Oxydrops

Uses

Oxymetazoline Hydrochloride is applied topically to relieve nasal congestion associated with acute or chronic rhinitis, common cold, sinusitis, and hay fever or other allergies. It is also used as nasal decongestant in otitis media.

Oxydrops is also used to associated treatment for these conditions: Acquired Blepharoptosis, Allergic Rhinitis (AR), Nasal Congestion, Postoperative Hemorrhages, Rhinorrhoea, Sinus Congestion, Acute Rhinitis, Persistent facial erythema, Airway visualization

How Oxydrops works

Oxymetazoline binds to α₁- and α₂-adrenoceptors, which are Gq-protein-coupled receptors that promote vascular smooth muscle contraction by increasing intracellular calcium levels in response to ligand activation.

Rosacea is a condition characterized by transient and persistent facial erythema. By stimulating α_1A-adrenoceptors and causing vasoconstriction, oxymetazoline is believed to diminish the symptoms of erythema. In blepharoptosis, it is hypothesized that oxymetazoline works by stimulating α-adrenergic receptors on the Müller muscle that elevates the upper eyelid, causing muscle contraction. Oxymetazoline is used in combination with tetracaine for local anesthesia in dentistry. Such combination use adds beneficial effects: the vasoconstrictor counteracts the local anesthetic agent's vasodilatory action, thereby constricting dilated arterioles and reducing blood flow to the application area. Oxymetazoline relieves nasal congestion by vasoconstricting the respiratory microvasculature, in both resistance and capacitance blood vessels on the human nasal mucosa, leading to decreased nasal mucosal blood flow, edema, and airflow resistance.

Dosage

Oxydrops dosage

Adults and children 6 years of age and older: 2-3 drops or sprays in each nostril twice daily for 3-5 days.

Children of age 2-6 years: 2-3 drops in each nostril twice daily for 3-5 days. Sprays are generally unsuitable for young children because of the small size of their nostrils. The drug is not recommended in children under the age of 2 years.

The nasal spray can be used with the patient in the upright position. Sprays are generally unsuitable for young children because of the small size of their nostril. A treatment course should not normally exceed three to five days, and on no account should it be continued for longer than two weeks because of the risk of developing "rhinitis medicamentosa".

Side Effects

Transient burning, dryness of the nasal mucosa, sneezing, Nervousness, dizziness, headache, Hypertension, palpitation or reflex bradycardia.

Toxicity

In rats, the oral LD₅₀ is 680 ug/kg and the subcutaneous LD₅₀ is 1630 ug/kg. In mice, the oral LD₅₀ is 4700 ug/kg, the intraperitoneal LD₅₀ is 48 mg/kg, and the subcutaneous LD₅₀ is 34 mg/kg.

Case reports have documented unintended overdose in both children and adults: overdose has led to dizziness, chest pain, headaches, myocardial infarction, stroke, visual disturbances, arrhythmia, hypertension, or hypotension. Accidental ingestion of topical solutions of imidazoline derivatives, including oxymetazoline, in children has resulted in serious adverse events requiring hospitalization, such as nausea, vomiting, lethargy, tachycardia, decreased respiration, bradycardia, hypotension, hypertension, sedation, somnolence, mydriasis, stupor, hypothermia, drooling, and coma. Possible rebound nasal congestion, irritation of nasal mucosa, and adverse systemic effects (particularly in children), including serious cardiovascular adverse events, have been reported with overdosage as well as prolonged or too frequent intranasal use of oxymetazoline. Overdose should be responded with close monitoring, supportive care, and symptomatic treatment.

Precaution

• Prolonged use may result in rebound congestion.
• Since oxymetazoline has systemic adverse effects, it should be used with caution in patients with
• Hypertension, cardiovascular disease or hyperthyroidism or in those receiving MAO inhibitors.

Interaction

Monoamine oxidase inhibitors (MAOIs): Concomitant use of oxymetazoline and MAOI can result in hypertensive reaction.

Tricyclic antidepressants (TCAs): TCAs may increase the effects of oxymetazoline on blood pressure.

Volume of Distribution

There is limited information on the volume of distribution of oxymetazoline.

Elimination Route

Imidazole derivatives such as oxymetazoline are readily absorbed across mucosal membranes, especially in children. In adult subjects with erythema associated with rosacea, the mean ± standard deviation (SD) C_max was 60.5 ± 53.9 pg/mL and the AUC from time 0 to 24 hours (AUC_0-24hr) was 895 ±798 pg x hr/mL following topical administration of first-dose oxymetazoline. Following once-daily topical applications for 28 days, the mean ± SD C_max was 66.4 ± 67.1 pg/mL and the AUC_0-24hr was 1050 ± 992 pg x hr/mL. Following twice-daily applications for 28 days, the mean ± SD C_max was 68.8 ± 61.1 pg/mL and the AUC_0-24hr was 1530 ± 922 pg x hr/mL.

Following single-drop ocular administration of oxymetazoline in healthy adult subjects, the mean ± SD C_max was 30.5 ± 12.7 pg/mL and the area under the concentration-time curve (AUC_inf) was 468 ± 214 pg x hr/mL. The median T_max was 2 hours, ranging from 0.5 to 12 hours.

Following nasal administration of an 0.6 mL combination product containing tetracaine and oxymetazoline in adult subjects, the maximum concentrations of oxymetazoline were reached within approximately 10 minutes. The mean C_max was 1.78 ng/mL and the AUC_0-inf value was 4.24 ng x h/mL, with a median Tmax of 5 minutes.

Half Life

Following ocular administration in healthy adults, the mean terminal half-life was 8.3 hours, ranging from 5.6 to 13.9 hours.

The terminal half-life of oxymetazoline following nasal administration of the combination product containing tetracaine and oxymetazoline in adult subjects is approximately 5.2 hours.

Clearance

There is limited information on the clearance rate of oxymetazoline.

Elimination Route

While the excretion of oxymetazoline following nasal, topical, or ophthalmic administration of oxymetazoline has not been fully characterized in humans, it is believed that the predominant route of elimination at clinically relevant concentrations of oxymetazoline is renal excretion.

Pregnancy & Breastfeeding use

Pregnancy: Safe use of oxymetazoline during pregnancy has not been established; it should be avoided by pregnant women.

Nursing Mother: It is not known whether oxymetazoline is secreted in human breast milk; caution is advised.

Contraindication

Contraindicated in patients hypersensitive to Oxymetazoine Hydrochloride.

Acute Overdose

Following a proper application, systemic action is unlikely. If, however, some of the drops are swallowed, systemic effect can be produced. Symptoms include rapid, irregular heartbeat, headache, dizziness, increased sweating, nervousness. Such symptoms are more likely to be seen in young children.

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