Homatropine

Pronunciation: hoh-MAT-roh-peen.

Generic name
homatropine hydrobromide (ophthalmic); hydrocodone bitartrate/homatropine methylbromide (oral combination)
Drug class
Anticholinergic mydriatic/cycloplegic (ophthalmic); opioid antitussive combination with an anticholinergic abuse-deterrent (oral)
Form
Ophthalmic solution (eye drops); oral tablet or oral solution/syrup (in combination with hydrocodone)
Route
Ophthalmic (eye drops) or oral (tablet/syrup), depending on the product
Legal status
Prescription-only in both forms; the oral combination is additionally a Schedule II controlled substance in the United States

Availability and supply rules vary by country

Trade names by country: United States · Canada · Australia

Australia: Isopto Homatropine (historic; cancelled 2017) (7) · Full directory

What homatropine hydrobromide (ophthalmic); hydrocodone bitartrate/homatropine methylbromide (oral combination) is and how it works

Homatropine is an anticholinergic medicine used in two very different ways. As an eye drop (homatropine hydrobromide ophthalmic solution), it temporarily dilates the pupil and relaxes the eye's focusing muscle, used for eye examinations and to treat inflammation inside the eye (uveitis). As homatropine methylbromide, it is combined in a small, non-treatment dose with the opioid hydrocodone in an oral cough medicine -- the homatropine there is included specifically to discourage people from taking too much of the opioid component, not to treat the cough itself. (1) (2)

Always confirm which of these two very different products you have been prescribed. The eye drop can cause genuine systemic (whole-body) anticholinergic toxicity in infants and young children if overused or if the eye is not properly cared for after application. The oral cough combination contains an opioid and carries a real, current, boxed-warning-level risk of serious breathing problems, addiction, and interactions with other sedating medicines or alcohol.

Mechanism of action: how homatropine hydrobromide (ophthalmic); hydrocodone bitartrate/homatropine methylbromide (oral combination) works

Homatropine is a semisynthetic anticholinergic (muscarinic antagonist). In the ophthalmic form, it blocks the iris sphincter and ciliary muscle's response to cholinergic stimulation, producing mydriasis (pupil dilation) and cycloplegia (paralysis of accommodation). In the oral combination, homatropine methylbromide is present at a low, non-mydriatic/non-cycloplegic dose specifically to produce unpleasant anticholinergic effects (such as dry mouth and blurred vision) if the opioid component is taken in excess, discouraging deliberate overdosage -- it plays no role in suppressing the cough itself, which is hydrocodone's action as a centrally-acting opioid antitussive. (1) (2)

What homatropine hydrobromide (ophthalmic); hydrocodone bitartrate/homatropine methylbromide (oral combination) is used for

Eye examinations (cycloplegic refraction) -- ophthalmic form

Used to temporarily dilate the pupil and relax the eye's focusing (accommodative) muscle so an eye care professional can examine the back of the eye or measure the eye's true refractive error. (1)

Uveitis and other inflammatory eye conditions -- ophthalmic form

Used to treat inflammation of the uveal tract (uveitis) and, before or after eye surgery, when pupil dilation is needed. (1)

Cough suppression -- oral hydrocodone/homatropine combination

Used to relieve cough in adults. Homatropine itself does not treat the cough -- it is included at a low, non-treatment dose specifically to discourage taking more of the opioid (hydrocodone) component than prescribed. (2)

Before taking homatropine hydrobromide (ophthalmic); hydrocodone bitartrate/homatropine methylbromide (oral combination)

Do not take / not appropriate for

  • Do not use homatropine eye drops if you have, or are at risk of, angle-closure glaucoma (including a narrow anterior-chamber angle), or a known allergy to any ingredient in the drops. (ophthalmic form, all countries) (1)
  • Homatropine eye drops should not be used in infants under 3 months of age because of the risk of inducing amblyopia (reduced vision development). (ophthalmic form, all countries) (1)
  • Do not take the oral hydrocodone/homatropine combination if you have significant breathing problems, a blocked or narrowed gastrointestinal tract, or a known allergy to hydrocodone or homatropine. (oral combination, United States) (2)

Tell your clinician about

  • For the eye drop: any history of glaucoma or narrow-angle eyes, and the age of the person being treated (infants and young children need extra care).
  • For the oral combination: any breathing conditions (such as asthma or COPD), any history of substance use disorder, all other medicines that cause drowsiness (including benzodiazepines, other sedatives, and alcohol use), and whether you are pregnant or breastfeeding.
  • Which specific product you have been prescribed -- the eye drop and the oral cough combination are managed completely differently.
(1) (2)

