When used, “only as directed,” tetrahydrozoline is an effective medication which shrinks blood vessels thus alleviating reddened “bloodshot” eyes. If taken internally, however, this drug acts like a potent high blood pressure medicine.
Symptoms reported in both children and adults who have swallowed some of these eye care products either by accident or via malicious activity include marked drowsiness, low blood pressure, slowed heart rate, and possibly even coma and impaired breathing.
Quantities as low as ½ to 1½ teaspoonfuls (approximately 1/6 to ½ of a half ounce bottle) have caused pronounced reactions in small children. Toxic affects following tetrahydrozoline ingestion can be serious and at times require close observation and treatment in an intensive care setting. Fortunately, no deaths have been reported.
It is important to point out that tetrahydrozoline is the active ingredient not only in Visine®, but also found in a variety of brand name products including Murine®, Opti-Clear®, Altazine®, Optigene 3®, Redness Reliever® and other generic products. Other drugs which are similar to tetrahydrozoline used in eye drops and nasal decongestants include xylometazoline, oxymetazoline and naphazoline.
When used and stored properly, tetrahydrozoline eye drops are safe and effective. But everyone should be mindful of the potential for toxicity from accidental poisoning in children or malicious misuse by adolescents and adults. Additionally, parents and caregivers of small children should be encouraged to keep these products (usually not in child resistant packaging) out-of-reach as they would safely store other prescription and over-the-counter medications.
Anyone who becomes aware of a known or suspected tetrahydrozoline eye drop ingestion, regardless if intentional or unintentional in nature, should immediately consult the Illinois Poison Center by calling 1-800-222-1222.