Olopatadine (Patadin Eye Drops, Olonex Nasal Spray, Olonex Tablet): An Anti-Allergic Agent

Olopatadine is an antihistamine that also acts as a mast cell stabilizer. It comes in various formulations (eye drops, nasal spray, tablets) to treat different allergic conditions. The eye drops are classified as Ophthalmic Non-Steroid drugs, while the nasal spray and tablet are antihistamines.

How Olopatadine Works (Pharmacology)

Olopatadine is an anti-allergic molecule with multiple mechanisms of action:

• Histamine H1-receptor Antagonist: It acts with high selectivity to block histamine H1 receptors. Upon binding, it inhibits the H1 receptor signaling pathway, thereby blocking the release of inflammatory mediators like tryptase, prostaglandin D2, TNF-alpha, and pro-inflammatory cytokines. This reduces allergy symptoms.
• Mast Cell Stabilizer: It stabilizes mast cells (and rodent basophils) and inhibits the immunologically-stimulated release of histamine.

Pharmacokinetics:

• Absorption: Rapidly absorbed after intranasal administration, with peak plasma concentrations typically observed between 30 minutes and 1 hour.
• Distribution: Moderately protein-bound (approximately 55%), independent of drug concentration.
• Metabolism: Not extensively metabolized; at least six minor metabolites circulate in human plasma.
• Elimination: Primarily eliminated through urinary excretion, with a plasma elimination half-life of 8 to 12 hours.

Key Indications & Benefits

Patadin Eye Drops are indicated for the treatment of signs and symptoms (itchy, watery, red, and swollen eyes and/or eyelids) of:

• Allergic conjunctivitis
• Vernal keratoconjunctivitis
• Vernal keratitis
• Blepharitis
• Blepharoconjunctivitis
• Giant papillary conjunctivitis

Olonex Nasal Spray is indicated for the relief of symptoms of:

• Seasonal allergic rhinitis in adults and children 6 years of age and older.

Olonex Tablet is indicated for the treatment of:

• Allergic rhinitis (swelling of nasal membranes due to allergens like pollen and mold spores).
• Allergic skin conditions.
• It helps relieve allergy symptoms such as skin rashes, swelling, hives (itchy, painful eruptions that sting), itching, sneezing, and runny or stuffy nose.

Dosage & Administration

Always consult a registered physician for medication use.

Eye Drops:

• 0.1%: One drop in each affected eye two times per day at an interval of 6 to 8 hours.
• 0.2%: One drop in the affected eye once a day.
• 0.7%: One drop in each affected eye once a day.

Nasal Spray (Intranasal route only):

• Adults and Adolescents 12 years of age and older: Two sprays per nostril twice daily.
• Children 6 to 11 years of age: One spray per nostril twice daily.

Tablet:

• Adults: 1 tablet (5 mg) at a time, twice daily, in the morning and before going to bed. Dosage may be adjusted based on disease, age, or symptoms.
• Children 7 years old or over: 1 tablet (5 mg) at a time, twice daily, in the morning and before going to bed.

Missed Dose (Tablet): If you miss a dose, take it as soon as you remember. If it's almost time for the next dose, skip the missed dose and follow your regular schedule. Do not take two doses at once. Do not stop taking without doctor's instruction.

Nasal Spray Administration:

1. Shake bottle gently, remove dust cover.
2. Hold spray with forefinger and middle finger on nozzle sides, thumb underneath. Press down until fine spray appears (prime if first use or unused for >1 week by pressing several times).
3. Gently blow nose to clear nostrils.
4. Close one nostril, insert applicator into open nostril. Tilt head slightly forward, keep spray upright. Breathe in through nose, and while breathing in, firmly press white collar down once to release spray.
5. Breathe out through mouth.
6. Repeat for consecutive doses in same/other nostril.

Nasal Spray Cleaning (at least once a week):

1. Remove dust cover.
2. Gently pull off nasal applicator.
3. Wash applicator and dust cover in warm water.
4. Shake off excess water, let dry naturally (avoid additional heat).
5. Gently push applicator back onto bottle top, re-fix dust cover.

Important Considerations & Warnings

It is crucial to discuss your full medical history with your doctor before using Olopatadine.

Contraindications:

• Known hypersensitivity to any component of the product.
• Olonex 5 mg tablet is not recommended if allergic to it. Inform your doctor about current medications and pre-existing medical conditions.

Side Effects:

• Rarely: Headaches.
• Other adverse effects (may vary by formulation): Asthenia (weakness), blurred vision, burning or stinging (eyes), cold syndrome, dry eye, foreign body sensation, hyperemia (redness), hypersensitivity, keratitis (cornea inflammation), lid edema (eyelid swelling), nausea, pharyngitis (sore throat), pruritus (itching), rhinitis (nasal inflammation), sinusitis, and taste perversion.

Pregnancy & Lactation:

• Pregnancy: Olopatadine was not teratogenic in animal studies. However, there are no adequate and well-controlled studies in pregnant women. Use in pregnant women only if the potential benefit justifies the potential risk to the fetus.
• Lactation: It is not known whether topical ocular administration results in detectable quantities in human breast milk. Caution should be exercised when Olopatadine is administered to a nursing mother.

Precautions & Warnings:

• Contact Lenses (Eye Drops): Advise patients not to wear contact lenses if their eye is red. Not for contact lens-related irritation. Benzalkonium Chloride (preservative) may be absorbed by soft contact lenses. Patients wearing soft contact lenses (and whose eyes are not red) should wait at least 10 minutes after instillation before re-inserting lenses.
• Allergic Reaction: Discontinue treatment in the presence of an allergic reaction.
• Nasal Spray Priming: Before initial use, prime the nasal spray by releasing 5 sprays or until a fine mist appears. If unused for more than 7 days, re-prime by releasing 2 sprays.
• Avoid Eye Contact (Nasal Spray): Patients should be informed to avoid spraying Olonex Nasal Spray into their eyes.
• Tablet Use: Use as prescribed. Take at the same time daily. Do not exceed recommended dose. Do not stop without consulting doctor.

Drug Interactions:

• Formal drug-drug interaction studies were not conducted for Olonex Nasal Spray.
• Drug interactions with inhibitors of liver enzymes are not anticipated as olopatadine is predominantly eliminated by renal excretion.
• Drug interactions involving P450 inhibition and plasma protein binding are not expected.

Use in Special Populations:

• Geriatric Use: No overall differences in safety or effectiveness have been observed between elderly and younger adults.

Overdose Effects

• There is no specific information on Olonex overdose.
• Excessive use of any medication can have serious consequences. If overdose is suspected, seek medical attention without delay.

Storage Conditions

Store at room temperature and protect from light. It is desirable that the contents should not be used more than one month after first opening of the bottle (for eye drops, likely). Keep out of reach of children.