Olopatadin Orifarm
Antihistamine Eye Drops for Seasonal Allergic Conjunctivitis
Quick Facts About Olopatadin Orifarm
Key Takeaways About Olopatadin Orifarm
- Dual-action relief: Olopatadine works both as a histamine H1-receptor blocker and a mast cell stabiliser, providing comprehensive relief from allergic eye symptoms
- Twice-daily dosing: Apply one drop in the affected eye(s) twice daily, morning and evening, for convenient symptom management
- Contact lens precaution: Remove contact lenses before application and wait at least 15 minutes before reinserting them, as the preservative benzalkonium chloride can be absorbed by soft lenses
- Not for children under 3: Olopatadin Orifarm should not be used in children younger than 3 years of age due to insufficient safety and efficacy data
- Discard after 4 weeks: Once opened, the bottle must be discarded after 4 weeks, even if solution remains, to prevent contamination
What Is Olopatadin Orifarm and What Is It Used For?
Olopatadin Orifarm is a topical antihistamine eye drop containing olopatadine hydrochloride at a concentration of 1 mg/ml. It is specifically indicated for the treatment of signs and symptoms of seasonal allergic conjunctivitis, a condition caused by exposure to airborne allergens such as tree pollen, grass pollen, dust mites and animal dander.
Allergic conjunctivitis is one of the most common ocular conditions worldwide, affecting an estimated 10–30% of the global population according to the World Allergy Organization (WAO). When the conjunctiva – the thin transparent membrane covering the white of the eye and lining the inner eyelids – comes into contact with an allergen, the immune system triggers a cascade of inflammatory responses. Mast cells in the conjunctival tissue release histamine and other inflammatory mediators, causing the hallmark symptoms of itching, redness (hyperaemia), tearing, and swelling (chemosis) of the eyes.
Olopatadine belongs to a class of medications known as selective histamine H1-receptor antagonists with additional mast cell-stabilising properties. This dual mechanism of action distinguishes it from many other ophthalmic antihistamines. Firstly, olopatadine competes with histamine for binding at H1 receptors on conjunctival epithelial cells and nerve endings, directly blocking the itch and vasodilatory signals. Secondly, it inhibits the degranulation of mast cells, preventing the release of histamine and other pro-inflammatory mediators such as tryptase and prostaglandin D2 before they can act on surrounding tissues.
The clinical result of this combined approach is a rapid onset of symptom relief, typically within minutes of instillation, with a duration of action lasting approximately 8 hours. This pharmacological profile supports the recommended twice-daily dosing regimen. Multiple randomised controlled trials have demonstrated that olopatadine 0.1% (1 mg/ml) eye drops significantly reduce ocular itching, conjunctival redness, and tearing compared with placebo, and are at least as effective as other topical antihistamines such as ketotifen and azelastine in the treatment of seasonal allergic conjunctivitis.
Olopatadine was first approved by the United States Food and Drug Administration (FDA) in 1996 and has since become one of the most widely prescribed ophthalmic antihistamines globally. Olopatadin Orifarm is a generic formulation manufactured by Orifarm Generics, containing the same active ingredient at the same concentration as the originator product. The active substance olopatadine is also marketed under the brand names Opatanol, Toredin and Optamont in various countries.
What Should You Know Before Using Olopatadin Orifarm?
Before using Olopatadin Orifarm, inform your doctor if you have dry eyes, corneal problems, wear contact lenses, or are pregnant or breastfeeding. Do not use this medication if you are allergic to olopatadine or any of the excipients, or if you are currently breastfeeding.
Contraindications
You should not use Olopatadin Orifarm if any of the following apply to you:
- Allergy to olopatadine or any of the other ingredients in this medicine, including benzalkonium chloride, sodium chloride, disodium phosphate dodecahydrate, hydrochloric acid, sodium hydroxide, or water for injections
- Currently breastfeeding – olopatadine may pass into breast milk, and the safety for nursing infants has not been established
If you are unsure whether any of these contraindications apply to you, speak to your doctor or pharmacist before using Olopatadin Orifarm. Allergic reactions to the active substance or its excipients, while uncommon, can manifest as increased eye irritation, swelling, or skin redness around the eyes upon application. If you experience any signs of an allergic reaction, discontinue use immediately and seek medical advice.
