Homatropine hydrobromide is an ophthalmic, cycloplegic mydriatic agent. It is used for cycloplegic refraction and for dilating the pupil in inflammatory conditions of the uveal tract. It is also used for pre- and postoperative mydriasis, iritis, ciliary spasm, as an aid in axial lens opacities and as a provocative agent in the diagnosis of open-angle glaucoma. Homatropine is an inferior cycloplegic when compared to ophthalmic atropine or cyclopentolate, particularly in children. Homatropine has a longer duration of action than tropicamide or cyclopentolate, but a shorter duration than atropine or scopolamine. Homatropine hydrobromide was approved by the FDA pre-1938.
General Administration Information
For storage information, see the specific product information within the How Supplied section.
Route-Specific Administration
Ophthalmic Administration
-For ophthalmic use only. Do not allow the product to get into the mouth.
-Wash hands before and after use.
-Tilt the head back slightly and pull the lower eyelid down with the index finger to form a pouch. Squeeze the prescribed number of drops into the pouch and close eyes for 1-2 minutes. Do not blink. Gently apply pressure to the inner corner of the eye for 1-2 minutes to prevent excessive systemic absorption.
-Care should be taken to avoid contamination. Do not touch the tip of the dropper to the eye, fingertips, or other surface. Use only one open bottle per patient.
Cardiovascular adverse effects would not be expected with normal ocular dosages of homatropine. However, if the drug is absorbed systemically to any significant degree, cardiovascular adverse reactions might occur. Sinus bradycardia and sinus tachycardia have been reported. Of note, a rapid and irregular pulse may be an indication of homatropine toxicity. Closely monitor patients; administration of parenteral physostigmine may be particularly useful in cases of arrhythmias resulting in uncontrolled hemodynamic instability. However, atropine poisoning is rarely fatal, even with large doses, and is self-limited if the cause is recognized and the homatropine medication is discontinued. Supportive measures should be instituted. For ingestion, activated charcoal can be used to prevent drug absorption. If necessary, ipecac or another cathartic may be useful for drug removal during initial treatment. Physostigmine is used as an antidote to the systemic effects and may be administered parenterally to provide more prompt relief of intoxication.
Transient ocular pain (reported as stinging and burning) may occur upon instillation of homatropine; blurred vision will occur within 30-90 minutes. Patients should be warned about driving or performing hazardous activities while the pupils are dilated. Photophobia will also occur and patients should wear protective sunglasses while in bright light. Local ocular irritation that was not present before therapy, follicular conjunctivitis, vascular congestion, edema, exudate, and eczematoid dermatitis may also occur; cycloplegia and mydriasis may last from 2-4 days.
Homatropine hydrobromide solution is usually free of adverse effects if used in standard ophthalmologic doses, although thirst or xerostomia may occur. However, anticholinergic toxicity (including ataxia, confusion, delirium, aggressive behavior, agitation, dysarthria, restlessness, excitability, and hallucinations) has been reported in both pediatric and geriatric patients following administration of homatropine eye drops. Mania and hallucinations have been reported due to systemic absorption of normal as well as excessive doses of homatropine. In children < 6 years of age, seizures, drowsiness, fever, and coma may be the presenting symptoms. Anticholinergic psychosis results from competitive inhibition of acetylcholine on central muscarinic receptor sites. Toxic symptoms may occur in minutes to hours and include dry skin, rash (unspecified) (more likely in children), abdominal distention (in infants), mental aberration (hallucinations), dry mouth (xerostomia), flushing, fever, unresponsive and dilated pupils, blurred vision, photophobia, urinary retention, loss of neuro-muscular coordination, and tachycardia. Atropine poisoning is rarely fatal, even with large doses, and is self-limited if the cause is recognized and the homatropine medication is discontinued. Institute supportive measures, including maintaining a patent airway and assisting respiration if needed. Treat hyperthermia, coma, and seizures if they occur. In infants and children, the body surface must be kept moist. Excitement may be controlled by diazepam or a short-acting barbiturate. For ingestion, activated charcoal can be used to prevent drug absorption. If necessary, ipecac or another cathartic may be useful for drug removal during initial treatment. Physostigmine is used as an antidote to the systemic effects and may be administered parenterally to provide more prompt relief of intoxication. Parenteral physostigmine (1-2 mg given slowly by subcutaneous or intravenous route) may be particularly useful in cases of pronounced hallucinations, agitation in which a patient may be dangerous to himself or others, and intractable seizures. Discontinuation of homatropine resulted in recovery within 6-24 hours in most cases.
