Matropin2%

Matropin is an anticholinergic (antimuscarinic) ophthalmic agent used for the following indications:

Established / FDA-approved uses

• Mydriasis and cycloplegia for diagnostic procedures: Matropin ophthalmic solution is used to dilate the pupil and temporarily paralyze accommodation of the ciliary muscle, allowing accurate refraction testing and thorough examination of the fundus and other internal structures of the eye.
• Treatment of anterior uveitis and iritis (adjunctive use): Matropin is used as an adjunct to reduce pain from ciliary muscle spasm, help prevent formation of posterior synechiae (adhesions between the iris and lens), and promote ocular rest during active inflammation.

Not indicated for

Matropin is not indicated for the treatment of glaucoma and should not be used when angle-closure glaucoma is present or suspected (see Contraindications).

Each mL of Homatropine Hydrobromide ophthalmic solution contains Homatropine Hydrobromide as the active pharmaceutical ingredient, typically formulated as a sterile ophthalmic solution at a strength of 2% or 5% (20 mg/mL or 50 mg/mL). Formulations may also contain preservatives (e.g., benzalkonium chloride) and other inactive ingredients (e.g., boric acid, sodium chloride, purified water) to maintain isotonicity and sterility for ocular use.

Matropin is a semisynthetic anticholinergic (antimuscarinic) compound used topically in the eye as a mydriatic (pupil-dilating) and cycloplegic (accommodation-paralyzing) agent. It is chemically related to atropine but has a shorter duration of action, which makes it useful for routine diagnostic eye examinations as well as for symptomatic management of anterior segment inflammation such as uveitis and iritis. Matropin is available as an ophthalmic solution for topical instillation into the conjunctival sac.

Matropin belongs to the anticholinergic (antimuscarinic) ophthalmic mydriatic and cycloplegic therapeutic class.

Homatropine Hydrobromide acts as a competitive antagonist of acetylcholine at muscarinic receptors located in the sphincter muscle of the iris and the ciliary muscle of the eye. By blocking these receptors, Homatropine Hydrobromide produces:

• Mydriasis — relaxation of the iris sphincter muscle, resulting in pupil dilation.
• Cycloplegia — paralysis of the ciliary muscle, resulting in loss of accommodation (near-focusing ability), which allows accurate cycloplegic refraction.

Onset of mydriasis typically occurs within 10–30 minutes of instillation, with maximal effect around 30–90 minutes. Compared with atropine, Homatropine Hydrobromide has a shorter duration of action, with mydriasis and cycloplegia generally resolving within 1–3 days rather than 1–2 weeks, which is one reason it is preferred for routine diagnostic use.

Matropin is for topical ophthalmic use only and must not be injected or taken orally. To administer:

• Wash hands thoroughly before use.
• Tilt the head back and gently pull down the lower eyelid to form a small pocket.
• Instill the prescribed number of drops into the conjunctival sac without letting the dropper tip touch the eye, eyelid, or any surface.
• Close the eye gently and apply light pressure over the inner corner of the eye (nasolacrimal duct) for 1–2 minutes to reduce systemic absorption, especially in children.
• If wearing contact lenses, remove them before instillation and wait as advised before reinserting.

Clinically significant interactions with Matropin include:

• Other anticholinergic/antimuscarinic agents (e.g., oral antihistamines, tricyclic antidepressants, other belladonna alkaloids): concurrent use with Matropin can have additive systemic anticholinergic effects (dry mouth, tachycardia, urinary retention, confusion), particularly in children and the elderly.
• Miotic agents used for glaucoma (e.g., pilocarpine, carbachol): these have pharmacologically opposing effects to Matropin and concurrent use may reduce the intended effect of either drug; such combinations should only be used under specialist supervision.