Warnings and Precautions
Talk to your doctor, pharmacist or nurse before using Olopatadin Orifarm if any of the following situations apply to you:
- Contact lens wearers: You must remove your contact lenses before instilling the eye drops. The preservative benzalkonium chloride can be absorbed by soft contact lenses and may cause discolouration of the lenses. Wait at least 15 minutes after applying the drops before reinserting your contact lenses.
- Dry eye syndrome: Benzalkonium chloride may be irritating to the eyes, particularly in patients with dry eyes or disorders of the cornea (the clear front surface of the eye). If you experience a sensation of stinging, burning or pain in the eye after using the medicine, contact your doctor.
- Severely damaged cornea: In very rare cases, phosphate-containing eye drops such as Olopatadin Orifarm can cause cloudy patches on the cornea due to calcium deposition during treatment. This risk is primarily associated with patients who have pre-existing corneal damage.
- Use of other eye medications: If you are using other eye drops or eye ointments concurrently, allow at least 5 minutes between each medication. Eye ointments should always be applied last to avoid interference with the absorption of other topical preparations.
Use in Children
Olopatadin Orifarm can be used in children aged 3 years and older for the treatment of seasonal allergic conjunctivitis, at the same dose as in adults (one drop twice daily). It should not be used in children under 3 years of age as there are insufficient clinical data to establish the safety and efficacy of olopatadine in this age group. If your child develops eye allergy symptoms and is under 3 years old, consult your paediatrician for alternative treatment options.
Pregnancy and Breastfeeding
If you are pregnant, think you may be pregnant, or are planning to become pregnant, consult your doctor or pharmacist before using Olopatadin Orifarm. Animal reproductive studies have not demonstrated teratogenic effects with olopatadine; however, there are limited human data. The systemic absorption of topically applied olopatadine is generally low, but your doctor will weigh the benefits of treatment against any potential risks to the developing foetus before recommending this medicine during pregnancy.
Do not use Olopatadin Orifarm if you are breastfeeding. Olopatadine has been detected in the breast milk of lactating rats, and while human data are lacking, the potential for adverse effects in nursing infants cannot be excluded. If treatment with olopatadine is considered essential, your doctor may advise you to discontinue breastfeeding or choose an alternative treatment with an established safety profile during lactation. Always discuss your options with your healthcare provider.
Driving and Operating Machinery
You may experience temporary blurred vision after instilling Olopatadin Orifarm eye drops. This is a common and usually brief side effect that can affect your ability to see clearly. Do not drive or operate machinery until your vision has cleared. If blurred vision persists or recurs frequently, consult your doctor. Be aware that any medication can affect your alertness or visual acuity; read the full patient information leaflet for guidance and discuss any concerns with your doctor or pharmacist.
Important Information About Excipients
Olopatadin Orifarm contains the following excipients that require special attention:
- Benzalkonium chloride (0.1 mg/ml): This preservative is known to be absorbed by soft contact lenses and can cause discolouration. Remove contact lenses before use and wait at least 15 minutes before reinsertion. Benzalkonium chloride may also cause eye irritation, especially in patients with dry eyes or corneal disorders. Contact your doctor if you experience persistent irritation, stinging or pain after using the drops.
- Phosphate buffer (3.3 mg phosphate per ml, approximately 0.11 mg per drop): In very rare cases, patients with severely damaged corneas have developed cloudy patches (corneal calcification) due to calcium accumulation during treatment with phosphate-containing eye drops. Report any changes in your vision to your doctor promptly.
How Does Olopatadin Orifarm Interact with Other Drugs?
Olopatadine eye drops have a low potential for systemic drug interactions due to minimal absorption into the bloodstream. However, if you are using other topical eye medications, you should space them at least 5 minutes apart and apply eye ointments last to ensure optimal absorption of each preparation.