Ocular hypertension is an expected side effect with the use of homatropine hydrobromide. Increased intraocular pressure occurred in 73% of 70 glaucomatous eyes and 15% of 140 normal eyes. Homatropine hydrobromide should not be used in patients with open- or closed-angle glaucoma, or a propensity for narrow angles.
Contact dermatitis to homatropine has been reported in one case involving an ophthalmology nurse. As part of her job, she applied the solution topically to patient's eyes. Over a 3-year period, she developed pruritic and erythematous facial contact dermatitis. She had never used homatropine ophthalmic solution herself. After leaving the field of ophthalmology, her contact dermatitis resolved. Cross-sensitivity with atropine may also occur.
The use of homatropine is contraindicated in patients with a previous hypersensitivity to any of the ingredients of the ophthalmic preparation. Patients who have exhibited belladonna alkaloids hypersensitivity may be cross-sensitive to homatropine hydrobromide and the product should be used cautiously, if at all. Cautious use is also recommended in patients previously sensitive to atropine or scopolamine. If sensitivity should occur, patients should discontinue the medication and contact their health care provider.
Homatropine is contraindicated in patients with open-angle glaucoma or closed-angle glaucoma. To avoid inducing angle-closure glaucoma, an estimate of the depth of the angle of the anterior chamber should be made in patients suspected of having a narrow anterior chamber angle. Inhibition of the ciliary muscle may result in obstruction of aqueous outflow and subsequent increased intraocular pressure.
The manufacturer recommends that homatropine hydrobromide be used with extreme caution in neonates, infants and children < 6 years of age; other mydriatic medications may be preferred. Anticholinergic adverse effects from systemic absorption have also occurred in older children and even healthy adults. Central and peripheral anticholinergic toxicity, including psychosis, may occur. In children, retrograde amnesia may be present after recovery of the acute phase. Mydriasis and cycloplegia may persist for several days.
Patients with documented renal disease, renal impairment or renal failure may be more prone to accumulation of homatropine ophthalmic solution and accompanying anticholinergic toxicity. The elderly in particular may be at greater risk. Homatropine should be used cautiously in these patient populations.
Patients should be warned about driving or operating machinery while the pupils are dilated following homatropine instillation. Patients should also protect eyes from bright light while the eyes are dilated. Cycloplegia and mydriasis may last up to 3 days.
Homatropine hydrobromide is classified in FDA pregnancy risk category C. There are no well-controlled studies in pregnant women. According to the manufacturer, homatropine should be used in pregnancy only when the benefits clearly outweigh the risks. Limited epidemiologic data report that the frequency of congenital anomalies was no greater than expected among the infants of women treated with homatropine during the first trimester of pregnancy; a possible association has been noted in other groups treated throughout pregnancy.
According to the manufacturer, homatropine should be used cautiously in women who are breast-feeding their infants. It is not known whether the drug is excreted in human milk. The American Academy of Pediatrics (AAP) has not evaluated homatropine but considers atropine to be usually compatible with breast-feeding. Anticholinergic medications have been associated with a reduction in milk production. Although a single dose of ophthalmic homatropine is not likely to have any adverse effects on lactation, it is not clear whether chronic use may impact milk production. To minimize the amount of drug that reaches the systemic circulation and breast milk, apply pressure over the tear duct by the corner of the eye for 1 minute after ophthalmic administration. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally ingested drug, healthcare providers are encouraged to report the adverse effect to the FDA.
