RYALTRIS

Indications

• Acute seasonal allergic conjunctivitis
• Perennial allergic conjunctivitis

Dosage

Children: Children aged 4 to 17 years: Apply 4 times a day. Consult product literature for specific dosing recommendations.

Adults: Apply twice daily for a maximum of 4 months, as per product literature.

Mechanism of action

Olopatadine acts as a selective antagonist at the histamine H1 receptors, preventing histamine from binding and activating the receptor. This inhibition blocks downstream signaling pathways that lead to inflammation, including the release of cytokines and other mediators from mast cells. Additionally, olopatadine stabilizes mast cells, preventing the immunologically-stimulated release of histamine and other pro-inflammatory substances, thereby mitigating the effects of allergic responses.

Pharmacodynamics

The drug effectively reduces inflammatory reactions mediated by histamine and other pro-inflammatory factors. By blocking histamine receptor activation and stabilizing mast cells, olopatadine mitigates symptoms associated with allergic conjunctivitis, such as ocular itching and tearing. It has demonstrated rapid onset of action, with effects observable within 5 minutes that can last up to 24 hours. As a non-sedating antihistamine, it provides relief without causing significant drowsiness.

Pharmacokinetics

Olopatadine is administered topically as eye drops, leading to localized effects with minimal systemic absorption. It exhibits a relatively rapid onset of action and a prolonged duration, allowing for twice-daily dosing. The pharmacokinetic profile indicates effective concentrations are achieved quickly, contributing to its rapid symptom relief. The drug's metabolism and elimination details are not specified, but its localized application suggests limited systemic exposure.

Adverse effects

• Eye discomfort
• Dry eye
• Headache
• Nausea
• Dizziness
• Corneal deposits
• Allergic dermatitis
• Vision disorders
• Malaise
• Palpitations
• Hypertension
• Myiasis
• Hyperhidrosis
• Facial swelling

Precautions

• Avoid sunlight exposure
• Discontinue use if evidence of corneal epithelial breakdown is present
• May mask symptoms of infection

Pregnancy

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

Breast-feeding

Caution is advised when using olopatadine during breastfeeding, as it is not known if it is excreted in human milk.

Storage

Store at room temperature, away from light and moisture. Once opened, use within the time specified in the product literature.

Formulations

• {'formulation': 'Olopatadine hydrochloride', 'concentration': '1 mg/ml', 'form': 'Eye drops', 'volume': '5 ml'}
• {'formulation': 'Olopatadine hydrochloride', 'concentration': '1 mg/ml', 'form': 'Eye drops', 'volume': '10 ml'}

Indications

• Management of asthma in adults and adolescents not adequately controlled with inhaled corticosteroids and short-acting beta-2 agonists
• Allergic rhinitis
• Nasal polyps

Dosage

Children: For children aged 12-17 years, initially 400 micrograms daily in 1-2 divided doses, single dose to be inhaled in the evening, reduced to 200 micrograms once daily if control is maintained.

Adults: 1 inhalation once daily; dosage may be increased to 400 micrograms twice daily if necessary.

Mechanism of action

Mometasone furoate works by binding to glucocorticoid receptors, leading to the modulation of gene expression. This results in the inhibition of pro-inflammatory cytokines and chemokines, thereby reducing inflammation in the airways and nasal passages. It also inhibits the activation of inflammatory cells such as eosinophils and mast cells, contributing to its therapeutic effects.

Pharmacodynamics

As a corticosteroid, mometasone furoate exhibits significant anti-inflammatory effects, which are crucial in the management of asthma and allergic conditions. The drug reduces airway hyper-responsiveness and decreases mucus production, leading to improved airflow and decreased symptoms such as wheezing and shortness of breath. Its rapid onset of action is beneficial for acute symptom relief.

Pharmacokinetics

Mometasone furoate is well-absorbed when administered by inhalation or nasal spray. It undergoes extensive first-pass metabolism in the liver, resulting in low systemic bioavailability. The drug is primarily excreted via the feces, with a small percentage eliminated through the urine. The half-life of mometasone furoate is approximately 5.8 hours, allowing for once-daily dosing in many cases.