When applied topically to the eye, olopatadine achieves therapeutic concentrations locally in the conjunctival tissue while resulting in very low systemic blood levels. This minimal systemic absorption significantly reduces the risk of interactions with oral medications. No formal drug–drug interaction studies with systemic medications have been required by regulatory authorities for olopatadine eye drops, and no clinically significant systemic interactions have been reported in post-marketing surveillance or clinical trials.
Nevertheless, there are important practical considerations when using Olopatadin Orifarm alongside other ophthalmic preparations. If you are using multiple eye drop or eye ointment medications, the physical interaction between formulations can affect how well each medicine is absorbed:
| Concurrent Medication | Type | Recommendation |
|---|---|---|
| Other eye drops (e.g. lubricants, antibiotics, anti-glaucoma drops) | Ophthalmic solution or suspension | Wait at least 5 minutes between applying each eye drop to prevent dilution and wash-out |
| Eye ointments (e.g. antibiotic ointments, lubricating ointments) | Ophthalmic ointment | Always apply eye ointments last, as they form a barrier that can prevent absorption of subsequently applied drops |
| Oral antihistamines (e.g. cetirizine, loratadine, fexofenadine) | Systemic antihistamine | Can generally be used together safely; topical olopatadine has minimal systemic absorption. Inform your doctor of all medications |
| Corticosteroid eye drops (e.g. dexamethasone, prednisolone) | Ophthalmic anti-inflammatory | May be prescribed together for severe allergic eye disease; wait 5 minutes between drops |
Always tell your doctor or pharmacist about all medications you are currently taking, including prescription medicines, over-the-counter products, herbal supplements, and other eye preparations. While olopatadine has a favourable interaction profile, a complete medication history helps your healthcare provider ensure the safest and most effective treatment plan for your condition.
What Is the Correct Dosage of Olopatadin Orifarm?
The recommended dose is one drop of Olopatadin Orifarm in the affected eye or eyes, twice daily (morning and evening). Use only as directed by your doctor, and only in both eyes if specifically instructed to do so.
Always use this medicine exactly as your doctor or pharmacist has instructed. If you are uncertain about any aspect of your treatment, ask your doctor or pharmacist for clarification before proceeding.
Adults and Children (3 Years and Older)
Seasonal Allergic Conjunctivitis
Standard dose: 1 drop in the affected eye(s) twice daily
Timing: Morning and evening, approximately 8 hours apart
Duration: As directed by your doctor, typically for the duration of the allergy season
Unless your doctor specifically instructs you to apply the drops to both eyes, use Olopatadin Orifarm only in the eye or eyes that are affected by allergic symptoms. Do not exceed the prescribed dose or frequency of application.
How to Apply the Eye Drops
Proper technique is essential for effective treatment and to avoid contamination of the bottle. Follow these steps carefully each time you use Olopatadin Orifarm:
- Wash your hands thoroughly with soap and water before handling the bottle
- Unscrew the cap from the bottle. If the tamper-evident seal is loose, remove it before using the product for the first time
- Hold the bottle upside down between your thumb and middle finger, with the dropper tip pointing downward
- Tilt your head back and gently pull down your lower eyelid with a clean finger to create a small pocket between the eyelid and the eye
- Position the dropper tip close to but not touching the eye. Use a mirror if it helps with aim
- Press gently on the base of the bottle to release one drop into the pocket formed by the lower eyelid. The bottle is designed so that only a light press is needed
- Do not allow the dropper tip to touch the eye, eyelid, surrounding skin or any other surface, as this can contaminate the remaining solution in the bottle
- If both eyes require treatment, repeat the above steps for the other eye
- Replace the cap securely on the bottle immediately after use
- If the drop misses the eye, try again with a fresh drop
Missed Dose
If you forget to apply a dose, use the drops as soon as you remember. However, if it is nearly time for your next scheduled dose, skip the missed dose and continue with your regular dosing schedule. Do not apply a double dose to make up for a missed one. Consistent timing of doses helps maintain optimal therapeutic levels in the conjunctival tissue.