Local (ocular) side effects

• Transient blurred vision and photophobia (light sensitivity)
• Stinging or burning sensation on instillation
• Ocular dryness or irritation
• Increased intraocular pressure in predisposed individuals

Systemic side effects (more likely with excessive use, in children, or without punctal occlusion)

• Dry mouth, flushing of the skin, fever
• Tachycardia (rapid heartbeat)
• Urinary retention
• Confusion, restlessness, or drowsiness, particularly in young children and elderly patients
• Skin rash

Pregnancy: There are no well-controlled studies establishing the safety of Matropin in human pregnancy. Because Matropin is applied topically to the eye with limited systemic absorption when used correctly, systemic fetal exposure is expected to be low, but Matropin should be used during pregnancy only if clearly needed and the potential benefit justifies the potential risk to the fetus. Consult a physician before use.

Lactation: It is not known whether Matropin is excreted in human breast milk. Caution is advised, and a physician should be consulted before using Matropin while breastfeeding.

• Use Matropin with caution in infants and young children, who are more susceptible to systemic anticholinergic toxicity (flushing, fever, tachycardia, dry mouth); use the lowest effective concentration and apply punctal occlusion after instillation.
• Use with caution in elderly patients, who have an increased risk of undiagnosed narrow anterior chamber angles and angle-closure glaucoma (see Contraindications).
• Patients with Down syndrome may show increased pupillary sensitivity to mydriatic agents such as Matropin; use the lowest effective dose.
• Matropin causes temporary blurred vision and photophobia; advise patients not to drive or operate machinery until vision returns to normal, and to wear sunglasses to reduce light sensitivity.
• Avoid touching the dropper tip to the eye or any surface to prevent contamination.
• Remove soft contact lenses before instillation.

Excessive ocular or accidental systemic exposure to Matropin may cause signs of systemic anticholinergic toxicity, including flushing, fever, dry mouth and skin, rapid heartbeat, urinary retention, restlessness, agitation, or hallucinations, and in severe cases, seizures. If overdose or accidental ingestion is suspected, seek immediate medical attention or contact a poison control center right away; do not attempt to manage severe symptoms at home.

Store at room temperature (below 30°C), away from light and moisture. Keep the bottle tightly closed and out of reach of children. Discard any unused solution per the expiry date and, once opened, within the period recommended on the label.

• Pediatric patients: Matropin should be used with caution in infants and young children due to increased susceptibility to systemic anticholinergic effects; use the lowest effective concentration (typically 2%) and minimize systemic absorption with punctal occlusion. Safety and efficacy in neonates have not been well established.
• Elderly patients: Use with caution due to a higher likelihood of undiagnosed narrow anterior chamber angles, which increases the risk of drug-induced angle-closure glaucoma; also monitor for confusion or other systemic anticholinergic effects.
• Hepatic/renal impairment: No specific dose adjustment data are established for ophthalmic Matropin, given its limited systemic absorption when administered correctly; use with routine caution.

For diagnostic mydriasis/cycloplegia, Matropin is typically used as a single dose or brief dosing session on the day of examination. For treatment of anterior uveitis or iritis, Matropin is generally continued for the short term (days to a few weeks) at the discretion of the treating ophthalmologist, with regular reassessment of inflammation and tapering as symptoms improve.

Homatropine Hydrobromide is classified under: Anticholinergics (Antimuscarinics); Ophthalmic mydriatics; Ophthalmic cycloplegics.

Homatropine Hydrobromide competitively blocks muscarinic acetylcholine receptors on the iris sphincter and ciliary muscle. This antagonism relaxes the iris sphincter (producing mydriasis/pupil dilation) and paralyzes the ciliary muscle (producing cycloplegia/loss of accommodation), which together enable accurate ophthalmic examination and reduce pain and complications associated with ciliary spasm in anterior uveitis.

Matropin can be used in pediatric patients for diagnostic mydriasis/cycloplegia and for adjunctive treatment of anterior uveitis, but children — especially infants and young children — are more susceptible to systemic anticholinergic toxicity (flushing, fever, tachycardia, dry mouth) than adults. The lowest effective concentration (typically 2%) should be used, punctal occlusion applied after instillation, and children observed for systemic signs of toxicity. Safety and efficacy of Matropin in neonates have not been well established, and its use in this age group should be under close specialist supervision only.