Sinarest Fxp

Uses

It is used for the relief of symptoms associated with seasonal and 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.

Sinarest Fxp is also used to associated treatment for these conditions: Allergic Rhinitis (AR), Chronic Idiopathic Urticaria, Seasonal Allergic Rhinitis, AntihistamineAllergic 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 Sinarest Fxp works

The H₁ histamine receptor is responsible for mediating hypersensitivity and allergic reactions. Exposure to an allergen results in degranulation of mast cells and basophils, which then release histamine and other inflammatory mediators. Histamine binds to, and activates, H₁ receptors, which results in the further release of pro-inflammatory cytokines, such as interleukins, from basophils and mast cells. These downstream effects of histamine binding are responsible for a wide variety of allergic symptoms, such as pruritus, rhinorrhea, and watery eyes.

Fexofenadine is considered an “inverse agonist” of the H₁ receptor because it binds to and stabilizes the inactive form of the receptor, preventing its activation and subsequent downstream effects. It has a potent and selective affinity for H₁ receptors, and there is no evidence that it carries antidopaminergic, antiserotonergic, anticholinergic, sedative, or adrenergic blocking activity. Fexofenadine does not cross the blood-brain barrier and thus is unlikely to cause significant CNS effects.

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

Sinarest Fxp dosage

Adults-

• Allergic rhinitis: 120 mg once daily or 60 mg twice daily
• Urticaria: 180 mg once daily

Children-

• 2-11 years: 30 mg (1 spoonful) or 5 ml twice daily
• 6 months-2 years: 15 mg (1/2 spoonful) or 2.5 ml twice daily

In case of decreased renal function, care should be taken in dose selection and it may be useful to monitor renal function.

Side Effects

Fexofenadine is generally well tolerated. The most commonly reported adverse events are headache, drowsiness, nausea, and dizziness. The incidence of these events observed with Fexofenadine hydrochloride was similar to that observed with placebo.

Toxicity

No deaths were observed following the oral administration of up to 5000 mg/kg in both mice and rats (equivalent to approximately 100-200x the recommended human dose). Single doses of up to 800 mg and chronic exposure of up to 690 mg twice daily for 1 month in humans did not result in clinically significant adverse events. Symptoms of overdosage are consistent with fexofenadine's adverse effect profile and are likely to include dizziness, drowsiness, and dry mouth.

If overdosage occurs, employ symptomatic and supportive treatment. Hemodialysis does not effectively remove fexofenadine from the blood and is therefore of no benefit.

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

Studies in the elderly, patients with hepatic impairment and patients with cardiac disease exposed to Fexofenadine showed no statistically significant differences compared to healthy individuals. As with most new drugs there is only limited data in the elderly and renally or hepatically impaired patients. Fexofenadine hydrochloride should be administered with care in these special groups.

Interaction

Co-administration of Fexofenadine Hydrochloride with either ketoconazole or erythromycin may cause increased plasma concentration of Fexofenadine. Antacid containing Aluminium and Magnesium may reduce the absorption of Fexofenadine. Fruit juices such as grapefruit, orange and apple may reduce the bioavailability of Fexofenadine.

Volume of Distribution

The volume of distribution is approximately 5.4-5.8 L/kg.

The volume of distribution of phenylephrine is 340L.

Elimination Route

Fexofenadine is rapidly absorbed following oral administration and its absolute bioavailability is approximately 33%. The T_max following oral administration is approximately 1-3 hours. The steady-state AUC_ss(0-12h) and C_max following twice daily dosing of 60mg are 1367 ng/mL.h and 299 ng/mL, respectively.

Fexofenadine AUC is decreased by >20% when coadministered with fruit juices (e.g. apple, orange, grapefruit) due to their inhibition of OATP transporters - for this reason, prescribing information recommends administering fexofenadine only with water. Similarly, coadministration of fexofenadine with a high-fat meal appears to decrease AUC and C_max by >20%.

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 terminal elimination half-life is approximately 11-15 hours.

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

Clearance

The oral clearance of fexofenadine is approximately 50.6 L/h and the renal clearance is approximately 4.32 L/h.

Phenylephrine has an average clearance of 2100mL/min.

Elimination Route

Approximately 80% of an ingested dose is eliminated in the feces, likely largely unchanged due to fexofenadine's limited metabolism, and 11% is eliminated in the urine. The principal pathways of fexofenadine elimination are biliary and renal.

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 Category B. There are no adequate and well controlled studies in pregnant women. Fexofenadine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Lactation: It is not known if Fexofenadine is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Fexofenadine is administered to a nursing woman.

Contraindication

Fexofenadine is contraindicated in patients with known hypersensitivity to Fexofenadine or any of the ingredients of Fexofenadine Hydrochloride.

Special Warning

Studies in special risk groups (elderly, renally or hepatically impaired patients) indicate that it is not necessary to adjust the dose of Fexofenadine Hydrochloride in these patients.

Acute Overdose

In case of an overdose, standard measures to remove any unabsorbed drug should be employed. Symptomatic and supportive treatment is recommended. There has been no reported case of an acute overdose of Fexofenadine hydrochloride.

Storage Condition

Store Fexofenadine at controlled room temperature 20-25 °C. Keep all medicines away from reach of children.

Innovators Monograph

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