Overdose
If you accidentally apply too many drops, flush your eye thoroughly with lukewarm water. Do not apply any further drops until it is time for your next scheduled dose. If you or someone else (particularly a child) accidentally swallows the solution, contact your local poison control centre or emergency services immediately for assessment and advice. While the small volume in an eye drop bottle (5 ml) contains a limited amount of active substance, accidental ingestion should always be evaluated by a medical professional, especially in young children.
Stopping Treatment
Do not stop using Olopatadin Orifarm without first consulting your doctor, even if your symptoms improve. Allergic conjunctivitis often recurs with continued allergen exposure, and premature discontinuation may lead to symptom recurrence. Your doctor will advise you on the appropriate duration of treatment based on the allergy season and your individual response to the medication.
What Are the Side Effects of Olopatadin Orifarm?
Common side effects of Olopatadin Orifarm include eye pain, eye irritation, dry eyes, abnormal sensation in the eye, and headache. Most side effects are mild and temporary. Seek medical attention if you experience significant eye swelling, vision changes, or signs of an allergic reaction.
Like all medicines, Olopatadin Orifarm can cause side effects, although not everyone experiences them. The side effects listed below have been reported during clinical trials and post-marketing surveillance. Most are localised to the eye and tend to be mild and transient, resolving without the need for treatment discontinuation.
- Severe eye swelling or swelling around the eyes
- Difficulty breathing or shortness of breath
- Swelling of the face, lips, tongue or throat
- Sudden or significant loss of vision
- Severe skin reactions or widespread rash
Common
May affect up to 1 in 10 people
- Eye: Eye pain, eye irritation, dry eyes, abnormal sensation in the eye, eye discomfort
- General: Headache, tiredness (fatigue), dry nose, altered taste (dysgeusia)
Uncommon
May affect up to 1 in 100 people
- Eye: Blurred vision, decreased visual acuity, abnormal vision, corneal disorders, inflammation of the eye surface (keratitis) with or without surface damage, conjunctival inflammation or infection, eye discharge, photophobia (light sensitivity), increased tearing, itchy eyes, red eyes, eyelid disorders, eyelid itching/redness/swelling, crusting on the eyelids, foreign body sensation in the eyes
- General: Abnormal or reduced skin sensation, dizziness, runny nose, dry skin, skin inflammation (dermatitis), burning sensation on the skin
Not Known
Frequency cannot be estimated from available data
- Eye: Eye swelling (periorbital or conjunctival oedema), corneal swelling, changes in pupil size
- General: Shortness of breath (dyspnoea), increased allergic symptoms, facial swelling, drowsiness, generalised weakness, nausea, vomiting, sinus infection, skin redness and itching
Patients with a severely damaged cornea should be aware that, in very rare cases, the phosphate content of this medicine can cause cloudy patches on the cornea due to calcium accumulation during treatment. If you notice any change in your vision or new visual symptoms, report them to your doctor without delay.
It is important to report suspected adverse reactions after the medicine has been authorised. This enables continuous monitoring of the benefit–risk balance of the medicine. Healthcare professionals and patients are encouraged to report any suspected side effects to their national pharmacovigilance authority. In the United Kingdom, reports can be made via the Yellow Card Scheme. In the United States, adverse events should be reported to the FDA MedWatch programme. Other countries have their own national reporting systems.
How Should You Store Olopatadin Orifarm?
Store Olopatadin Orifarm at room temperature with no special storage requirements while the bottle is sealed. Once opened, the bottle must be discarded after 4 weeks, even if solution remains, to prevent microbial contamination.