Patients with hypertension or cardiac disease may be at greater risk of adverse effects with systemic absorption of homatropine. Bradycardia as well as tachycardia have been reported with homatropine use.
The anticholinergic effects of homatropine may make the eyes dry. This can cause an increased lens awareness, or blurred vision for wearers of contact lenses. Contact lenses should only be worn during homatropine use if recommended by the health care provider.
Significant systemic absorption has been reported with ocular homatropine. Adverse effects, similar to those seen with atropine may occur. Homatropine should be used cautiously in persons with GI infection or infectious diarrhea due to the possibility for decreased GI motility. Also, use homatropine cautiously in patients with GI obstruction, severe gastroesophageal reflux disease (GERD), ulcerative colitis, paralytic ileus, and intestinal atony because homatropine may decrease GI motility and can exacerbate these conditions.
Geriatric patients should be monitored carefully due to an increased susceptibility to anticholinergic effects from ophthalmic homatropine. Anticholinergic adverse effects from systemic absorption have occurred, even in healthy adults. The anticholinergic effects of homatropine may be significant and are additive with other anticholinergic medications, particularly in the older adult. In nursing home residents, health care providers should be careful not to confuse anticholinergic mental status changes with those of the current diagnosis, such as Alzheimer's disease or dementia.
For mydriasis induction and cycloplegia induction for refraction:
Ophthalmic dosage (5% ophthalmic solution):
Adults: 1 or 2 drops in the affected eye(s); may repeat dose in 5 to 10 minutes if necessary.
For the treatment of uveitis:
Ophthalmic dosage (5% ophthalmic solution):
Adults: 1 or 2 drops in the affected eye(s) up to every 3 to 4 hours. Individuals with heavily pigmented irides may require larger doses.
Maximum Dosage Limits:
-Adults
16 drops/eye/day.
-Geriatric
16 drops/eye/day.
-Adolescents
Safety and efficacy have not been established.
-Children
Safety and efficacy have not been established.
-Infants
Safety and efficacy have not been established.
-Neonates
Safety and efficacy have not been established.
Patients with Hepatic Impairment Dosing
Specific guidelines for dosage adjustments in hepatic impairment are not available; it appears that no dosage adjustments are needed.
Patients with Renal Impairment Dosing
Specific guidelines for dosage adjustments in renal impairment are not available; however, if homatropine ophthalmic solutions are systemically absorbed to any great degree, patients with renal impairment may be at risk of anticholinergic toxicity. Lower dosages may be indicated.
*non-FDA-approved indication
There are no drug interactions associated with Homatropine Hydrobromide products.
Homatropine, a belladonna alkaloid, has an anticholinergic effect that blocks the responses of the sphincter muscle of the iris and the muscle of the ciliary body to cholinergic stimulation. Mydriasis (pupil dilation) and cycloplegia (paralysis of accommodation) are the resulting physiologic effects. Mydriasis is often needed for examination of the retina and optic disc and for treatment of acute inflammatory conditions of the iris and uveal tract. Cycloplegia is needed for measurement of refractive errors and following cataract surgery.
Pharmacokinetics:
Homatropine hydrobromide is administered as an ophthalmic solution.
-Route-Specific Pharmacokinetics
Other Route(s)
Ophthalmic route
Topical administration does not usually result in significant systemic absorption, but toxic effects have been reported. The absorption occurs via diffusion through the cornea and conjunctiva, as well as through tears from the nasolacrimal ducts. The maximum mydriatic effect occurs within 10-30 minutes and the maximum cycloplegic effect occurs within 30-90 minutes. Mydriasis may persist for 6 hours to 4 days, and cycloplegia may persist for 10 hours to 3 days following instillation.