D-methorphan

Uses

D-methorphan is used for Chronic dry cough or unproductive cough; Acute dry cough which is interfering with normal function or sleep.

D-methorphan is also used to associated treatment for these conditions: Allergic cough, Common Cold, Common Cold/Flu, Cough, Cough caused by Common Cold, Coughing caused by Allergies, Coughing caused by Bronchitis, Coughing caused by Flu caused by Influenza, Fever, Flu caused by Influenza, Headache, Irritative cough, Itching of the nose, Itching of the throat, Nasal Congestion, Pseudobulbar affect, Rhinorrhoea, Sneezing, Upper respiratory symptoms, Watery itchy eyes, Airway secretion clearance therapy, Bronchodilation, Oropharyngeal antisepsis

How D-methorphan works

D-methorphan is an agonist of NMDA and sigma-1 receptors. It is also an antagonist of α3/β4 nicotinic receptors.[A10589] However, the mechanism by which dextromethorphan's receptor agonism and antagonism translates to a clinical effect is not well understood.

Dosage

D-methorphan dosage

Adults and Children over 12 years: 15 to 30 mg three to four times per day. However, 60 mg doses up to four times per day have been used without increased side effects.

Children between 6 and 12 years: 5-15 mg up to four times per day.

Children between 2 and 6 years: 2.5-5 mg up to four times per day.

Side Effects

Adverse effects with D-methorphan are rare, but nausea and dizziness sometimes occur. The drug produces no analgesia or addiction and little or no CNS depression. Excitation, confusion and respiratory depression may occur after overdosage.

Toxicity

A dextromethorphan overdose may present as nausea, vomiting, stupor, coma, respiratory depression, seizures, tachycardia, hyperexcitability, toxic psychosis, ataxia, nystagmus, dystonia, blurred vision, changes in muscle reflexes, and serotonin syndrome. Overdose should be managed through symptomatic and supportive measures.

Precaution

Do not use D-methorphan to control a cough that is associated with smoking, asthma, or emphysema, or a cough that is productive (produces sputum or phlegm).

Interaction

The following medicines should be taken carefully while concomitantly use with D-methorphan: Amiodarone, Fluoexetine, Quinidine, CNS depressants and Monoamine oxidase (MAO) inhibitors.

Food Interaction

• Take with or without food. The absorption is unaffected by food.

D-methorphan Alcohol interaction

[Moderate] GENERALLY AVOID:

The central nervous system-depressant effects of dextromethorphan and ethanol may be additive.

The combination of these agents may result in additive CNS depression and impairment of judgment, thinking, and psychomotor skills.

Patients should be cautioned about the concomitant ingestion of dextromethorphan and ethanol.

Consumption of large doses of either substance should be avoided.

D-methorphan Drug Interaction

Moderate: diphenhydramine, diphenhydramine, alprazolam, alprazolamUnknown: omega-3 polyunsaturated fatty acids, omega-3 polyunsaturated fatty acids, fluticasone nasal, fluticasone nasal, guaifenesin, guaifenesin, acetaminophen, acetaminophen, cyanocobalamin, cyanocobalamin, ascorbic acid, ascorbic acid, cholecalciferol, cholecalciferol, cetirizine, cetirizine

D-methorphan Disease Interaction

Moderate: psychiatric conditions

Volume of Distribution

The volume of distribution of dextromethorphan is 5-6.7L/kg.

Elimination Route

A 30mg oral dose of dextromethorphan reaches a C_max of 2.9 ng/mL, with a T_max of 2.86 h, and an AUC of 17.8 ng*h/mL.

Half Life

D-methorphan has a half life of 3-30 hours.

Pregnancy & Breastfeeding use

Pregnancy: Adequate and well-controlled studies in human have not been done. However, D-methorphan has not been reported to cause birth defects.

Lactation: It is not known whether dextromethorphan passes into breast milk. However, D-methorphan has not been reported to cause problems in nursing babies.

Contraindication

Hypersensitivity to D-methorphan or any other component.

Acute Overdose

Symptoms: In mild overdose, tachycardia, hypertension, vomiting, mydriasis, diaphoresis, nystagmus, euphoria, loss of motor coordination, and giggling; in moderate intoxication, in addition to those listed above, hallucinations and a plodding ataxic gait; in severely intoxication, agitation or somnolence.

Management: treatment is symptomatic and supportive. Naloxone may be useful in reversing toxicity.

Storage Condition

Store at 15-30° C

Innovators Monograph

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