Proper storage of ophthalmic preparations is essential to maintain their sterility, stability and therapeutic efficacy. Contaminated eye drops can cause serious eye infections that may require intensive treatment. Follow these storage guidelines carefully:
- Keep out of the sight and reach of children to prevent accidental ingestion or misuse
- Check the expiry date printed on the bottle and carton (marked "EXP"). Do not use the medicine after the last day of the stated month
- No special storage temperature is required for the unopened product. Store at room temperature
- Discard the bottle 4 weeks after first opening, regardless of whether solution remains. This is because the preservative system has limited effectiveness once the bottle has been opened repeatedly, and microbial contamination becomes an increasing risk over time
- Record the opening date on each bottle label and carton to help you track when the 4-week period expires
- Disposal: Do not dispose of unused medicine via the household waste or wastewater system. Return any unused or expired eye drops to your pharmacy for safe disposal. This helps protect the environment
Writing the date of first opening on the bottle label is one of the most important steps in safe eye drop use. Many patients forget when they opened a bottle and continue to use it beyond the recommended 4-week window. Consider setting a reminder on your phone or calendar for 4 weeks after opening to ensure timely replacement of the bottle.
What Does Olopatadin Orifarm Contain?
The active substance is olopatadine. Each millilitre of solution contains olopatadine hydrochloride equivalent to 1 mg of olopatadine. The solution also contains several excipients including the preservative benzalkonium chloride.
Understanding the composition of your eye drops is important, particularly if you have known sensitivities to certain excipients. The complete list of ingredients in Olopatadin Orifarm is as follows:
| Ingredient | Role | Notes |
|---|---|---|
| Olopatadine hydrochloride | Active substance | Equivalent to 1 mg olopatadine per ml |
| Benzalkonium chloride | Preservative | 0.1 mg/ml; can be absorbed by soft contact lenses; may irritate dry or damaged eyes |
| Sodium chloride | Tonicity agent | Adjusts the osmolarity of the solution to match tears |
| Disodium phosphate dodecahydrate (E339) | Buffer | Maintains pH stability; contains phosphate (3.3 mg/ml) |
| Hydrochloric acid (E507) | pH adjustment | Used to achieve the target pH of the solution |
| Sodium hydroxide (E524) | pH adjustment | Used to achieve the target pH of the solution |
| Water for injections | Solvent | Purified water as the vehicle for the solution |
Olopatadin Orifarm is a clear, colourless solution supplied in a 5 ml plastic dropper bottle with a screw cap. It is available in packs containing either one or three 5 ml bottles. Not all pack sizes may be available in every market.
How Does Olopatadine Work in the Body?
Olopatadine has a unique dual mechanism of action: it blocks histamine H1 receptors on conjunctival cells and simultaneously stabilises mast cells to prevent the release of histamine and other inflammatory mediators. This two-pronged approach provides both rapid symptom relief and ongoing prophylactic protection.
When an allergen such as pollen enters the eye, it binds to immunoglobulin E (IgE) antibodies on the surface of mast cells in the conjunctival tissue. This binding triggers mast cell degranulation – the rapid release of pre-formed mediators including histamine, tryptase, prostaglandin D2, and various cytokines. Histamine then binds to H1 receptors on sensory nerve endings (causing itching), blood vessels (causing redness and warmth through vasodilation), and epithelial cells (promoting swelling through increased vascular permeability).
Olopatadine interrupts this allergic cascade at two critical points. As an H1-receptor antagonist, it competes with histamine for binding at the receptor level, directly blocking the signals that produce itching, redness and swelling. Unlike many first-generation antihistamines, olopatadine is highly selective for H1 receptors and does not exhibit significant anticholinergic or anti-serotonergic activity, which reduces the risk of unwanted side effects.
As a mast cell stabiliser, olopatadine inhibits the calcium-dependent degranulation of mast cells, preventing the initial release of histamine and other pro-inflammatory mediators. This preventive action means that consistent use of olopatadine can reduce the overall inflammatory response to allergen exposure, potentially providing better symptom control than antihistamines that only block the receptor without addressing mediator release.
When applied topically, olopatadine penetrates the conjunctival tissue to achieve therapeutic local concentrations while resulting in plasma levels far below those required for systemic activity. Studies have shown peak conjunctival concentrations within 30 minutes of instillation, with sustained levels for approximately 8 hours. The minimal systemic absorption contributes to the favourable safety profile, with no clinically significant sedation or other systemic antihistaminergic effects reported at recommended ophthalmic doses.
