Tetracaine Side Effects: What to Expect and When to Call Your Doctor

Tetracaine is a fast-acting local anesthetic used to numb the eye, skin, or spinal region before medical procedures. Like all medications, it can cause side effects — though for most patients, those are minor, brief, and limited to the site of application. This guide covers what to expect, what's normal, and when to seek medical attention.

Common Side Effects of Tetracaine Eye Drops

The most common side effects of tetracaine ophthalmic 0.5% drops occur at the site of instillation and are temporary:

Transient stinging or burning: Most patients experience a brief stinging sensation immediately after the drop is instilled. This typically resolves within 1–2 minutes.

Conjunctival redness: The white of the eye may appear red for a few minutes. This is a normal response and clears as the medication works.

Temporary eye numbness: This is the intended effect. The anesthetic numbs the cornea and conjunctiva so procedures can be performed comfortably. Effects last approximately 10–15 minutes after a single drop.

Watering eyes (lacrimation): Minor tearing is common immediately after instillation.

Eye irritation or discomfort: Mild discomfort or itching at the eye surface may occur briefly.

Studies show that tetracaine eye drops cause more stinging upon instillation than proparacaine drops, though the anesthetic effect is comparable. Your eye doctor is aware of this and may choose proparacaine if you have a history of sensitivity.

Important: Don't Touch or Rub Your Eye

After receiving tetracaine eye drops, your eye will be numb for up to 20 minutes. During this time, you won't feel pain signals normally — which means you could accidentally injure the eye without realizing it. Avoid touching, rubbing, or poking at the eye until sensation fully returns.

Serious Side Effects of Tetracaine

While serious reactions are rare, they do occur. Seek immediate medical attention if you experience:

Allergic reaction: Hives, swelling of the face, lips, or throat, or difficulty breathing. Allergic reactions to tetracaine are rare but possible, particularly after repeated use over months or years. The PABA metabolite of ester anesthetics is the usual culprit.

Methemoglobinemia: A rare but serious blood disorder where hemoglobin can no longer carry oxygen effectively. Risk increases when tetracaine is combined with other oxidizing agents (e.g., nitroglycerin, dapsone). Symptoms include bluish skin/lips, headache, rapid heartbeat, confusion, and fatigue. Requires emergency treatment with methylene blue.

Systemic toxicity (with overdose or excessive absorption): Occurs if too much tetracaine is absorbed — most likely with topical preparations applied over large skin areas or under occlusive dressings. Symptoms include dizziness, confusion, tremors, slow or irregular heartbeat, or seizures.

Corneal damage (long-term use): Long-term use of tetracaine eye drops can cause irreversible corneal damage and vision loss. This is why tetracaine is only administered by healthcare providers during specific procedures — not prescribed for ongoing home use.

Hypotension (spinal tetracaine): When tetracaine is used for spinal anesthesia, sympathetic blockade can cause peripheral vasodilation and blood pressure drop. This is monitored closely by anesthesia staff in the operating room.

Side Effects of Tetracaine Topical Solution (Skin Use)

When tetracaine 2% is applied to the skin, side effects are generally local and mild. Seek immediate care if you experience severe burning, swelling, or persistent irritation at the treated site, or any signs of systemic absorption (dizziness, confusion, irregular heartbeat).

Always apply the smallest amount needed, avoid applying over large areas, and never apply under occlusive wraps without medical guidance.

When to Call Your Doctor

Contact your provider if you notice:

Redness, swelling, or discharge from the eye that persists more than a few hours after a procedure

Vision changes after receiving tetracaine eye drops

Skin reaction that worsens, spreads, or does not improve within 7 days (topical use)

Any symptoms of systemic reaction (racing heart, confusion, bluish tint to skin)

For more on drug interactions that can worsen tetracaine side effects, see: Tetracaine Drug Interactions: What to Avoid and What to Tell Your Doctor.

For a complete medication overview, see: What Is Tetracaine? Uses, Dosage, and What You Need to Know.