SPERSALLERG SDU (SINGLE DOSE UNIT)

Indications

• Allergic rhinitis
• Urticaria
• Allergic conjunctivitis
• Other allergic symptoms

Dosage

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

Adults: Refer to the BNF for specific dosing recommendations.

Mechanism of action

Antazoline binds to the histamine H1 receptor. This blocks the action of endogenous histamine, which subsequently leads to temporary relief of the negative symptoms brought on by histamine. Antihistamines, including antazoline, act as competitive, reversible inhibitors of the action of histamine at the H1 receptor, effectively preventing histamine from exerting its effects.

Pharmacodynamics

Antazoline is a histamine H1 receptor antagonist that selectively binds to but does not activate histamine H1 receptors. By blocking these receptors, it inhibits the physiological actions of endogenous histamine, leading to a reduction in symptoms associated with allergic reactions, such as vasodilation, increased vascular permeability, and sensory nerve stimulation.

Pharmacokinetics

Antazoline is absorbed after oral administration and is distributed throughout the body tissues. It undergoes hepatic metabolism and is excreted in the urine. The duration of action may vary, and specific pharmacokinetic parameters such as half-life and clearance rates can depend on individual patient factors.

Adverse effects

• Drowsiness
• Dry mouth
• Dizziness
• Blurred vision
• Gastrointestinal disturbances

Precautions

• Use caution in patients with glaucoma
• Avoid in patients with prostatic hypertrophy
• Caution is advised in patients with cardiovascular disease

Pregnancy

Antazoline should be used in pregnancy only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Antazoline is excreted in breast milk, and caution should be exercised when administering to nursing mothers.

Storage

Store in a cool, dry place, away from direct sunlight. Keep out of reach of children.

Formulations

• Tablets
• Eye drops

Indications

• Allergic rhinitis
• Nasal congestion
• Ocular irritation

Dosage

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

Adults: Refer to BNF for specific dosing information.

Mechanism of action

Tetryzoline selectively activates alpha-1 adrenergic receptors, which are G-protein-coupled receptors that mediate vasoconstriction. This action reduces vascular permeability and alleviates the symptoms of ocular irritation and nasal congestion caused by vasodilation in the conjunctival and nasal capillaries.

Pharmacodynamics

Tetryzoline exhibits vasoconstricting and decongestant effects by constricting small arterioles in the nasal passages and conjunctival blood vessels. It is capable of crossing the blood-brain barrier, which may lead to additional effects such as hypotension, bradycardia, analgesia, hypothermia, sedation, and hypnosis due to its action on alpha-2 adrenoceptors and imidazole receptors.

Pharmacokinetics

The pharmacokinetics of tetryzoline involve absorption, distribution, metabolism, and excretion characteristics typical of sympathomimetic agents. Specific data on half-life, peak plasma concentrations, and elimination routes are not provided in the source material, hence further literature should be consulted for detailed pharmacokinetic parameters.

Adverse effects

• Local irritation
• Burning sensation in the eyes
• Dryness of the nasal mucosa
• Rebound congestion with prolonged use

Precautions

• Use with caution in patients with cardiovascular disease
• Use with caution in patients with hypertension
• Avoid prolonged use to prevent rebound congestion

Pregnancy

Safety in pregnancy has not been established; use only if clearly needed.

Breast-feeding

It is not known whether tetryzoline is excreted in human milk; caution is advised.

Storage

Store at room temperature, away from moisture and heat.

Formulations

• Ophthalmic solution
• Nasal spray

Mechanism of action

Antazoline binds to the histamine H1 receptor. This blocks the action of endogenous histamine, which subsequently leads to temporary relief of the negative symptoms brought on by histamine. Antihistamine drugs are competitive, reversible inhibitors of the action of histamine at the H1 receptor. /Antihistamines/

Pharmacodynamics

Antazoline is a histamine H1 receptor antagonist. It selectively bind to but does not activate histamine H1 receptors, thereby blocking the actions of endogenous histamine.

Mechanism of action

Adrenergic receptors are G-protein-coupled receptors (GPCR) that regulate vascular tone: stimulation of alpha-1 adrenergic receptors leads to vasoconstriction. Ocular redness and nasal congestion often result from vasodilation of nasal, conjunctival, and corneal capillary blood vessels. Activation of alpha-1 adrenergic receptors have been therefore associated with a reduction of symptoms of ocular irritation and nasal congestion. Tetryzoline is a selective agonist of alpha-1 adrenergic receptors, causing vasoconstriction and alleviating ocular and nasal symptoms.

Pharmacodynamics

Tetryzoline is a sympathomimetic amine and an alpha-adrenergic agonist with vasoconstricting and decongestant properties. It works by constricting the smaller arterioles of the nasal passages and conjunctival blood vessels to ameliorate allergic rhinitis, nasal congestion, and ocular irritation. Tetryzoline is known to cross the blood-brain barrier to work on alpha-2 adrenoceptors and imidazole receptors, causing effects like hypotension, bradycardia, analgesia, hypothermia, sedation, and hypnosis.