SYNUX NASAL ​SPRAY

Indications

• Nasal congestion due to rhinosinusitis
• Allergic rhinitis
• Non-allergic rhinitis

Dosage

Children: For children aged 2-6 years, the recommended dose is 0.05% solution, 1 spray into each nostril up to twice daily, and for children over 6 years, the usual dose is 0.1% solution, 1 spray into

Adults: The usual adult dose is 0.1% solution, 1 spray into each nostril up to twice daily for a maximum of 7 days.

Mechanism of action

Xylometazoline acts as a selective agonist at alpha-2B adrenoceptors and has affinity for alpha-1A, alpha-2A, alpha-2C, alpha-1B, and alpha-1D adrenoceptors. Its action leads to vasoconstriction of the blood vessels in the nasal mucosa, which decreases nasal resistance and increases airflow during both inspiration and expiration. The relief of nasal congestion can also alleviate associated symptoms such as earache and sore throat from mouth breathing.

Pharmacodynamics

As a sympathomimetic agent, xylometazoline causes vasoconstriction in the nasal mucosa, with a median onset of subjective relief of nasal congestion occurring in about 1.7 minutes and peak relief at around 30 minutes. However, long-term use can lead to rebound congestion and rhinitis medicamentosa, suggesting it should be used temporarily. Additionally, xylometazoline shows anti-oxidant properties, which may contribute to its beneficial effects in inflammation.

Pharmacokinetics

Xylometazoline is administered topically in the nasal cavity, allowing for rapid onset of action. The pharmacokinetics regarding absorption, metabolism, and excretion are not extensively detailed in the provided data, and further specific studies may be required to fully understand its systemic effects.

Contra-indications

• Hypersensitivity to xylometazoline or any of its components
• Severe hypertension
• Severe coronary artery disease
• Use of monoamine oxidase inhibitors (MAOIs) within 14 days

Adverse effects

• Local irritation or burning sensation in the nasal passages
• Dryness of the nasal mucosa
• Rebound nasal congestion (rhinitis medicamentosa) with prolonged use
• Headaches
• Nausea
• Palpitations
• Increased blood pressure

Interactions

• Caution with other sympathomimetic agents
• Caution with MAOIs, which may enhance hypertensive responses
• Potential interaction with tricyclic antidepressants

Precautions

• Use with caution in patients with cardiovascular disease
• Use with caution in patients with hyperthyroidism
• Not recommended for prolonged use beyond a few days
• Monitor for signs of rebound congestion

Pregnancy

Limited data on the use of xylometazoline in pregnancy. It should be used only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Xylometazoline is excreted in breast milk. Caution is advised when used during breastfeeding.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Formulations

• Nasal spray (0.1% and 0.05%)
• Nasal drops (0.1% and 0.05%)

Mechanism of action

Nasal congestion is caused by various etiologies, such as rhinosinusitis and allergic or non-allergic rhinitis, leading to congestion of the venous sinusoids lining the nasal mucosa. Activation of α-adrenergic receptors leads to vasoconstriction of the blood vessels of the nasal mucosa and resumption of nasal airflow. As the most abundantly expressed in the human nasal mucosa, α_1A- and α_2B-adrenoceptors may play the most important role in vasoconstriction of the human nasal mucosa. Xylometazoline is a more selective agonist at α_2B-adrenoceptors, with affinity at α_1A-, α_2A-, α_2C-, α_1B-, and α_1D-adrenoceptors. Xylometazoline decreases nasal resistance during inspiration and expiration and increases the volume of nasal airflow. Compared to [oxymetazoline], another imidazoline nasal decongestant, xylometazoline had a slightly faster onset of action although they had a similar duration of action. In one study, subjects with nasal congestion reported relief of earache and sore throat in addition to nasal decongestion: it is speculated that oxymetazoline mediates this effect by causing vasoconstriction of the nasal mucosa that contains the venous sinuses and nasal decongestion allows breathing through the nose, providing relief from sore throat caused by mouth breathing that dries and irritates the throat.

Pharmacodynamics

Xylometazoline is a sympathomimetic agent that causes vasoconstriction of the nasal mucosa. In one study comprising subjects with nasal congestion associated with the common cold, the median time of onset of subjective relief of nasal congestion was about 1.7 minutes and the time of subjective peak relief of nasal congestion was 30 minutes. Previous studies reported rebound swelling, rebound nasal congestion, rhinitis medicamentosa, and shorter duration of decongestant effect from the long-term use of xylometazoline in healthy volunteers, suggesting that the drug is most effective if used temporarily. An early _in vitro_ study demonstrated xylometazoline to exert anti-oxidant actions, where it inhibited microsomal lipid peroxidation and mediated hydroxyl radical scavenging activity. This suggests that xylometazoline has a beneficial effect against oxidants, which play a role in tissue damage in inflammation.