NAZIPHIN EYE/NASAL DROPS

Indications

• Allergic rhinitis
• Urticaria
• Allergic conjunctivitis
• Other allergic reactions

Dosage

Children: For paediatric dosing, consult the BNF for Children for specific recommendations based on age and weight, as dosing may differ significantly from adult recommendations.

Adults: For adults, refer to established dosing guidelines and product information, as specific dosing can vary based on formulation and indication.

Mechanism of action

Chlorpheniramide acts as an antagonist of the H1 histamine receptor. By blocking the action of histamine, a chemical involved in allergic responses, chlorpheniramide helps to alleviate symptoms such as itching, sneezing, and runny nose. Additionally, its anticholinergic properties contribute to its effectiveness in reducing secretions and promoting sedation.

Pharmacodynamics

The pharmacodynamic effects of chlorpheniramide include relief from allergic symptoms, sedation, and anticholinergic effects, such as dry mouth and decreased nasal secretions. The onset of action typically occurs within 1 to 2 hours after oral administration, with effects lasting for several hours. Its sedative properties can be particularly beneficial for patients who experience difficulty sleeping due to allergy symptoms.

Pharmacokinetics

Chlorpheniramide is well-absorbed after oral administration and reaches peak plasma concentrations within 1 to 2 hours. It is extensively metabolized in the liver, and its metabolites are excreted primarily in the urine. The elimination half-life ranges from 6 to 12 hours, allowing for once or twice daily dosing in most cases. Factors such as age, liver function, and concurrent medications can influence its pharmacokinetics.

Contra-indications

• Hypersensitivity to chlorpheniramine or any of its components
• Severe asthma exacerbations
• Glaucoma
• Prostatic hypertrophy
• Peptic ulcer disease

Adverse effects

• Drowsiness
• Dizziness
• Dry mouth
• Constipation
• Blurred vision
• Urinary retention
• Headache

Interactions

• Other central nervous system depressants (e.g., alcohol, benzodiazepines)
• Monoamine oxidase inhibitors (MAOIs)
• Anticholinergic drugs
• Tricyclic antidepressants

Precautions

• Caution in patients with cardiovascular disease
• Caution in patients with hypertension
• Caution in elderly patients due to increased sensitivity
• Use with caution in hepatic or renal impairment

Pregnancy

Chlorpheniramine should only be used during pregnancy if the potential benefits outweigh the risks. Consult a healthcare provider for further guidance.

Breast-feeding

Chlorpheniramine is excreted in breast milk. It is recommended to avoid use while breastfeeding unless deemed necessary by a healthcare provider.

Storage

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

Formulations

• Tablets
• Syrup
• Injection

Indications

• Nasal congestion
• Allergic rhinitis
• Ocular redness and irritation
• Sinusitis

Dosage

Children: Refer to the BNF for Children for specific dosing information.

Adults: Refer to the BNF for specific dosing information.

Mechanism of action

Naphazoline is a vasoconstrictor that functions by stimulating alpha adrenergic receptors in arterioles, leading to decreased congestion at the site of administration. It causes the release of norepinephrine in sympathetic nerves, which binds to alpha adrenergic receptors and causes vasoconstriction. Additionally, naphazoline is a mild beta adrenergic receptor agonist, potentially resulting in rebound vasodilation after the alpha adrenergic stimulation has ceased. Its norepinephrine release triggers a negative feedback loop that reduces norepinephrine production, which can contribute to rhinitis medicamentosa upon cessation after prolonged use.

Pharmacodynamics

Naphazoline is a sympathomimetic alpha adrenergic agonist that acts to vasoconstrict nasal or ocular arterioles, resulting in reduced congestion at the site of administration. This property makes it effective in managing symptoms of nasal congestion and eye irritation.

Pharmacokinetics

The pharmacokinetics of naphazoline are characterized by its local action at the site of administration, with rapid onset of action. It undergoes systemic absorption; however, detailed pharmacokinetic parameters such as half-life, distribution volume, and elimination routes are not well documented in the provided sources.

Adverse effects

• Burning or stinging sensation in the nose or eyes
• Rebound congestion
• Increased blood pressure
• Tachycardia
• Headache
• Nausea

Precautions

• Use with caution in patients with cardiovascular disease
• Caution in patients with hypertension or hyperthyroidism
• Avoid prolonged use to prevent rhinitis medicamentosa

Pregnancy

Naphazoline should only be used during pregnancy if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Caution is advised when using naphazoline while breastfeeding.

Storage

Store in a cool, dry place, away from direct sunlight.

Formulations

• Nasal spray
• Eye drops

Mechanism of action

Naphazoline is a vasoconstrictor that functions by stimulating alpha adrenergic receptors in arterioles leading to decreased congestion at the site of administration. Naphazoline causes the release of norepinephrine in sympathetic nerves. Norepinephrine binds to alpha adrenergic receptors and causes vasoconstriction. Naphazoline is also a mild beta adrenergic receptor agonist, which can cause rebound vasodilation after the alpha adrenergic stimulation has ended. Naphazoline's release of norepinephrine also triggers a negative feedback loop which decreases production of norepinephrine, which can lead to rhinitis medicamentosa after long term use when naphazoline is stopped.

Pharmacodynamics

Naphazoline is a sympathomimetic alpha adrenergic agonist that acts to vasoconstrict nasal or ocular arterioles, resulting in reduced congestion at the site of administration.