This week’s Pharmacy Phriday CE article will focus on tetracaine, a medication provided to assist in treating eye injuries. It is rarely used in the field, but it can be extremely helpful in specific cases.
Tetracaine is a rapid, short-acting topical local anesthetic ophthalmic solution referenced in the “Maxillofacial Trauma” protocol to treat pain associated with non-traumatic eye injuries that might include:
- Chemical burns in the eye.
- Flash burns from ultraviolet light produced from arc welders, tanning booths, the sun, etc.
- Foreign bodies in the eye, which cause irritation.
- To facilitate the use of the Morgan Lens device in flushing the eye after a chemical exposure.
For our anatomy and physiology enthusiasts, tetracaine works by blocking sodium channels, which prevents depolarization of nerves. This will cause a local anesthesia. More simply, the medication works by blocking the pain signals at the nerve endings in the eye. The onset of action usually occurs within 30 seconds and lasts about 15 minutes or less.
UH protocol permits 1-2 drops to each affected eye for adult patients. In the pediatric patient, limit the dose to just one drop in the affected eye(s). Tetracaine should not be used if the patient has suffered a penetrating injury to the eye or has an existing allergy to any of the “-caine” family of medications (i.e., novocaine, lidocaine, etc.).
Following the administration of tetracaine drops, the patient may complain of a burning sensation, sensitivity to light, tearing, or redness of the eye. It is imperative to keep the patient from rubbing or scratching at the eye and to continue to protect the eye from injury while it is still numb. Per UH protocols, any patient receiving tetracaine drops is required to be transported for further evaluation.
When administering medication to the eye, the medic should wear gloves. Remove contact lenses from the patient’s eyes if they are wearing them. Have the patient lie flat if possible or tilt their head back. The medic should apply light pressure just below the lower eyelid on the cheekbone with their finger or thumb and pull down to expose the conjunctival sac. Remember, the patient will often want to close or rub the injured eye, so one will need to physically open the eyelid and keep the patient from rubbing or scratching at the eye. Without touching the eye with your finger or the dropper, place the drop on the conjunctival sac and have the patient close their eye after administration.
