EFEMOLINE

Indications

• Local treatment of inflammatory eye conditions
• Short-term management of eye inflammation

Dosage

Children: For children aged 2–17 years, apply every 1 hour for 24–48 hours, then reduce to 2–4 times a day as needed.

Adults: Apply every 1 hour for 24–48 hours, then reduce to 2–4 times a day as needed.

Mechanism of action

Fluorometholone acts by inducing phospholipase A2 inhibitory proteins known as lipocortins, which control the biosynthesis of inflammatory mediators like prostaglandins and leukotrienes. These proteins inhibit the release of arachidonic acid from membrane phospholipids. The drug binds to cytosolic glucocorticoid receptors, forming a receptor-ligand complex that translocates into the nucleus to bind glucocorticoid response elements in target genes, leading to modulation of gene expression related to inflammation.

Pharmacodynamics

Fluorometholone inhibits the inflammatory response, affecting various processes such as edema, fibrin deposition, capillary dilation, leukocyte migration, capillary proliferation, fibroblast proliferation, collagen deposition, and scar formation. This broad anti-inflammatory action helps in managing symptoms associated with ocular inflammation.

Pharmacokinetics

Fluorometholone is primarily administered topically as eye drops, which allows for localized action with limited systemic absorption. The pharmacokinetics of the drug in the eye involve rapid penetration into ocular tissues, with peak concentrations occurring shortly after administration. Due to its formulation, it is designed to minimize systemic exposure and side effects.

Adverse effects

• Eye discomfort
• Stinging
• Altered taste
• Visual impairment
• Cataract
• Eye disorders

Precautions

• Risk of central serous chorioretinopathy with local and systemic administration
• Consider the potential for increased intraocular pressure with prolonged use

Pregnancy

Fluorometholone should be used in pregnancy only if the potential benefit justifies the potential risk to the fetus. Consultation with a healthcare provider is recommended.

Breast-feeding

There is no specific information on the excretion of fluorometholone in human milk. Caution should be exercised when administering to breastfeeding women.

Storage

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

Formulations

• Fluorometholone 0.1% eye drops (FML Liquifilm) - 5 ml or 10 ml bottles

Indications

• Ocular redness
• Nasal congestion
• Allergic rhinitis
• Conjunctival irritation

Dosage

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

Adults: Refer to the BNF for specific adult dosing recommendations.

Mechanism of action

Tetrahydrozoline selectively stimulates alpha-1 adrenergic receptors, which are G-protein-coupled receptors that regulate vascular tone. By activating these receptors, tetrahydrozoline induces vasoconstriction of the blood vessels in the nasal passages and conjunctival tissue, thereby reducing redness and congestion.

Pharmacodynamics

As a sympathomimetic amine, tetrahydrozoline possesses vasoconstricting and decongestant properties. It effectively constricts the smaller arterioles in the nasal and conjunctival blood vessels, alleviating symptoms of allergic rhinitis and ocular irritation. Additionally, tetrahydrozoline can cross the blood-brain barrier, where it may interact with alpha-2 adrenoceptors and imidazole receptors, potentially leading to effects such as hypotension, bradycardia, sedation, and analgesia.

Pharmacokinetics

Tetrahydrozoline is absorbed systemically and can be distributed throughout the body, including crossing the blood-brain barrier. The onset of action is typically rapid, with effects observed shortly after administration. The metabolism and excretion pathways are not extensively detailed in the available literature, hence specific pharmacokinetic parameters such as half-life and elimination pathways should be referenced from additional pharmacological sources.

Adverse effects

• Headache
• Dizziness
• Dry mouth
• Nausea
• Rebound congestion with prolonged use
• Increased intraocular pressure

Precautions

• Use with caution in patients with cardiovascular disease
• Use with caution in patients with hypertension
• Caution in patients with hyperthyroidism
• Caution in pregnant and breastfeeding women

Pregnancy

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

Breast-feeding

It is not known whether tetrahydrozoline is excreted in human milk. Caution should be exercised when administering to nursing mothers.

Storage

Store at room temperature, away from moisture and heat.

Formulations

• Ophthalmic solution
• Nasal spray

Mechanism of action

There is no generally accepted explanation for the mechanism of action of ocular corticosteroids. However, corticosteroids are thought to act by the induction of phospholipase A2 inhibitory proteins, collectively called lipocortins. It is postulated that these proteins control the biosynthesis of potent mediators of inflammation such as prostaglandins and leukotrienes by inhibiting the release of their common precursor, arachidonic acid. Arachidonic acid is released from membrane phospholipids by phospholipase A2. Their primary target is the cytosolic glucocorticoid receptor. After binding the receptor the newly formed receptor-ligand complex translocates itself into the cell nucleus, where it binds to many glucocorticoid response elements (GRE) in the promoter region of the target genes. The DNA bound receptor then interacts with basic transcription factors, causing the increase in expression of specific target genes.

Pharmacodynamics

Corticosteroids such as fluorometholone inhibit the inflammatory response to a variety of inciting agents and probably delay or slow healing. They inhibit the edema, fibrin deposition, capillary dilation, leukocyte migration, capillary proliferation, fibroblast proliferation, deposition of collagen, and scar formation associated with inflammation.

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.