Usage
- This drug is prescribed for the symptomatic relief of non-productive (dry) cough due to minor throat and bronchial irritation, often associated with the common cold or inhaled irritants. It provides a cooling sensation and soothes throat irritation.
- Pharmacological Classification: Antitussive (cough suppressant), expectorant, and topical anesthetic.
- Mechanism of Action: Dextromethorphan suppresses the cough reflex by acting on the cough center in the medulla oblongata within the brainstem. Menthol acts as a topical anesthetic, providing a cooling sensation that soothes throat irritation. Terpin hydrate acts as an expectorant, thinning mucus secretions in the airways and facilitating their expulsion.
Alternate Names
- There are no widely recognized alternate names for this specific combination. However, each ingredient can be referred to by their chemical names: Dextromethorphan hydrobromide, Menthol, and Terpin hydrate.
- Brand Names: Glycodin, Terp D, and various other generic formulations.
How It Works
- Pharmacodynamics: Dextromethorphan primarily affects the central nervous system by suppressing the cough reflex. Menthol exerts its effects locally in the throat, producing a cooling sensation and mild local anesthesia. Terpin hydrate works on the respiratory system, reducing the viscosity of mucus secretions.
- Pharmacokinetics:
- Absorption: Dextromethorphan is readily absorbed from the gastrointestinal tract. Menthol is absorbed through the mucous membranes of the mouth and throat. Terpin hydrate is absorbed from the gastrointestinal tract, though its absorption can be variable.
- Metabolism: Dextromethorphan is extensively metabolized in the liver, primarily by the cytochrome P450 2D6 (CYP2D6) enzyme. Menthol is metabolized in the liver. The metabolism of terpin hydrate is less well-characterized.
- Elimination: Dextromethorphan and its metabolites are primarily excreted in the urine. Menthol is excreted in the urine and bile. Terpin hydrate is primarily eliminated in the urine.
- Mode of Action: Dextromethorphan acts centrally on sigma-1 receptors and also has some activity at nicotinic acetylcholine receptors and serotonin and norepinephrine transporters in the brain. Menthol activates TRPM8 receptors, which are cold and menthol-sensitive receptors, leading to a cooling sensation. Terpin hydrate is thought to stimulate bronchial glands, resulting in increased fluid secretion and thinning of mucus.
Dosage
Standard Dosage
Adults:
- 10-20 mg orally every 4 hours, or 30 mg orally every 6-8 hours, not exceeding 120 mg in 24 hours.
Children:
- 4-6 years: 2.5-5 mg orally every 4 hours or 7.5 mg orally every 6-8 hours, not exceeding 30 mg in 24 hours.
- 6-12 years: 5-10 mg orally every 4 hours or 15 mg orally every 6-8 hours, not exceeding 60 mg in 24 hours.
- 12 years and above: Adult dosage.
- Pediatric Safety Considerations: Use with caution in children under 4 years old; not generally recommended.
Special Cases:
- Elderly Patients: Dosage adjustment may be necessary based on renal and hepatic function. Start at the lower end of the dosage range.
- Patients with Renal Impairment: Caution is advised; dosage adjustment may be necessary.
- Patients with Hepatic Dysfunction: Caution is advised; dosage adjustment may be necessary.
- Patients with Comorbid Conditions: Use with caution in patients with asthma, chronic bronchitis, or emphysema.
Clinical Use Cases
The combination of dextromethorphan, menthol, and terpin hydrate is typically used for the management of dry cough in outpatient settings. The dosages provided above apply to such scenarios. This combination is not typically utilized in clinical settings like intubation, surgical procedures, mechanical ventilation, or the ICU. In emergency situations, other medications are generally preferred.
Dosage Adjustments
Dose adjustments are advised in patients with renal or hepatic impairment. Consult a healthcare professional for specific recommendations based on the individual patient’s condition.
