PATADAY ONCE DAILY RELIEF
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PATADAY ONCE DAILY RELIEF (PATADAY ONCE DAILY RELIEF).
Olopatadine is a selective histamine H1 receptor antagonist and mast cell stabilizer. It inhibits release of histamine and other mediators from mast cells, reducing allergic conjunctivitis symptoms.
| Metabolism | Olopatadine undergoes minimal hepatic metabolism; approximately 60-70% excreted unchanged in urine. Metabolites include N-demethylated and N-oxide derivatives; CYP450 enzymes not significantly involved. |
| Excretion | Primarily renal excretion: approximately 60% of dose excreted unchanged in urine; fecal elimination accounts for less than 10%. |
| Half-life | Terminal elimination half-life is approximately 9 hours; allows twice-daily dosing for sustained symptom control. |
| Protein binding | Approximately 70-80% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Volume of distribution is approximately 1.4 L/kg, indicating distribution into total body water. |
| Bioavailability | Ocular bioavailability is low due to nasolacrimal drainage and systemic absorption; systemic bioavailability from ocular dose is less than 5%. |
| Onset of Action | Ocular administration: onset within 3 minutes after instillation. |
| Duration of Action | Duration of action is approximately 8-12 hours; clinical efficacy supports twice-daily dosing. |
1 drop in each affected eye once daily. The ophthalmic solution is 0.2% (olopatadine hydrochloride).
| Dosage form | SOLUTION/DROPS |
| Renal impairment | No dosage adjustment required for mild to moderate renal impairment. For severe renal impairment (CrCl <30 mL/min), use with caution as safety has not been established. |
| Liver impairment | No dosage adjustment required for mild to moderate hepatic impairment. For severe hepatic impairment (Child-Pugh class C), use with caution as safety has not been established. |
| Pediatric use | For children 2 years of age and older: 1 drop in each affected eye once daily. Safety and efficacy in children under 2 years have not been established. |
| Geriatric use | No specific dosage adjustment required. Use the same dose as for younger adults. Overall, no differences in safety or efficacy were observed between elderly and younger patients. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PATADAY ONCE DAILY RELIEF (PATADAY ONCE DAILY RELIEF).
| Breastfeeding | Olopatadine is excreted in rat milk at concentrations ~2.4 times higher than maternal plasma. No human data on M/P ratio. Caution advised; consider risk-benefit and monitor infant for anticholinergic effects. |
| Teratogenic Risk | Pregnancy Category C. In animal studies, olopatadine (0.4 mg/kg/day SC) produced no teratogenic effects but caused reduced fetal weight and delayed ossification at maternally toxic doses. No adequate human studies exist. Risk cannot be ruled out; use only if benefit outweighs potential fetal risk. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to olopatadine or any component of the formulation."]
| Precautions | ["Not for injection; for topical ophthalmic use only.","Do not wear contact lenses if eyes are red; wait at least 10 minutes after instillation before inserting lenses.","Contains benzalkonium chloride which may be absorbed by soft contact lenses.","May cause transient stinging or burning upon instillation."] |
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| Fetal Monitoring |
| No specific monitoring required beyond standard prenatal care. Observe for signs of maternal systemic effects (e.g., drowsiness, dry mouth) if used excessively. |
| Fertility Effects | No human studies on fertility. In rats, no impairment of fertility at oral doses up to 200 mg/kg/day (3533 times MRHOD). No known effects on human reproduction. |