Eye drops, while intended for the eyes, can sometimes lead to an upset stomach. The components of eye drops can enter the digestive system and cause discomfort.
How Eye Drops Reach the Digestive System
After eye drops are applied, they mix with the tear film covering the eye’s surface. Excess fluid and dissolved medication drain through small openings in the inner corner of the eyelids, known as the puncta. These puncta lead into tiny canals called canaliculi, which merge to form the common canaliculus.
This common canaliculus empties into the nasolacrimal duct, which extends into the nasal cavity. From the nasal cavity, liquid drains into the back of the throat. Once swallowed, it enters the stomach, where it can be absorbed or directly irritate the gastrointestinal lining.
Ingredients That May Cause Digestive Discomfort
Certain active ingredients in eye drops can affect the digestive system if swallowed and absorbed systemically. For instance, beta-blockers like timolol, commonly used for glaucoma, can lower heart rate and blood pressure throughout the body. Ingested, these medications may slow gastrointestinal motility, leading to nausea, abdominal cramps, or indigestion.
Anticholinergic medications, such as atropine (used for pupil dilation), can also affect the gut. These drugs block the action of acetylcholine, a neurotransmitter involved in controlling muscle contractions and secretions in the digestive tract. This interference can result in slowed bowel movements and constipation, contributing to abdominal discomfort.
Antihistamine or decongestant eye drops, used for allergy or redness relief, can also induce digestive upset if absorbed systemically. Antihistamines can cause drowsiness and nausea, while decongestants may lead to jitters or stomach unease. Preservatives, such as benzalkonium chloride (BAK), found in many multi-dose eye drop solutions, can also contribute to irritation. While primarily active on the eye’s surface, if swallowed in sufficient quantities, BAK can cause direct irritation to the sensitive lining of the gastrointestinal tract, potentially leading to mild nausea or stomach upset.
Recognizing and Managing Symptoms
Digestive symptoms from eye drops can vary and typically involve mild to moderate discomfort, including nausea, abdominal cramping, indigestion, or mild diarrhea. These symptoms usually appear shortly after drop application and tend to resolve as the medication is processed by the body.
To minimize the likelihood of eye drops reaching the digestive system, proper administration techniques are recommended. After placing a drop in the eye, gently close your eyelid and press a finger against the inner corner of your eye, near the nose, for one to two minutes. This technique, known as nasolacrimal occlusion, helps block the tear drainage system, reducing systemic absorption.
Ensuring you use only the prescribed number of drops and avoiding excessive blinking immediately after application can also help. If digestive symptoms occur, especially if they are severe or persistent, it is advisable to stop using the drops temporarily and consult a healthcare professional. Staying hydrated may help alleviate mild discomfort, but severe pain, persistent vomiting, or dehydration warrant immediate medical attention.