Side Effects
Common Side Effects
- Nausea
- Vomiting
- Stomach pain
- Dizziness
- Rash
- Confusion
Rare but Serious Side Effects
- Allergic reactions (e.g., difficulty breathing, swelling of the face, lips, tongue, or throat)
- Hallucinations
- Serotonin syndrome (rare but serious with higher doses or interactions with other serotonergic drugs)
Long-Term Effects
Long-term use of this combination is generally not recommended due to the limited evidence on its safety.
Adverse Drug Reactions (ADR)
Clinically significant ADRs are rare but may include severe allergic reactions and serotonin syndrome.
Contraindications
- Hypersensitivity to any of the ingredients
- Concurrent use of MAO inhibitors (or within 14 days of discontinuing MAOIs)
- Severe liver disease
Drug Interactions
- MAO inhibitors
- Serotonergic drugs (e.g., SSRIs, SNRIs, tricyclic antidepressants)
- Alcohol
- Other CNS depressants (e.g., benzodiazepines, opioids)
Pregnancy and Breastfeeding
- Pregnancy Safety Category: C (consult a doctor before use; benefits should outweigh risks)
- Limited data are available on the use of this combination during pregnancy. Consult a doctor before use.
- Breastfeeding: Dextromethorphan and menthol are excreted in breast milk in small amounts. Exercise caution when using during breastfeeding.
Drug Profile Summary
- Mechanism of Action: See “How It Works” above.
- Side Effects: See “Side Effects” above.
- Contraindications: See “Contraindications” above.
- Drug Interactions: See “Drug Interactions” above.
- Pregnancy & Breastfeeding: See “Pregnancy and Breastfeeding” above.
- Dosage: See “Dosage” above.
- Monitoring Parameters: Monitor for respiratory status, CNS effects, and allergic reactions.
Popular Combinations
This combination itself is a popular combination and is not usually combined with other active pharmaceutical ingredients. However, related combination products might exist that include additional components like guaifenesin or antihistamines for broader symptom relief.
Precautions
- General Precautions: Assess for allergies to the ingredients. Caution in patients with hepatic or renal impairment, respiratory conditions (asthma, chronic bronchitis, emphysema), and cardiovascular disease.
- Specific Populations: See “Dosage - Special Cases” and “Pregnancy and Breastfeeding.”
- Lifestyle Considerations: Avoid alcohol while taking this medication. May cause drowsiness, which could impair driving or operating machinery.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Dextromethorphan Hydrobromide + Menthol + Terpin Hydrate?
A: See “Dosage” above for detailed information.
Q2: Can this medication be used in children under 4 years old?
A: Use in children under 4 years old is generally not recommended. Consult a pediatrician.
Q3: What are the common side effects of this medication?
A: Common side effects include nausea, vomiting, dizziness, rash, and confusion.
Q4: Can pregnant or breastfeeding women take this medication?
A: Consult a doctor before use during pregnancy or breastfeeding. Limited data are available, and the benefits should outweigh the risks.
Q5: Does this medication interact with any other drugs?
A: Yes, it can interact with MAO inhibitors, serotonergic drugs, alcohol, and other CNS depressants.
Q6: What is the mechanism of action of this medication?
A: Dextromethorphan suppresses the cough reflex, menthol acts as a topical anesthetic, and terpin hydrate thins mucus secretions.
Q7: How long can I take this medication?
A: Use for the shortest duration necessary to relieve symptoms. Consult a healthcare professional if symptoms persist beyond 7 days.
Q8: Are there any contraindications to using this medication?
A: Yes, contraindications include hypersensitivity to the ingredients, concurrent use of MAO inhibitors, and severe liver disease.
Q9: Can I drive or operate machinery while taking this medication?
A: Use caution, as the medication may cause drowsiness, which could impair your ability to drive or operate machinery.
Q10: What should I do if I experience any side effects?
A: If you experience any bothersome side effects, consult a healthcare professional.
