Action and mechanism- Antiallergic. Levocabastine is a cyclohexyl-piperidine derivative that acts as an antiallergic due to its antagonistic effects on H1 histaminergic receptors. It has no effects on other receptors such as serotonergic, cholinergic or dopaminergic. It has antagonistic effects on alpha adrenergic receptors at doses well above therapeutic levels. Pharmacokinetics Ophthalmic route:- Absorption: slow and incomplete, with a bioavailability of 30-60%. Cmax (1.2 ng/ml) is reached at 1.2 h. The effects appear at 15 min and last for 4 h.- Distribution: protein binding of 55%. Its Vd is 1.1 l/kg.- Metabolism: minimally by glucuronidation, giving rise to the inactive metabolite, acyl-glucuronide of levocabastine.Enzyme-inducing/inhibiting capacity: does not appear to have a significant effect.- Excretion: in urine (75-80%; 65-70% unchanged) and faeces (20%). Its t1/2 is 33-40 h and its CLt is 30 ml/min.Pharmacokinetics in special situations:- Children: after nasal and ophthalmic administration, cmax of 18.2 ng/ml has been found. The data are very limited and do not allow conclusions to be drawn about its differences with adults.- Elderly: they have a slightly slower elimination, slightly increasing tmax (15%) and cmax (26%).- Renal impairment: patients with moderate to severe impairment (CLcr 10-50 ml/min) presented an increase in t1/2 (up to 95 h) and AUC (56%). Levocabastine is haemodialysable (10% of dose).- Hepatic impairment: no data available. Indications- Symptomatic treatment of [ALLERGIC CONJUNCTIVITIS]. DosageReactine Levocabastine:- Adults and adolescents from 12 years of age: 1 drop in each eye, 2 times a day. If necessary, the dose may be increased to 1 drop in each eye, 3-4 times a day.- Children < 12 years: not recommended.- Elderly: no specific dosage recommendations have been made.Duration of treatment: Consult your doctor and/or pharmacist if symptoms continue or worsen after 2 days of use.Dosage in renal impairmentNo specific dosage recommendations have been made.Dosage in hepatic impairmentNo specific dosage recommendations have been made.Instructions for correct administrationExtreme precautions should be taken to avoid contaminating the eye drops throughout the administration of the medicine. To do this, wash your hands before administration and avoid contact of the dropper with any surface of the body, including the eyelids and surrounding areas.Shake the eye drops before administration.Rules for administering eye drops:1. Tilt your head back.2. Pull back the lower eyelid with an index finger and look up.3. 3. Instill one drop into the conjunctival sac, holding the bottle upright with the dropper pointing downwards. 4. After applying the drop, blink repeatedly to distribute the eye drops. To reduce possible systemic absorption of levocabastine, it is recommended to press the lacrimal sac for one minute or close the eyelids tightly for 2-3 minutes immediately after administering the eye drops. If other ophthalmic medications are being used, it is recommended to space administrations at least 10 minutes apart. Those presentations in gel form should be administered last. Contraindications- Hypersensitivity to levocabastine or any other component of the medication. Precautions- [KIDNEY FAILURE]. Levocabastine is excreted unchanged in urine, with a decrease in its elimination being observed in patients with kidney failure. Although no specific dosage recommendations have been made, caution is advised in the absence of specific studies in these patients. Warnings regarding excipients: - May cause eye irritation as it contains benzalkonium chloride. - May cause discoloration and alterations in soft contact lenses; therefore, it is recommended to avoid contact with them. Contact lenses should be removed before application and wait at least 15 minutes before reinserting them. Patient advice - Take extreme hygiene measures during administration. Wash your hands with soap and water before administering levocabastine, and avoid touching the bottle’s dropper to any surface.- Consult your doctor and/or pharmacist if symptoms continue or worsen while using levocabastine.InteractionsNo interactions have been reported.PregnancyFDA Category C.Animal Safety: Teratogenicity (polydactyly, brachygnathia, hydrocephalus) and increased fetal resorption have been reported in rats after systemic administration at doses of 16.5000 MRHD by ophthalmic route. These effects were not reported at lower doses.Human Safety: Adequate and well-controlled studies in humans are not available. The administration of antihistamines during pregnancy was not associated with an increased incidence of congenital malformations, although a small increase in cardiovascular defects, premature birth, and low birth weight was observed. Their administration is only accepted if there are no safer therapeutic alternatives, and the benefits outweigh the possible risks. Effects on fertility: No specific studies have been conducted in humans. Breastfeeding Safety in animals: No data available. Safety in humans: Levocabastine is excreted in milk (0.3%) after oral administration. There are no data relating to ophthalmic administration, but given its low dose and poor absorption, significant concentrations in milk are not expected. However, the consequences it could have for infants have not been evaluated, therefore it is advisable to use with caution. Children Safety and efficacy in children under 4 years of age have not been evaluated, therefore it is recommended to avoid its use. Safety and efficacy in children under 12 years of age have not been evaluated, therefore it is recommended to avoid its use. Elderly No specific problems have been described in the elderly that would require a dosage adjustment. Effects on driving Levocabastine does not appear to have significant effects on the ability to drive. However, as with any other drug administered ophthalmically, blurred vision may appear immediately after use. It is recommended to avoid driving until vision is normal. Adverse reactions Adverse reactions are described according to each frequency grouping, considering the following as very common (>10%), common (1-10%), uncommon (0.1-1%), rare (0.01-0.1%), very rare (<0.01%) or of unknown frequency (cannot be estimated from the available data).- Digestive: common [DRY MOUTH].- Neurological/psychological: very rare [HEADACHE]; frequency unknown [SEDATION], [DROWSINESS].- Respiratory: common [EPISTAXIS], [COUGH].- Dermatological: very rare [CONTACT DERMATITIS], [URTICARIA], [ANGIOEDEMA].- Allergic: very rare [HYPERSENSITIVITY REACTIONS].- Ophthalmological: very common [EYE IRRITATION]; Frequent local ocular reactions of an irritant type, including burning, stinging or [EYE ITCHING]; very rare [EYE PAIN], [CONJUNCTIVITIS], [EYELID EDEMA], [EYE EDEMA], [BLEPHARITIS], [RED EYE], [BLURRED VISION]. - General: frequency unknown [ASTHENIA]. Overdose Symptoms: There is no clinical experience. In case of ingestion of the eye drops (which would involve the administration of a total dose of 2 mg) some sedation may occur. Measures to be taken: - Antidote: There is no specific antidote. - General elimination measures: It is recommended to drink plenty of fluids to promote renal excretion. - Monitoring: No special surveillance appears necessary. - Treatment: Symptomatic. Shelf life Before opening: 24 months. After opening: 28 days