Usage
Dextromethorphan Hydrobromide + Phenylpropanolamine is prescribed for the relief of cough, nasal congestion, and other symptoms associated with the common cold, flu, allergies, and other upper respiratory tract infections.
Pharmacological Classification:
- Dextromethorphan Hydrobromide: Antitussive (cough suppressant)
- Phenylpropanolamine Hydrochloride: Nasal decongestant
Mechanism of Action:
- Dextromethorphan Hydrobromide: Suppresses the cough reflex by acting on the cough center in the medulla oblongata within the brainstem.
- Phenylpropanolamine Hydrochloride: Acts as a sympathomimetic amine, constricting blood vessels in the nasal mucosa, reducing swelling and congestion.
Alternate Names
There is no officially recognized single alternate name for this specific combination. The individual components may be referred to as follows:
- Dextromethorphan HBr: D-Methorphan, DXM, Dextromethorphan hydrobromide
- Phenylpropanolamine HCl: PPA, Phenylpropanolamine hydrochloride
Brand Names: Several brand names market this combination, often with additional ingredients like paracetamol (acetaminophen) or guaifenesin. Examples include Tuseran Forte and Decolsin.
How It Works
Pharmacodynamics:
- Dextromethorphan: Acts centrally within the brain to suppress the cough reflex without affecting respiratory secretions. It does not have analgesic (pain-relieving) or addictive properties like opioid cough suppressants.
- Phenylpropanolamine: Produces vasoconstriction in the nasal passages by stimulating alpha-adrenergic receptors, thus relieving congestion. It can also have mild stimulant effects on the central nervous system.
Pharmacokinetics:
- Dextromethorphan: Well-absorbed orally. Extensively metabolized in the liver, primarily by CYP2D6, into dextrorphan and other metabolites. Excreted in the urine.
- Phenylpropanolamine: Readily absorbed from the gastrointestinal tract. Metabolized in the liver. Eliminated primarily through renal excretion.
Mode of Action:
- Dextromethorphan: Binds to sigma-1 receptors and, to a lesser extent, NMDA receptors in the central nervous system, suppressing the cough reflex.
- Phenylpropanolamine: Stimulates alpha-adrenergic receptors on vascular smooth muscle, causing vasoconstriction.
Elimination Pathways:
- Dextromethorphan: Primarily renal excretion of metabolites.
- Phenylpropanolamine: Primarily renal excretion.
Dosage
It is important to note that phenylpropanolamine has been associated with an increased risk of hemorrhagic stroke and is no longer available in many countries. Therefore, the following dosage information is based on product information where it is still available and should only be considered in consultation with a doctor where it remains authorized:
Standard Dosage
Adults:
- Capsule: One capsule every 6 hours (consult specific product information for exact strengths).
- Suspension: 10 mL every 6 hours.
Children:
Dosage is dependent on the formulation and should be carefully reviewed based on specific product instructions, weight, and age. General guidelines (where available) are:
- 2-6 years: 2.5 mL of suspension every 6 hours.
- 7-12 years: 5 mL of suspension every 6 hours.
Special Cases:
The use of this combination is generally avoided in special populations (elderly, renal/hepatic impairment) given the risks associated with phenylpropanolamine. Consult a physician if considering use in these patients.
Clinical Use Cases
This combination drug is not indicated for use in clinical settings such as intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. Its use is limited to the relief of cough and cold symptoms.
Dosage Adjustments
Dosage adjustments are usually not recommended due to the risks of phenylpropanolamine. The use of this drug should be avoided in patients with renal or hepatic impairment.
Side Effects
Common Side Effects:
- Dizziness
- Drowsiness
- Nausea
- Vomiting
- Headache
- Restlessness
- Insomnia
- Tremors
Rare but Serious Side Effects:
- Allergic reactions (rash, itching, swelling)
- Hallucinations
- Seizures
- Hypertensive crisis
- Stroke
Long-Term Effects:
Limited data are available on the long-term effects.
Adverse Drug Reactions (ADR):
Severe allergic reactions, stroke, hypertensive crisis, and cardiac arrhythmias.
Contraindications
- Hypersensitivity to dextromethorphan or phenylpropanolamine
- Severe cardiovascular disease (including hypertension)
- Hyperthyroidism
- Glaucoma
- Concomitant use of MAOIs
- Use within 14 days of MAOI discontinuation
Drug Interactions
- MAOIs: Can lead to hypertensive crisis.
- Antidepressants: May interact with phenylpropanolamine.
- Other medications with sympathomimetic effects: Can potentiate cardiovascular effects.
Pregnancy and Breastfeeding
Phenylpropanolamine should be avoided during pregnancy due to potential risks. Dextromethorphan use should be discussed with a physician to assess the benefit versus risk. The safety during breastfeeding is not fully established for either drug; therefore, the combination is best avoided.
Drug Profile Summary
- Mechanism of Action: Dextromethorphan suppresses cough centrally; phenylpropanolamine causes nasal vasoconstriction.
- Side Effects: Dizziness, drowsiness, nausea, headache, potential for serious cardiovascular effects.
- Contraindications: Hypersensitivity, cardiovascular disease, hyperthyroidism, MAOI use.
- Drug Interactions: MAOIs, antidepressants, sympathomimetics.
- Pregnancy & Breastfeeding: Generally avoided.
- Dosage: Varies by product and age; see above.
- Monitoring Parameters: Blood pressure, heart rate.
Popular Combinations
This combination is sometimes found with paracetamol or guaifenesin in some products.
Precautions
This medication should be used cautiously in individuals with:
- Hypertension
- Cardiovascular disease
- Diabetes
- Asthma
- BPH
- Glaucoma
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Dextromethorphan Hydrobromide + Phenylpropanolamine?
A: The dosage varies depending on the product and the patient’s age. See detailed information above. It’s crucial to consult with a physician or review the specific product labeling.
Q2: Is this combination safe for use during pregnancy or while breastfeeding?
A: No, it is generally recommended to avoid this combination during pregnancy and breastfeeding due to potential risks associated with phenylpropanolamine.
Q3: What are the serious side effects to watch out for?
A: Serious side effects include allergic reactions, hypertension, stroke, heart rhythm problems, and seizures. Seek immediate medical attention if these occur.
Q4: Can I operate machinery while taking this medication?
A: Caution is advised as this combination can cause drowsiness and dizziness, which may impair the ability to operate machinery safely.
Q5: 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 scheduled dose. Do not double the dose.
Q6: Can I take this with other over-the-counter cold and cough medications?
A: It is not recommended to take this combination with other products containing dextromethorphan, phenylpropanolamine, paracetamol (acetaminophen) or other sympathomimetics, without consulting a doctor.
Q7: What are the main contraindications for this combination?
A: Contraindications include hypersensitivity, severe cardiovascular disease, hyperthyroidism, MAOI use, and glaucoma.
Q8: How does this combination interact with MAOIs?
A: Co-administration with MAOIs can precipitate a hypertensive crisis and is therefore contraindicated.
Q9: What are the symptoms of an overdose?
A: Overdose symptoms can include rapid heart rate, elevated blood pressure, hallucinations, confusion, and seizures. Immediate medical attention is required.