How to take homatropine hydrobromide (ophthalmic); hydrocodone bitartrate/homatropine methylbromide (oral combination)

  • Ophthalmic form: instill only the number of drops directed by your eye care professional, and gently press on the inner corner of the eye near the nose (the lacrimal sac) for 2-3 minutes after each drop to reduce the amount absorbed into the rest of the body -- this is especially important for infants, young children, and older adults.
  • Oral combination: take exactly as prescribed, using a proper measuring device for liquid forms -- ask your pharmacist for one if you do not have one. Do not take more than prescribed, more often than prescribed, or for longer than prescribed.
  • Do not drive or operate machinery after either product until you know how it affects you -- the oral combination in particular can cause significant drowsiness.
(1) (2)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4) (5) (6) (7) (8)

Missed dose

Contact your prescriber or pharmacist for guidance on a missed dose of either product. Do not take an extra dose of the oral hydrocodone/homatropine combination to make up for a missed one -- this increases the risk of dangerous respiratory depression.

Overdose

For the oral combination: seek emergency medical help immediately if too much has been taken, or if severe drowsiness, slow or difficult breathing, pinpoint pupils, or loss of consciousness develop -- this can be fatal. For the eye drops: seek urgent medical attention if a child has been overexposed and develops flushing, fever, rapid heartbeat, dry mouth, or unusual behaviour (signs of systemic homatropine poisoning). (2) (1)

Side effects

Side effects and their urgency vary; report severe, persistent, or concerning symptoms.

Eye drops: transient stinging or burning on instillation; with prolonged use, eye irritation, conjunctivitis, eyelid swelling, or contact dermatitis; sensitivity to light and dry mouth can occur from systemic absorption.

What to notice: Eye drops: transient stinging or burning on instillation; with prolonged use, eye irritation, conjunctivitis, eyelid swelling, or contact dermatitis; sensitivity to light and dry mouth can occur from systemic absorption.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Oral combination: drowsiness, dizziness, nausea, constipation, and dry mouth are common opioid/anticholinergic-type effects.

What to notice: Oral combination: drowsiness, dizziness, nausea, constipation, and dry mouth are common opioid/anticholinergic-type effects.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (2)

Serious warnings

Signs of systemic homatropine poisoning after eye drop use, especially in infants and young children — high_caution

Symptoms: Flushed, hot, dry skin, fever, unusually fast heartbeat, marked dry mouth, or confusion/unusual behaviour after eye drop use.

Action: Seek urgent medical attention. Excessive or repeated dosing of homatropine eye drops -- or not compressing the inner corner of the eye after instillation -- can allow enough of the drug to be absorbed into the whole body to cause this reaction, which is why careful technique and dosing are especially important in infants, young children, and older adults. (1)

Signs of angle-closure glaucoma after eye drop use — high_caution

Symptoms: Sudden eye pain, blurred vision, halos around lights, nausea, or a red eye after using the drops.

Action: Seek emergency eye care immediately -- this is why an eye care professional checks the anterior chamber angle before prescribing homatropine eye drops. (1)

Signs of serious breathing problems from the oral hydrocodone/homatropine combination — boxed_warning

Symptoms: Slow, shallow, or difficult breathing; extreme drowsiness or inability to wake up; blue-tinged lips or fingertips.

Action: Seek emergency medical help immediately -- this reflects the current US FDA boxed warning for life-threatening respiratory depression with this opioid-containing combination, especially at the start of treatment or after a dose increase. (2)

Accidental ingestion by a child — boxed_warning

Symptoms: Any suspected or known ingestion of the oral hydrocodone/homatropine combination by a child, even a small amount.

Action: Seek emergency medical help immediately -- accidental ingestion of this opioid-containing medicine by a child can be fatal, which is why it must always be stored safely out of reach. (2)

Interactions

  • Eye drops: other anticholinergic medicines may add to systemic anticholinergic effects; caution advised if used alongside other medicines with similar effects. (1)
  • Oral combination: benzodiazepines, other central nervous system depressants (including other opioids, sedatives, and some antihistamines), and alcohol can all dangerously increase the risk of severe drowsiness and respiratory depression when combined with this opioid-containing medicine. (2)
  • Oral combination: medicines that affect the CYP3A4 liver enzyme (either strong inhibitors or inducers) can significantly change hydrocodone blood levels, requiring dose adjustment or closer monitoring by the prescriber. (2)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy

Oral combination: prolonged use during pregnancy can cause neonatal opioid withdrawal syndrome in the newborn, which can be life-threatening if not recognised and treated; discuss any opioid use in pregnancy with your prescriber. Eye drops: use only if clearly needed, under an eye care professional's guidance. (1) (2) (3) (4) (5) (6) (7) (8)

