EMADINE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for EMADINE (EMADINE).
Emedastine is a selective histamine H1 receptor antagonist that inhibits histamine-induced vascular permeability, edema, and pruritus.
| Metabolism | Hepatic via CYP450 enzymes, primarily CYP3A4 and CYP2D6 |
| Excretion | Renal: approximately 60% as unchanged drug and metabolites; fecal: approximately 15% |
| Half-life | Terminal elimination half-life: 4–6 hours; clinically, dosing every 4–6 hours as needed for symptom relief |
| Protein binding | Approximately 50% bound to plasma proteins |
| Volume of Distribution | Not well defined; estimated around 1.2 L/kg, suggesting distribution into total body water |
| Bioavailability | Ophthalmic: systemic bioavailability < 10% due to local administration and low absorption |
| Onset of Action | Ophthalmic: approximately 3–5 minutes after instillation |
| Duration of Action | Ophthalmic: up to 8–12 hours; prolonged effect due to local binding in conjunctival tissue |
| Molecular Weight | 302.4 |
| Action Class | Calcium channel blockers- Dihydropyridines (DHP) |
| Brand Substitutes | Amlin 5mg Tablet, Amset 5mg Tablet, Amlip 5 Tablet, Amcard 5 Tablet, Camlodip 5mg Tablet, Lupidip 10mg Tablet, Amlokind 10mg Tablet, Amcard 10 Tablet, Amlip 10 Tablet, Primodil 10 Tablet |
1 drop of 0.05% ophthalmic solution in the affected eye(s) twice daily, approximately 8 hours apart.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | No dosage adjustment required for renal impairment. |
| Liver impairment | No dosage adjustment required for hepatic impairment. |
| Pediatric use | Safety and efficacy in pediatric patients below 3 years have not been established. For children 3 years and older, same as adult dosing. |
| Geriatric use | No specific dosage adjustment recommended, but caution advised due to possible increased sensitivity. |
| 1st trimester | No adequate studies in pregnant women; use only if potential benefit justifies risk to fetus. Animal studies have not revealed teratogenic effects at clinically relevant doses. |
| 2nd trimester | Same as T1; no known risk of fetal harm from limited human data. |
| 3rd trimester | Same as T1; consider risk-benefit due to potential for maternal systemic effects near term. |
Clinical note
Comprehensive clinical and safety monograph for EMADINE (EMADINE).
| Placental transfer | Based on molecular weight (302 Da) and lipophilicity, placental transfer is likely but not well characterized in humans. |
| Breastfeeding | It is not known if emadine (emedastine) is excreted in human milk. Caution should be exercised when administered to a nursing woman. Consider alternative antihistamines with more safety data. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to emedastine or any component of the formulation
| Precautions | Not for injection, Should not be used to treat contact lens related irritation, Patients should not wear contact lenses if eyes are red |
| Food/Dietary | No known food interactions with ophthalmic emedastine. Systemic absorption is negligible; therefore, no dietary restrictions are necessary. |
| Clinical Pearls | Emadine (emedastine difumarate) is an ocular antihistamine for allergic conjunctivitis. Onset of action is within minutes; duration ~8 hours. Not for contact lens-related irritation; remove lenses before use. May cause transient burning or stinging. Use with caution in patients with dry eye or corneal compromise due to preservative benzalkonium chloride (BAC). Systemic absorption is minimal, but caution in severe hepatic impairment. |
Loading safety data…
| Lactation Rating |
| L3 (Moderately Safe) |
| Teratogenic Risk | FDA Pregnancy Category B. No evidence of teratogenicity in animal studies; insufficient human data. Avoid use in first trimester unless benefit outweighs risk. |
| Fetal Monitoring | Monitor maternal liver function and renal function; assess fetal growth if used long-term. |
| Fertility Effects | No known adverse effects on fertility in animal studies; no human data. |
| Patient Advice | Remove contact lenses before instilling drops and wait at least 10 minutes before reinserting. · Do not touch the dropper tip to any surface to avoid contamination. · May cause temporary blurred vision; avoid driving until vision clears. · Use exactly as prescribed; do not use more frequently than directed. · Report eye pain, vision changes, or worsening redness to your doctor. |