Dextrim

Uses

This preparation is used for the symptomatic relief of upper respiratory tract disorders accompanied by non-productive cough which benefits from the administration of a nasal decongestant, a histamine H1-receptor antagonist and an antitussive combination.

Dextrim 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 antisepsisAllergic Rhinitis (AR), Anorectal discomfort, Cold, Common Cold, Common Cold/Flu, Congestion of the Conjunctivas, Conjunctivitis allergic, Cough, Cough caused by Common Cold, Eye allergy, Eye redness, Fever, Flu caused by Influenza, Headache, Headache caused by Allergies, Headache caused by Common Cold, Headache caused by Pollen Allergy, Hemorrhoids, Hypotension, Irritative cough, Itching of the nose, Itching of the throat, Laryngotracheitis, Nasal Congestion, Nose discomfort, Ocular Inflammation, Ocular Irritation, Paroxysmal Supraventricular Tachycardia, Pollen Allergy, Respiratory tract congestion, Respiratory tract irritation, Rhinopharyngitis, Rhinorrhoea, Seasonal Allergies, Shock, Cardiogenic, Sinus Congestion, Sinus pressure, Sinusitis, Sneezing, Sore Throat, Tracheobronchitis, Upper respiratory tract hypersensitivity reaction, site unspecified, Vasomotor Rhinitis, Aching caused by Flu caused by Influenza, Bronchial congestion, Itchy throat, Minor aches and pains, Watery itchy eyes, Airway secretion clearance therapy, Antihistamine, Dilatation of the pupil, Vasoconstrictor in regional analgesia therapyNasal Congestion, Perennial Allergic Rhinitis (PAR), Seasonal Allergic Conjunctivitis, Seasonal Allergic Rhinitis, Upper respiratory tract signs and symptoms, Vasomotor Rhinitis, Mild Angioedema, Mild urticaria, Upper respiratory discomfort

How Dextrim works

Dextromethorphan 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.

Phenylephrine is an alpha-1 adrenergic agonist that mediates vasoconstriction and mydriasis depending on the route and location of administration. Systemic exposure to phenylephrine also leads to agonism of alpha-1 adrenergic receptors, raising systolic and diastolic pressure as well as peripheral vascular resistance. Increased blood pressure stimulates the vagus nerve, causing reflex bradycardia.

Triprolidine binds to the histamine H1 receptor. This blocks the action of endogenous histamine, which subsequently leads to temporary relief of the negative symptoms brought on by histamine.

Dosage

Dextrim dosage

Adults & Children over 12 years: 1 teaspoonful 4 times a day.

6-12 years: 1/2 teaspoonful 4 times a day.

A physician's advice should be obtained before administering this combination to children less than 6 years.

Take with or without food. Take with food if it causes an upset stomach. Measure liquid doses carefully. Use the measuring device that comes with this medicine.

Side Effects

Side effects of Dextromethorphan appears to be rare and may include drowsiness. Prostatic enlargement could have been an important predisposing factor.

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.

Patients experiencing and overdose may present with headache, hypertension, reflex bradycardia, tingling limbs, cardiac arrhythmias, and a feeling of fullness in the head. Overdose may be treated by supportive care and discontinuing phenylephrine, chronotropic medications, and vasodilators. Subcutaneous phentolamine may be used to treat tissue extravasation.

Symptoms of overdose include drowsiness, weakness, inco-ordination, difficulty with micturition, respiratory depression, hypotension, agitation, irritability, convulsions, hypertension, palpitation and tachycardia.

Precaution

This combination may cause drowsiness. It may impair the patient’s ability to drive and also to use machineries. Although there are no objective data, users of this syrup should avoid the concomitant use of alcohol or other centrally acting sedatives. As with other sympathomimetic agents caution should be exercised in patients with hypertension, heart disease, diabetes, hyperthyroidism, elevated intraocular pressure and prostatic enlargement. This combination should not be used for persistent or chronic cough such as occurs with smoking, asthma, or emphysema or where cough is accompanied by excessive secretion unless directed by a physician.

Interaction

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

Volume of Distribution

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

The volume of distribution of phenylephrine is 340L.

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.

Phenylephrine is 38% orally bioavailable. Clinically significant systemic absorption of ophthalmic formulations is possible, especially at higher strengths and when the cornea is damaged.

Rapidly absorbed in the intestinal tract.

Half Life

Dextromethorphan has a half life of 3-30 hours.

Intravenous phenylephrine has an effective half life of 5 minutes and an elimination half life of 2.5 hours.

4 to 6 hours.

Clearance

Phenylephrine has an average clearance of 2100mL/min.

Elimination Route

86% of a dose of phenylephrine is recovered in the urine with 16% as the unmetabolized drug, 57% as the inactive meta-hydroxymendelic acid, and 8% as inactive sulfate conjugates.

Pregnancy & Breastfeeding use

There are no specific data on use of this combination during pregnancy & lactation

Contraindication

This combination is contraindicated in patients with a known hypersensitivity to Dextromethorphan, Phenylephrine or Triprolidine as well as in persons under treatment with Monoamine Oxidase Inhibitor within 2 weeks of stopping such treatment.

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

Protect from light, store in a cool and dry place. Keep out of the reach of children.

Innovators Monograph

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