Breastfeeding

Discuss with your prescriber for either product -- the oral combination's opioid component in particular needs individualised risk-benefit discussion during breastfeeding. (1) (2) (3) (4) (5) (6) (7) (8)

Children

Eye drops: used with particular care in infants and young children because of the systemic absorption/toxicity risk described above; not used under 3 months of age. Oral combination: paediatric use requires specialist opioid-prescribing judgement given the same class-wide risks as in adults, magnified in children. (1) (2) (3) (4) (5) (6) (7) (8)

Elderly

Eye drops: older adults are more susceptible to systemic anticholinergic toxicity, so careful technique (lacrimal sac compression) and dosing matter particularly here. Oral combination: increased sensitivity to opioid sedation and respiratory depression is common in older adults. (1) (2) (3) (4) (5) (6) (7) (8)

Monitoring

Before starting

  • Eye drops: anterior chamber angle assessment to rule out angle-closure glaucoma risk; confirmation of age (avoid under 3 months)
  • Oral combination: breathing status, substance-use history, and a review of all other sedating medicines/alcohol use

During treatment

  • Eye drops: watch for local irritation and, in infants/young children, any sign of systemic anticholinergic toxicity.
  • Oral combination: monitor for excessive sedation or slowed breathing, especially at treatment start or after a dose change; monitor for signs of misuse/dependence over time.
(1) (2)

Storage

Store both products at room temperature, away from light and moisture, out of reach of children -- the oral hydrocodone/homatropine combination is an opioid and must be stored securely (e.g. in a locked cabinet) precisely because of the accidental-ingestion risk described in the boxed warning.

Professional information

Clinician-facing context only, sourced from current US FDA/DailyMed labeling for both products; verify against the current full label before prescribing, and confirm which specific product (ophthalmic vs. oral combination) applies.

United States (currently marketed)

Indication: Cycloplegic refraction / uveitis (ophthalmic)

Dose summary: 1-2 drops for refraction (may repeat at 5-10 minutes); 1-2 drops up to every 3-4 hours for uveitis; higher doses may be needed for heavily pigmented irides.

Renal context: The ophthalmic label gives no renal dose adjustment. Homatropine eye drops act topically on the eye with limited systemic exposure at recommended doses; renal status is judged by the prescriber rather than adjusted from a published table. Systemic anticholinergic effects are more likely in children and older adults, so use the smallest effective number of drops. (1)

United States (the only market this combination is confirmed currently marketed in)

Indication: Cough suppression (oral hydrocodone/homatropine combination)

Dose summary: Individualised, product-strength-dependent dosing (commonly 5 mg hydrocodone/1.5 mg homatropine per tablet or per 5 mL); Schedule II controlled substance prescribing rules apply.

Renal context: The ophthalmic label gives no renal dose adjustment. Homatropine eye drops act topically on the eye with limited systemic exposure at recommended doses; renal status is judged by the prescriber rather than adjusted from a published table. Systemic anticholinergic effects are more likely in children and older adults, so use the smallest effective number of drops. (2) (3)

Mechanism of action

Hepatic guidance

The ophthalmic label gives no hepatic dose adjustment.

Overdose note

Oral combination: manage as an opioid overdose (naloxone, respiratory support) with awareness that the anticholinergic homatropine component may also cause additional signs (dry mouth, flushing, tachycardia). Ophthalmic form: manage systemic anticholinergic toxicity with supportive care. (1) (2)

Frequently asked questions

Are the homatropine eye drops and the homatropine cough medicine the same thing?

No -- they are two different products that happen to share the name 'homatropine.' The eye drop (homatropine hydrobromide) dilates the pupil and relaxes eye focusing for exams and uveitis treatment. The oral cough medicine combines a much smaller dose of homatropine methylbromide with the opioid hydrocodone specifically to discourage taking too much of the opioid -- it does not treat cough on its own. Always confirm which one you have been prescribed. (1) (2)

Is homatropine ophthalmic solution available in the US, UK, Europe, Canada, Australia, and New Zealand?

It remains currently marketed in the United States (as Homatropaire). It has been discontinued in the United Kingdom (no current licensed product), in Canada (cancelled 2016), and in Australia (cancelled 2017 after the sponsor ceased supply). No European Union-wide source was found, and New Zealand's current status could not be confirmed -- both are honestly reported as unable to verify rather than assumed. (1) (5) (6) (7) (8)

Why does the oral cough medicine have a boxed warning?

