Related Experiment Video
Updated: Jun 22, 2026
09:10
Direct-Coupled Electroretinogram (DC-ERG) for Recording the Light-Evoked Electrical Responses of the Mouse Retinal Pigment Epithelium
Published on: July 14, 2020
Diphenhydramine as a topical ocular anesthetic
Phillip J Suffridge1, Michael N Wiggins, Reid D Landes
1United States Air Force, Little Rock Air Force Base, Little Rock, Ark., USA.
Summary
Topical 5% diphenhydramine solution effectively anesthetized rabbit corneas for up to 90 minutes. This study suggests diphenhydramine may be a safe topical anesthetic option for patients with multiple allergies.
Area of Science:
- Ophthalmology
- Pharmacology
Background:
- Topical anesthetics are crucial in ophthalmology.
- Patients with multiple allergies may have limited anesthetic options.
Purpose of the Study:
- To evaluate the anesthetic effect of topical 5% diphenhydramine solution on rabbit corneas.
- To assess the safety and potential toxicity of topical diphenhydramine.
Main Methods:
- An experimental study was conducted on 20 New Zealand rabbits.
- Corneal sensation was measured using a Cochet-Bonnet esthesiometer after topical application of 5% diphenhydramine or balanced salt solution.
- Ocular toxicity was assessed via slit-lamp examination and fluorescein/Rose Bengal staining.
Main Results:
- 5% diphenhydramine solution demonstrated significant corneal anesthesia at 30, 60, and 90 minutes post-instillation.
- Mild conjunctival injection was observed in treated eyes.
- No corneal epithelial toxicity was detected.
Conclusions:
- Topical 5% diphenhydramine exhibits a significant anesthetic effect on rabbit corneas compared to a saline control.
- Diphenhydramine may serve as a safe alternative topical anesthetic for allergic patients.
- Further research is warranted to establish dose-response and human corneal safety.
Related Concept Videos
01:23Local Anesthetics: Common Agents and Their Applications
Local anesthetics (LAs) are commonly used for various applications in medical and dental procedures. Some of the common agents used are cocaine, lidocaine, and bupivacaine.
Cocaine is an ester of benzoic acid and methylecgogine. It is used to anesthetize and vasoconstrict locally. Currently, it is used primarily for topical applications. It is beneficial for surgeries on the upper respiratory tract, providing anesthesia and shrinking the mucosa. Cocaine in the form of cocaine hydrochloride is...
Cocaine is an ester of benzoic acid and methylecgogine. It is used to anesthetize and vasoconstrict locally. Currently, it is used primarily for topical applications. It is beneficial for surgeries on the upper respiratory tract, providing anesthesia and shrinking the mucosa. Cocaine in the form of cocaine hydrochloride is...
01:23Ophthalmic Drug Delivery Systems
Ophthalmic drug delivery faces major limitations due to poor absorption across the corneal membrane. This process is primarily driven by diffusion and is influenced by two main factors: the physicochemical properties of the drug and tear drainage. Most ophthalmic drugs, such as pilocarpine, epinephrine, atropine, and local anesthetics, are weak bases. They are typically formulated at an acidic pH to enhance chemical stability. However, this leads to high ionization, reducing their ability to...
01:30Local Anesthetics: Chemistry and Structure-Activity Relationship
Local anesthetics (LAs) are drugs that induce a temporary loss of sensation in a limited body area, preventing pain. Cocaine was the first local anesthetic discovered in the late 19th century. Cocaine is a benzoic acid ester obtained from the leaves of coca shrubs and was often used for its psychotropic effects. Cocaine was first isolated in 1860 by Albert Niemann. Sigmund Freud studied the physiological actions of cocaine. Carl Koller later introduced it into clinical practice in 1884 as a...
01:27Open Angle Glaucoma: Treatment
In open-angle glaucoma, the iridocorneal angle remains open, but the trabecular meshwork becomes stiff, slowing down the outflow of aqueous humor. This causes a buildup of aqueous humor in the anterior chamber, leading to a sudden increase in intraocular pressure. The treatment for open-angle glaucoma focuses on reducing the elevated intraocular pressure by either decreasing the secretion of aqueous humor or increasing its outflow.
Drugs such as carbonic anhydrase inhibitors, α2- and...
Drugs such as carbonic anhydrase inhibitors, α2- and...
01:29Local Anesthetics: Clinical Application as Epidural Anesthesia
Epidural anesthetics are administered in the fat-filled epidural space, the outermost part of the spinal canal. This technique is commonly employed for pain management and anesthesia during lower abdomen and pelvis surgeries or labor and delivery.
Since epidural anesthetics can be infused through an epidural catheter, all types of drugs, including short-acting ones, can be administered. Chloroprocaine and lidocaine are examples of short and long-duration anesthetics, respectively. Bupivacaine...
Since epidural anesthetics can be infused through an epidural catheter, all types of drugs, including short-acting ones, can be administered. Chloroprocaine and lidocaine are examples of short and long-duration anesthetics, respectively. Bupivacaine...
01:30Local Anesthetics: Clinical Application as Surface, Infiltration, and Conduction Block Anesthesia
Depending on the target organ, local anesthetics (LAs) can be administered via various routes. In surface anesthesia, LAs are applied directly to the surface of the skin or mucous membranes. It is widely used for topical skin numbing before venipuncture or minor surgical procedures. Commonly used surface local anesthetics are lidocaine or benzocaine sprays or creams. Surface anesthesia occurs within 5 minutes and lasts for about 60 minutes. One of the main disadvantages of topical anesthesia is...