dysfunction: Use with caution in patients with severe hepatic impairment. Dosage adjustments might be necessary.
- Patients with Comorbid Conditions: Caution is advised in patients with hypertension, heart disease, asthma, hyperthyroidism, glaucoma, diabetes mellitus, and prostatic hypertrophy.
Clinical Use Cases This medication is primarily indicated for symptomatic relief of cough and congestion associated with common cold or flu. It is not typically used in clinical settings like intubation, surgical procedures, mechanical ventilation, ICU, or emergency situations.
Side Effects
Common Side Effects
Nausea, vomiting, dry mouth, stomach upset, headache, restlessness, dizziness, drowsiness.
Rare but Serious Side Effects
Allergic reactions (rash, itching, swelling), difficulty breathing, hallucinations, rapid or irregular heartbeat.
Long-Term Effects
Chronic use of phenylephrine can lead to rebound congestion. Long-term use of dextromethorphan at high doses can rarely cause neurological problems.
Adverse Drug Reactions (ADR) Serious ADRs include severe allergic reactions, cardiac arrhythmias, and serotonin syndrome (with MAOI interaction).
Contraindications
Hypersensitivity to any of the components, severe hypertension, severe coronary artery disease, concurrent or recent use of monoamine oxidase inhibitors (MAOIs), narrow-angle glaucoma, urinary retention, peptic ulcer, asthma attack.
Drug Interactions
MAOIs, alcohol, other CNS depressants (e.g., sedatives, hypnotics, opioids), tricyclic antidepressants, beta-blockers, antihypertensives, certain antidepressants (e.g., SSRIs).
Pregnancy and Breastfeeding
The safety of this combination during pregnancy and breastfeeding has not been fully established. Use only if clearly needed and after careful consideration of risks and benefits. Phenylephrine may decrease milk production.
Drug Profile Summary
- Mechanism of Action: Combines antitussive, decongestant, expectorant, and topical anesthetic actions.
- Side Effects: Nausea, vomiting, dry mouth, dizziness, drowsiness, rare but serious allergic reactions, cardiac issues.
- Contraindications: Hypersensitivity, MAOI use, severe cardiovascular disease, glaucoma, urinary retention.
- Drug Interactions: MAOIs, CNS depressants, tricyclic antidepressants, beta-blockers.
- Pregnancy & Breastfeeding: Consult a doctor before use; safety not fully established.
- Dosage: Adults: 5 mL every 4-6 hours, not to exceed 30 mL in 24 hours. Pediatric and special population dosing should be carefully determined.
- Monitoring Parameters: Blood pressure, heart rate, respiratory rate, mental status.
Popular Combinations
While this combination itself is common, additional ingredients are sometimes included, such as guaifenesin (another expectorant) or chlorpheniramine (an antihistamine).
Precautions
Assess for pre-existing conditions, allergies, and concomitant medications. Caution in patients with cardiovascular disease, respiratory issues, and other chronic illnesses. Avoid alcohol and other CNS depressants. Advise against driving or operating heavy machinery until effects are known.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Ammonium Chloride + Dextromethorphan Hydrobromide + Menthol + Phenylephrine?
A: Adults: 5 mL (1 teaspoonful) every 4 to 6 hours, not to exceed 30 mL (6 teaspoonfuls) in 24 hours. Children: Consult a doctor.
Q2: Can this combination be used in patients with hypertension?
A: Use with caution and monitor blood pressure.
Q3: Is it safe to take this medication while pregnant or breastfeeding?
A: Consult a doctor before use; safety not established.
Q4: What are the common side effects?
A: Nausea, vomiting, dry mouth, dizziness, drowsiness.
Q5: Can this be taken with other cold medications?
A: Consult a doctor before combining with other medications, especially other CNS depressants or MAOIs.
Q6: Can a patient operate machinery after taking this medication?
A: Advise against driving or operating machinery until effects are known, due to potential drowsiness or dizziness.
Q7: What should be done in case of an overdose?
A: Seek immediate medical attention.
Q8: How long should this medication be taken?
A: Take as directed by a physician. Generally, for short-term symptomatic relief.
Q9: Can this medicine be used with MAOI?
A: Absolutely contraindicated with MAOIs.