Adverse effects

• Candida infection
• Nasal ulceration
• Throat irritation
• Headache
• Cough

Interactions

• Corticosteroids
• Beta2 agonists

Precautions

• Use with caution in patients with active or quiescent tuberculosis infections
• Monitor for signs of infection
• Use in hepatic impairment requires caution

Pregnancy

Use only if potential benefit outweighs risk-limited information available.

Breast-feeding

Avoid-present in milk in animal studies.

Storage

Store below 30°C. Protect from light and moisture.

Formulations

• {'form': 'Inhalation powder', 'strength': '200 micrograms per dose', 'brand': 'Asmanex Twisthaler'}
• {'form': 'Aqueous nasal spray', 'strength': '50 micrograms per dose', 'brand': 'Flixonase'}

Indications

• Asthma
• Allergic rhinitis
• Skin conditions (e.g., eczema, dermatitis)

Dosage

Children: Refer to the BNF for Children for appropriate paediatric dosing guidelines.

Adults: Refer to the specific BNF guidelines for adult dosing, which may vary based on the condition being treated.

Mechanism of action

Mometasone exerts its anti-inflammatory effects by crossing cell membranes and binding with high affinity to specific cytoplasmic glucocorticoid receptors. This interaction diminishes the release of leukocytic acid hydrolases, prevents macrophage accumulation at inflamed sites, interferes with leukocyte adhesion to capillary walls, reduces capillary membrane permeability, and inhibits the release of histamine and kinin. Additionally, mometasone inhibits the formation of scar tissue and acts through phospholipase A2 inhibitory proteins, known as lipocortins, which control the synthesis of potent inflammatory mediators like prostaglandins and leukotrienes.

Pharmacodynamics

Mometasone demonstrates medium potency as a corticosteroid, effectively reducing inflammation without significant systemic absorption due to extensive hepatic metabolism. Its local effects are favored over systemic effects, making it suitable for chronic conditions like asthma, where immediate symptom relief is not expected. The onset of action may take 1 to 2 weeks for maximum improvement in asthma symptoms following inhalation. Discontinuation of mometasone may allow for sustained asthma stability for several days.

Pharmacokinetics

Mometasone is extensively metabolized in the liver, resulting in a low systemic bioavailability. Its pharmacokinetic profile includes rapid absorption and distribution, with a half-life that supports once-daily dosing in many cases. The lack of active metabolites contributes to its safety profile, minimizing systemic effects while providing effective local action.

Interactions

• cobicistat+mometasone: Unknown (increases exposure)
• idelalisib+mometasone: Unknown (increases exposure)
• clarithromycin+mometasone: Unknown (increases exposure)

Pregnancy

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

Breast-feeding

Caution should be exercised when administering mometasone to nursing mothers, as it is not known whether it is excreted in human milk.

Storage

Store at room temperature, away from light and moisture. Do not freeze.

Formulations

• Mometasone furoate nasal spray
• Mometasone furoate inhalation aerosol
• Mometasone furoate cream
• Mometasone furoate ointment
• Mometasone furoate lotion

Mechanism of action

Unbound corticosteroids cross cell membranes and bind with high affinity to specific cytoplasmic receptors. Inflammation is decreased by diminishing the release of leukocytic acid hydrolases, prevention of macrophage accumulation at inflamed sites, interference with leukocyte adhesion to the capillary wall, reduction of capillary membrane permeability, reduction of complement components, inhibition of histamine and kinin release, and interference with the formation of scar tissue. The antiinflammatory actions of corticosteroids are thought to involve phospholipase A₂ inhibitory proteins, lipocortins, which control the biosynthesis of potent mediators of inflammation such as prostaglandins and leukotrienes. Mometasone furoate has been shown in vitro to exhibit a binding affinity for the human glucocorticoid receptor which is approximately 12 times that of dexamethasone, 7 times that of triamcinolone acetonide, 5 times that of budesonide, and 1.5 times that of fluticasone.