Because it contains hydrocodone, an opioid, the oral hydrocodone/homatropine combination carries the current, class-wide US FDA boxed warning covering addiction/abuse/misuse, life-threatening respiratory depression, accidental ingestion (especially by children), medication errors, a CYP3A4 drug interaction, dangerous interactions with benzodiazepines/other CNS depressants/alcohol, and neonatal opioid withdrawal syndrome. This warning does not apply to the separate eye drop product, which contains no opioid. (2)

What is the mechanism of action of homatropine hydrobromide (ophthalmic); hydrocodone bitartrate/homatropine methylbromide (oral combination)?

Homatropine is a semisynthetic anticholinergic (muscarinic antagonist). In the ophthalmic form, it blocks the iris sphincter and ciliary muscle's response to cholinergic stimulation, producing mydriasis (pupil dilation) and cycloplegia (paralysis of accommodation). In the oral combination, homatropine methylbromide is present at a low, non-mydriatic/non-cycloplegic dose specifically to produce unpleasant anticholinergic effects (such as dry mouth and blurred vision) if the opioid component is taken in excess, discouraging deliberate overdosage -- it plays no role in suppressing the cough itself, which is hydrocodone's action as a centrally-acting opioid antitussive. (1) (2)

What is the generic name of Homatropine?

The generic name is homatropine hydrobromide (ophthalmic); hydrocodone bitartrate/homatropine methylbromide (oral combination). (1) (2)

What class of drug is homatropine hydrobromide (ophthalmic); hydrocodone bitartrate/homatropine methylbromide (oral combination)?

Homatropine is classed as: Anticholinergic mydriatic/cycloplegic (ophthalmic); opioid antitussive combination with an anticholinergic abuse-deterrent (oral). (1) (2)

References

  1. Homatropine Hydrobromide Ophthalmic Solution, USP 5% (Homatropaire) -- Altaire Pharmaceuticals, Inc.U.S. National Library of Medicine / DailyMed, full prescribing information · United States · accessed 2026-07-31 · source 1
  2. HYCODAN (hydrocodone bitartrate and homatropine methylbromide) -- FDA label (class-wide opioid boxed warning)U.S. Food and Drug Administration, full prescribing information · United States · accessed 2026-07-31 · source 2
  3. Hydrocodone/homatropine current US market status, 2026Aggregated US pharmacy/consumer drug reference (Drugs.com, GoodRx, Walgreens current listings) · United States · accessed 2026-07-31 · source 3
  4. Hydrocodone international availability -- predominantly a US-only medicineAggregated international drug-control literature (INCB; clinical pharmacology commentary) · Global / United Kingdom / European Union · accessed 2026-07-31 · source 4
  5. emc search for "homatropine" -- no results; homatropine eye drops confirmed discontinued in the UKelectronic medicines compendium (emc), United Kingdom · United Kingdom · accessed 2026-07-31 · source 5
  6. ISOPTO HOMATROPINE 2% -- DPD product record, DIN 00000779Health Canada Drug Product Database (DPD) · Canada · accessed 2026-07-31 · source 6
  7. ISOPTO homatropine hydrobromide 2% eye drops bottle -- ARTG entry 25353, cancelled by sponsorTherapeutic Goods Administration (TGA), Australia · Australia · accessed 2026-07-31 · source 7
  8. No current Medsafe data sheet or consent record confirmed for homatropine ophthalmic or the oral hydrocodone/homatropine combinationMedsafe (New Zealand regulator) -- search attempted, no confirming source found · New Zealand · accessed 2026-07-31 · source 8

Brand names by country

Single-ingredient homatropine hydrobromide (ophthalmic); hydrocodone bitartrate/homatropine methylbromide (oral combination) names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

  • Homatropaire (ophthalmic) (1)currently marketed confirmed 2026 · 5% · Altaire Pharmaceuticals, Inc.
  • Hydrocodone/homatropine (generic; historic brands Hycodan, Tussigon, Hydromet) (2) (3)generic currently marketed confirmed 2026 original brand discontinued 2008 · 5 mg/1.5 mg per tablet or per 5 mL · Various generic manufacturers

Canada

  • Isopto Homatropine (historic; cancelled 2016) (6)din cancelled post market 2016-04-14 · 2% · Alcon Canada Inc. (historic; DIN 00000779)

Australia

  • Isopto Homatropine (historic; cancelled 2017) (7)artg cancelled 2017-11-21 sponsor ceased supply · 2% · Alcon/Novartis Australia Pty Ltd (historic; ARTG 25353)
View brands in additional countries.

This page provides general reference information about homatropine (both the ophthalmic and oral combination forms) and is not a substitute for advice from the clinician managing your treatment. Always confirm which specific product you have been prescribed.

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