Zenrid D

Uses

Levocetirizine Dihydrochloride is used for the treatment of symptoms associated with allergic conditions such as seasonal allergic rhinitis, perennial allergic rhinitis and chronic idiopathic urticaria.

Phenylephrine is an alpha-1 adrenergic agonist used in the management of hypotension, generally in the surgical setting associated with the use of anesthetics.

Phenylephrine injections are indicated to treat hypotension caused by shock or anesthesia, an ophthalmic formulation is indicated to dilate pupils and induce vasoconstriction, an intranasal formulation is used to treat congestion, and a topical formulation is used to treat hemorrhoids. Off-label uses include situations that require local blood flow restriction such as the treatment of priapism.

Zenrid D is also used to associated treatment for these conditions: Allergic Rhinitis (AR), Chronic Idiopathic Urticaria, Common Cold, Nasal Congestion, Perennial Allergic Rhinitis (PAR), Seasonal Allergic RhinitisAllergic 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 therapy

How Zenrid D works

Levocetirizine selectively inhibits histamine H₁ receptors. This action prevents histamine from activating this receptor and causing effects like smooth muscle contraction, increased permeability of vascular endothelium, histidine uptake in basophils, stimulation of cough receptors, and stimulation of flare responses in the nervous system.

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.

Dosage

Zenrid D dosage

Adults and children 12 years of age and older: 5 mg once daily in the evening

Children 6 to 11 years of age: 2.5 mg once daily in the evening

Children 6 months to 5 years of age: 1.25 mg (1/2 teaspoon oral solution) once daily in the evening

Renal Impairment: Adjust the dose in patients 12 years of age and older with decreased renal function

Side Effects

The most common adverse reactions (rate ≥2% and > placebo) were somnolence, nasopharyngitis, fatigue, dry mouth, and pharyngitis in subjects 12 years of age and older, and pyrexia, somnolence, cough, and epistaxis in children 6 to 12 years of age. In subjects 1 to 5 years of age, the most common adverse reactions (rate ≥2% and > placebo) were pyrexia, diarrhea, vomiting, and otitis media. In subjects 6 to 11 months of age, the most common adverse reactions (rate ≥3% and > placebo) were diarrhea and constipation.

Toxicity

Patients experiencing an overdose may present with drowsiness. Children may become agitated and restless before drowsiness. Patients should be treated with supportive measures. Dialysis will not assist in removing the drug from the body.

The maximal nonlethal dose in mice and rats is 240mg/kg.

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.

Precaution

Epileptic patients and patients at risk of convulsions. Renal impairment. Pregnancy and lactation.

Volume of Distribution

The volume of distribution of levocetirizine is 0.33±0.02L/kg.

The volume of distribution of phenylephrine is 340L.

Elimination Route

Following a 5mg oral dose of levocetirizine, a C_max of 0.27±0.04µg/mL with a T_max of 0.75±0.50h. The AUC of levocetirizine is 2.31±0.50µg*h/mL. Taking levocetirizine with food does not affect the AUC but delays T_max by 1.25 hours and lowers C_max by 36%.

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

Half Life

The average half life of levocetirizine is 7.05±1.54 hours.

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

Clearance

The average clearance of levocetirizine is 0.57±0.18mL/min/kg.

Phenylephrine has an average clearance of 2100mL/min.

Elimination Route

168 hours post dose an average of 85.4% of a radiolabeled dose was recovered with an average of 80.8% in the urine and 9.5% in the feces. In the urine, 77% of the dose was recovered as unchanged drug, 0.5% as the M8 and M9 metabolites, 0.4% as the M10a metabolite, 0.4% as the M10b metabolite, 0.3% as the M3 metabolite, 0.3% as the M4 and M5 metabolite, 0.2% as the M2 metabolite, and 0.1% as the M1 metabolite. In the feces, 9.0% of the dose was recovered as unchanged drug, 1.0% as the M4 and M5 metabolite, and 0.1% as the M1 metabolite.

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

Pregnancy: The safety of Levocetirizine in pregnancy has not been established. Therefore, it should be used with caution during pregnancy and only if the potential benefits to the mother outweigh any risks to the foetus.

Lactation: Levocetirizine passes into breast milk. So, it should be used with caution in nursing mothers and only if the expected benefit to the mother is greater than the risk to the nursing infant.

Contraindication

It is contraindicated in patients who are hypersensitive to this medication or to any of its ingredients.

Special Warning

Paediatric use: Not recommended for use in children less than 6 years of age.

Acute Overdose

Symptoms: Drowsiness, agitation, restlessness, confusion, diarrhoea, dizziness, fatigue, headache, malaise, mydriasis, pruritus, sedation, somnolence, stupor, tachycardia, tremor and urinary retention.

Management: Symptomatic and supportive treatment. Gastric lavage must be considered shortly following ingestion.

Storage Condition

Store between 20-25°C.

Innovators Monograph

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