Understanding Homatropine and Its Role in Medicine
Homatropine is an antimuscarinic drug, primarily used in ophthalmology as an eye drop to dilate the pupil (mydriasis) and temporarily paralyze the eye's focusing muscles (cycloplegia) [1.7.5, 1.7.6]. These actions are crucial for certain diagnostic eye examinations, allowing ophthalmologists to get a clear view of the retina and internal structures of the eye [1.7.2]. It is also used therapeutically in the management of anterior uveitis, an inflammatory condition of the eye, to relieve pain from ciliary muscle spasms and prevent the iris from adhering to the lens [1.7.6]. Homatropine is a semi-synthetic derivative of atropine and acts as a competitive inhibitor of acetylcholine at muscarinic receptors [1.6.4, 1.7.1]. Its effects have a faster onset and shorter duration than atropine, typically lasting 1 to 3 days, making it a preferred agent in some clinical scenarios [1.7.5, 1.8.3].
So, Has Homatropine Been Discontinued?
The answer to this question is nuanced. Several specific formulations and brands of homatropine have indeed been discontinued. Notably, the Isopto Homatropine brand name is no longer available in the United States [1.2.1, 1.4.1]. Similarly, Alcon discontinued Isopto Homatropine 2% eye drops in Australia for financial reasons [1.4.5]. The Therapeutic Goods Administration (TGA) of Australia officially cancelled this product in 2017 [1.4.4].
Furthermore, the FDA's drug shortage database has listed discontinuations for other products containing a form of homatropine. For instance, a combination tablet of hydrocodone bitartrate and homatropine methylbromide was noted as discontinued for business reasons [1.2.2, 1.5.4]. A syrup formulation containing these ingredients was also slated for discontinuation on September 11, 2025 [1.5.2].
However, the discontinuation of these specific products does not mean homatropine is entirely unavailable. The FDA has stated that if generic versions have been approved, they may be available for patients [1.2.1]. Products such as Homatropaire, a 5% ophthalmic solution, are still listed by some suppliers, though availability can be limited to licensed eye care professionals [1.3.6, 1.3.2]. The FDA also maintains that some homatropine products have not been found to be safe and effective, and their labeling has not been approved, adding another layer of complexity to their market status [1.2.5, 1.2.6]. Therefore, while major brands are gone, generic and other formulations may still be accessible through specific channels.
Pharmacological Profile and Clinical Use
Homatropine works by blocking muscarinic receptors in the eye's sphincter and ciliary muscles [1.7.6]. This blockage prevents the pupil from constricting and paralyzes accommodation. The peak effect for mydriasis occurs in about 10-30 minutes, with cycloplegia occurring in 30-90 minutes [1.7.5].
Primary uses include:
- Cycloplegic Refraction: To accurately determine a person's refractive error by preventing the eye from focusing.
- Uveitis Treatment: To manage pain and prevent complications like posterior synechiae.
- Pre- and Post-operative Care: Used before certain eye surgeries to widen the pupil or after to manage inflammation [1.3.5].
Common side effects are mostly related to its intended action, including blurred vision and sensitivity to light (photophobia). Systemic side effects like dry mouth or increased heart rate can occur but are less common [1.7.2]. It is contraindicated in patients with narrow-angle glaucoma [1.7.2].
Comparison of Homatropine and Its Alternatives
With the discontinuation of some homatropine products, clinicians often turn to alternatives. The most common are atropine, cyclopentolate, and tropicamide. Each has a different profile regarding onset and duration of action.
| Feature | Homatropine | Atropine | Cyclopentolate | Tropicamide |
|---|---|---|---|---|
| Primary Use | Uveitis, Cycloplegic Refraction [1.7.6] | Uveitis, Amblyopia Treatment [1.6.3] | Cycloplegic Refraction [1.8.3] | Diagnostic Dilation [1.8.3] |
| Onset of Action | 10–30 minutes [1.7.5] | ~40 minutes [1.8.4] | ~30 minutes [1.8.3] | 20–40 minutes [1.8.3] |
| Duration of Effect | 1–3 days [1.8.3] | 7–10 days [1.6.3, 1.7.5] | 6–24 hours [1.8.3] | 4–6 hours [1.8.3] |
| Potency | Weaker than atropine [1.8.3] | Most potent cycloplegic [1.8.5] | Strong cycloplegic effect [1.8.5] | Weak cycloplegic effect [1.8.3] |
Atropine is the most powerful agent with the longest duration, making it suitable for severe inflammation but less practical for routine exams [1.8.5]. Cyclopentolate has become a standard of care for pediatric refractions due to its strong effect and relatively short 24-hour duration [1.8.5]. Tropicamide has the shortest duration, making it ideal for diagnostic purposes where a quick recovery is desired [1.8.3].
Conclusion
The question 'Has homatropine been discontinued?' has a mixed answer. While major brands like Isopto Homatropine and certain combination products are officially off the market due to business decisions, the core drug may still be found in generic or alternative formulations like Homatropaire [1.2.1, 1.4.5, 1.3.6]. The landscape of ophthalmic cycloplegic and mydriatic agents is dynamic, with reliable alternatives like atropine, cyclopentolate, and tropicamide widely available to serve similar clinical needs [1.6.1, 1.8.3]. Patients and practitioners should verify the availability of specific products and consider the clinical context when choosing an appropriate agent.
For the most current information on drug availability, consulting the FDA's drug database is recommended.
Authoritative Link: For official information on drug status, you can search the FDA's Drug Database.