Frequently Asked Questions About Olopatadin Orifarm
Olopatadin Orifarm is an antihistamine eye drop used to treat the signs and symptoms of seasonal allergic conjunctivitis (eye allergy). It relieves itching, redness and swelling of the eyes caused by allergens such as pollen, dust mites and animal dander. It works by blocking histamine receptors and stabilising mast cells in the eye, providing a dual mechanism of relief.
You should remove contact lenses before applying Olopatadin Orifarm eye drops and wait at least 15 minutes before reinserting them. The preservative benzalkonium chloride in the eye drops can be absorbed by soft contact lenses and may cause discolouration. If you have dry eyes or corneal problems, benzalkonium chloride may also cause irritation. Always follow these steps to protect both your lenses and your eyes.
The recommended dose is one drop in the affected eye or eyes twice daily, in the morning and evening, approximately 8 hours apart. Do not use it more often than prescribed. Only apply the drops to both eyes if your doctor has specifically instructed you to do so. Consistent timing helps maintain therapeutic drug levels in the conjunctival tissue throughout the day.
Common side effects include eye pain, eye irritation, dry eyes, abnormal sensation in the eye, and eye discomfort. General side effects include headache, tiredness, dry nose and altered taste. These effects are usually mild and temporary. If any side effect becomes severe or persists, consult your doctor. Seek immediate medical attention if you experience significant eye swelling, vision changes, or difficulty breathing.
Olopatadin Orifarm can be used in children aged 3 years and older for seasonal allergic conjunctivitis, at the same dose as adults (one drop twice daily). It should not be used in children under 3 years of age as there is insufficient data on safety and efficacy in this age group. Always follow your doctor's dosage instructions for children and supervise young children during application to ensure proper technique.
Olopatadin Orifarm eye drops should be discarded 4 weeks after first opening the bottle, even if there is solution remaining. This is to prevent contamination and infection. Write the date of first opening on the bottle label and carton. Store at room temperature with no special storage requirements. Do not use the drops after the expiry date printed on the packaging.
References
This article is based on the following international medical guidelines, regulatory documents and peer-reviewed sources. All medical claims reflect current best-practice guidelines and evidence-based medicine.
- European Medicines Agency (EMA). Olopatadine – Summary of Product Characteristics. EMA product information database. Accessed December 2025.
- Leonardi A, Bogacka E, Fauquert JL, et al. Ocular allergy: recognizing and diagnosing hypersensitivity disorders of the ocular surface. Allergy. 2012;67(11):1327–1337. doi:10.1111/all.12009
- Bielory L, Friedlaender MH. Allergic conjunctivitis. Immunology and Allergy Clinics of North America. 2008;28(1):43–58. doi:10.1016/j.iac.2007.12.005
- Abelson MB, Spitalny L. Combined analysis of two studies using the conjunctival allergen challenge model to evaluate olopatadine hydrochloride, a new ophthalmic antiallergic agent with dual activity. American Journal of Ophthalmology. 1998;125(6):797–804.
- World Allergy Organization (WAO). White Book on Allergy. Milwaukee: WAO; 2013.
- Rosenwasser LJ, O'Brien T, Weyne J. Mast cell stabilization and anti-histamine effects of olopatadine ophthalmic solution: a review of pre-clinical and clinical research. Current Medical Research and Opinion. 2005;21(9):1377–1387.
- American Academy of Ophthalmology (AAO). Preferred Practice Pattern: Conjunctivitis. AAO Clinical Guidelines. Updated 2023.
- British National Formulary (BNF). Olopatadine. NICE BNF monograph. Accessed December 2025.
Editorial Team
This article has been written and reviewed by the iMedic Medical Editorial Team, a group of licensed specialist physicians with expertise in ophthalmology, allergy medicine, and clinical pharmacology.
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Board-certified physicians specialising in ophthalmology and clinical pharmacology with documented academic and clinical experience.
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