Pharmacodynamics

Mometasone is a medium-potency synthetic corticosteroid with antiinflammatory, antipruritic, and vasoconstrictive properties. Studies in asthmatic patients have demonstrated that mometasone provides a favorable ratio of topical to systemic activity due to its primary local effect along with the extensive hepatic metabolism and the lack of active metabolites. Though effective for the treatment of asthma, glucocorticoids do not affect asthma symptoms immediately. Maximum improvement in symptoms following inhaled administration of mometasone furoate may not be achieved for 1 to 2 weeks or longer after starting treatment. When glucocorticoids are discontinued, asthma stability may persist for several days or longer. Mometasone has been shown in vitro to exhibit a binding affinity for the human glucocorticoid receptor which is approximately 12 times that of dexamethasone, 7 times that of triamcinolone acetonide, 5 times that of budesonide, and 1.5 times that of fluticasone. The clinical significance of these findings is unknown.

Mechanism of action

Histamine is a biogenic vasoactive amine that binds to its receptors, which are G-protein coupled receptors. Signaling through the histamine H1 receptor is thought to primarily promote the activation of inflammatory reactions, such as allergy, asthma, and autoimmune diseases. H1 receptor signaling activates the intracellular transcription factors, such as IP3, PLC, PKC, DAG, and intracellular calcium ions, which all work to activate further downstream cascades. Activated downstream cascades lead to the production of cytokines, the release of mast cell inflammatory mediators, synthesis of prostacyclins, activation of platelet factor, as well as the synthesis of nitric oxide, arachidonic acid, and thromboxane, which all contribute to inflammatory reactions. Olopatadine is an anti-allergic molecule that works via several mechanisms. As a mast cell stabilizer, it stabilizes rodent basophils and human conjunctival mast cells and inhibits the immunologically-stimulated release of histamine. Olopatadine acts as an antagonist at the histamine H1 receptors with high selectivity, which is explained by a unique receptor binding pocket that consists of the aspartate residue in the third transmembrane helix and other sites in the H1 receptor. Upon binding, olopatadine blocks the H1 receptor signaling pathway, inhibiting the release of inflammatory mediators, such as tryptase, prostaglandin D2, TNF-alpha, as well as pro-inflammatory cytokines. It also decreases chemotaxis and inhibits eosinophil activation. _In vitro_, olopatadine was shown to inhibit epithelial cell intercellular adhesion molecule-1 (ICAM-1), which promotes the recruitment of migrating pro-inflammatory mediators.

Pharmacodynamics

Inflammatory reactions in response to various stimuli are mediated by endogenous mediators and other pro-inflammatory factors. Histamine receptor activation and mast cell degranulation are primary mechanisms that cause inflammatory reactions such as ocular itching, hyperemia, chemosis, eyelid swelling, and tearing of seasonal allergic conjunctivitis. Olopatadine is an anti-allergenic molecule and mast cell stabilizer that inhibits the _in vivo_ type 1 immediate hypersensitivity reaction. By blocking the effects of histamine, olopatadine works to reduce the symptoms of allergies and inflammation at various sites of administration, including the eyes and nose. It has shown to exert antihistaminic effects in isolated tissues, animal models, and humans. Olopatadine also demonstrated dose-dependent inhibition of immunologically-stimulated release of histamine from rat basophilic leukemia cells and human conjunctival mast cells _in vitro_. Olopatadine has a relatively rapid onset of action and prolonged duration, where it was shown to mediate anti-histaminic effects at 5 minutes to 24 hours post-administration. While olopatadine is a non-sedating antihistamine agent, there have been reports of somnolence in some patients taking nasal olopatadine during clinical trials. Temporary blurred vision or other visual disturbances were observed following ophthalmic administration. Olopatadine has negligible effects on alpha-adrenergic, dopamine, muscarinic type 1 and 2, and serotonin receptors. In clinical trials, there was no evidence of any effect of olopatadine on QT prolongation was observed following intranasal administration.