Alcaftadine: what it treats, how to use it, side effects
Last updated September 7, 2026.
**Alcaftadine ophthalmic is an antihistamine eye drop that relieves itching caused by eye allergies.** It blocks histamine, a chemical involved in allergic symptoms. Stop using it and get medical advice if you develop eye pain, vision changes, or increasing redness.
What does it treat?
You can use alcaftadine for itchy eyes caused by pollen, ragweed, grass, animal hair, or dander. These allergies can cause allergic conjunctivitis, with itching and watering after exposure. Alcaftadine is available as Lastacaft and generic eye drops; it does not treat irritation caused by contact lenses.
How do you take it?
Use the 0.25% eye drop solution: the adult dose is one drop in each affected eye once daily, with no more than one dose daily. Meals do not affect use. Wash your hands and keep the dropper tip from touching your eye or other surfaces. Remove contacts first and wait at least 10 minutes before replacing them; leave them out if your eyes are red. If you miss a dose, use it when remembered unless the next dose is almost due; skip rather than double it. Stop and call a doctor for eye pain, vision changes, increasing redness, or itching that worsens or lasts more than 72 hours.
Side effects to know
- Common: You may notice burning, stinging, irritation, itching, or redness after using the drops, and headache or a runny nose can occur.
- Serious: Stop using the drops and get medical help for facial swelling, a new allergic rash, or marked eyelid swelling. Call 911 for trouble breathing or swelling of your tongue or throat.
Who should not take it?
Do not use alcaftadine if you are allergic to an ingredient or the solution is cloudy or discolored. Ask a doctor before using it in a child younger than 2. Review your other medicines and eye treatments with a clinician or pharmacist. If you are pregnant or breastfeeding, discuss use first: pregnancy data are limited, and information about breast milk, infant effects, and milk production is unavailable. Labeling specifies no alcohol restriction.
When is it an emergency?
If you swallow the drops or use too much, call Poison Control at 1-800-222-1222 for instructions; do not wait for symptoms. The labeling does not describe a specific overdose symptom pattern. Call 911 for collapse or breathing trouble, including a severe allergic reaction with throat swelling. Sudden vision loss or severe eye pain requires immediate emergency evaluation.
What a Pymander AI doctor consult looks like
Illustrative example, not a real member's messages.
Common questions
What is the maximum daily dose?
Use one drop in each affected eye once daily. Do not add another dose because itching returns. Contact a clinician if the usual dose is not controlling your symptoms.
Can I drink alcohol while using alcaftadine?
The label does not give a specific alcohol restriction. Sleepiness has been reported after use. If you feel sleepy, avoid alcohol and driving.
Can I use it during pregnancy or breastfeeding?
Talk with your clinician first. Pregnancy use should depend on whether the expected benefit justifies potential risks. Breastfeeding decisions should weigh your need for treatment, breastfeeding benefits, and possible infant effects.
Do I need to use it with food?
You can use the drops before or after meals. Keep your usual diet unless your clinician advises otherwise. Use them around the same time each day to help you remember.
What are the signs of an overdose?
The label does not identify reliable overdose signs. If you swallow the solution or use too much, call Poison Control at 1-800-222-1222 even if you feel well. Call 911 for collapse or breathing trouble.
Can I use other eye drops with it?
Separate alcaftadine and other eye products by at least 5 minutes. Tell your pharmacist which products you use. Ask before adding another allergy eye medicine.