ALCAFTADINE

Clinical safety rating: caution

Comprehensive clinical and safety monograph for ALCAFTADINE (ALCAFTADINE).

How it works

Selective histamine H1 receptor antagonist; inhibits histamine release from mast cells and reduces ocular itch associated with allergic conjunctivitis.

What the body does with it

Metabolism	Not extensively metabolized; primarily excreted unchanged in urine. Cytochrome P450 metabolism is minimal.
Excretion	Primarily renal (approximately 50% unchanged), with the remainder as metabolites; negligible biliary/fecal elimination.
Half-life	Terminal elimination half-life is approximately 2 hours (range 1.5–3 h) after topical ocular administration, appropriate for twice-daily dosing.
Protein binding	Approximately 40% bound to plasma proteins.
Volume of Distribution	Vd is approximately 1.4 L/kg, indicating distribution beyond plasma into extravascular tissues.
Bioavailability	Systemic bioavailability after topical ocular administration is low (estimated < 0.5%) due to dilution, local metabolism, and limited corneal penetration.
Onset of Action	Rapid onset of action within 15–30 minutes after topical ocular administration.
Duration of Action	Duration of action is approximately 8–12 hours with twice-daily dosing for ocular itch relief; requires regular dosing for sustained effect.

Classification & Brands

Dosing & administration

1 drop of 0.25% ophthalmic solution in each affected eye twice daily.

Dosage form	SOLUTION/DROPS
Renal impairment	No dose adjustment required for any degree of renal impairment.
Liver impairment	No dose adjustment required for any degree of hepatic impairment.
Pediatric use	Children 2 years and older: same as adult dose. Safety and efficacy in children under 2 years not established.
Geriatric use	No specific dose adjustment needed; use same dose as for younger adults.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for ALCAFTADINE (ALCAFTADINE).

Breastfeeding	It is not known whether alcaftadine is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when alcaftadine is administered to a nursing woman. The M/P ratio has not been established.
Teratogenic Risk	Alcaftadine is classified as Pregnancy Category B. Animal studies have not demonstrated teratogenic effects at doses up to 2400 times the human ocular dose. There are no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, alcaftadine should be used during pregnancy only if clearly needed.

Warnings & precautions

■ FDA Black Box Warning

None

Side Effect Profile

Common Effects	Eye irritation Itching Stinging in the eyes Burning eyes
Serious Effects

Absolute Contraindications

["Hypersensitivity to alcaftadine or any component of the formulation"]

Clinical Precautions

Precautions	["Do not inject; for topical ophthalmic use only","Avoid wearing contact lenses if eyes are red","May cause temporary blurred vision after instillation","Use with caution in patients with known hypersensitivity"]
Food/Dietary	No specific food interactions reported. As an ophthalmic preparation, systemic absorption is minimal and unlikely to be affected by food.

Clinical Tips & Counseling

Drug interactions

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ALCAFTADINE

Clinical safety rating: caution

Comprehensive clinical and safety monograph for ALCAFTADINE (ALCAFTADINE).

How it works

Selective histamine H1 receptor antagonist; inhibits histamine release from mast cells and reduces ocular itch associated with allergic conjunctivitis.

What the body does with it

Metabolism	Not extensively metabolized; primarily excreted unchanged in urine. Cytochrome P450 metabolism is minimal.
Excretion	Primarily renal (approximately 50% unchanged), with the remainder as metabolites; negligible biliary/fecal elimination.
Half-life	Terminal elimination half-life is approximately 2 hours (range 1.5–3 h) after topical ocular administration, appropriate for twice-daily dosing.
Protein binding	Approximately 40% bound to plasma proteins.
Volume of Distribution	Vd is approximately 1.4 L/kg, indicating distribution beyond plasma into extravascular tissues.
Bioavailability	Systemic bioavailability after topical ocular administration is low (estimated < 0.5%) due to dilution, local metabolism, and limited corneal penetration.
Onset of Action	Rapid onset of action within 15–30 minutes after topical ocular administration.
Duration of Action	Duration of action is approximately 8–12 hours with twice-daily dosing for ocular itch relief; requires regular dosing for sustained effect.

Classification & Brands

Dosing & administration

1 drop of 0.25% ophthalmic solution in each affected eye twice daily.

Dosage form	SOLUTION/DROPS
Renal impairment	No dose adjustment required for any degree of renal impairment.
Liver impairment	No dose adjustment required for any degree of hepatic impairment.
Pediatric use	Children 2 years and older: same as adult dose. Safety and efficacy in children under 2 years not established.
Geriatric use	No specific dose adjustment needed; use same dose as for younger adults.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for ALCAFTADINE (ALCAFTADINE).

Breastfeeding	It is not known whether alcaftadine is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when alcaftadine is administered to a nursing woman. The M/P ratio has not been established.
Teratogenic Risk	Alcaftadine is classified as Pregnancy Category B. Animal studies have not demonstrated teratogenic effects at doses up to 2400 times the human ocular dose. There are no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, alcaftadine should be used during pregnancy only if clearly needed.

Warnings & precautions

■ FDA Black Box Warning

None

Side Effect Profile

Common Effects	Eye irritation Itching Stinging in the eyes Burning eyes
Serious Effects

Absolute Contraindications

["Hypersensitivity to alcaftadine or any component of the formulation"]

Clinical Precautions

Precautions	["Do not inject; for topical ophthalmic use only","Avoid wearing contact lenses if eyes are red","May cause temporary blurred vision after instillation","Use with caution in patients with known hypersensitivity"]
Food/Dietary	No specific food interactions reported. As an ophthalmic preparation, systemic absorption is minimal and unlikely to be affected by food.

Clinical Tips & Counseling

Drug interactions

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