Outgro Pain Relief Side Effects: What to Expect and When to Call Your Doctor

Outgro Pain Relief contains benzocaine 20% — a topical local anesthetic that temporarily numbs the skin. For most people, the product is well tolerated when used as directed. But benzocaine is not without risks. The FDA has issued multiple safety communications about benzocaine products over the years, and there are specific side effects and warning signs you need to know before using Outgro.

Common Side Effects of Outgro Pain Relief

The most common side effects of Outgro Pain Relief (benzocaine 20% topical) are localized to the area of application and are usually mild and temporary:

Temporary stinging or burning — Brief discomfort at the application site, especially on broken or irritated skin. This typically fades within 1-2 minutes.

Redness at the application site — Mild skin redness that usually resolves quickly.

Skin irritation — Some users experience localized irritation or sensitivity.

These common effects are expected and generally not a reason to stop use. However, if stinging or redness is severe, or if the skin reaction worsens rather than improves, discontinue use and contact your doctor.

Serious Side Effect: Methemoglobinemia

The most serious risk associated with benzocaine is methemoglobinemia — a rare but potentially life-threatening blood disorder. The FDA has received reports of more than 400 cases of benzocaine-associated methemoglobinemia since 1971.

Methemoglobinemia occurs when benzocaine converts normal hemoglobin into methemoglobin — a form that cannot carry oxygen effectively. This reduces the oxygen available to your body's tissues and can become dangerous or fatal if not treated.

Symptoms of methemoglobinemia (seek emergency care immediately):

Pale, gray, or blue-colored skin, lips, or nail beds

Shortness of breath

Confusion or altered mental status

Fatigue or unusual tiredness

Rapid heart rate

Headache or lightheadedness

Symptoms typically appear within minutes to 2 hours after application and can occur even after prior uses without issue. If you experience any of these symptoms, stop using the product and call 911 or get emergency medical help immediately.

Who Is at Higher Risk for Benzocaine Side Effects?

Some people are at higher risk for methemoglobinemia from benzocaine:

People with breathing disorders: asthma, bronchitis, emphysema, or COPD

People with heart disease

The elderly

Infants younger than 4 months (higher risk; product is not for use in children under 2)

People with G6PD deficiency or pyruvate kinase deficiency

People with a personal or family history of methemoglobinemia

Smokers

Allergic Reactions to Outgro Pain Relief

Benzocaine can cause allergic reactions in some people. Stop using the product and seek medical help right away if you experience:

Hives or skin rash beyond the application site

Swelling of the face, lips, or throat

Difficulty breathing

Tingling in the mouth or throat

Additional Safety Warnings for Outgro

Extremely flammable: Outgro contains alcohol. Do not use near fire, flame, or while smoking. Allow the product to dry fully before exposure to heat.

Eye contact: Avoid getting the product in your eyes. If it does, flush with water for 15 minutes.

7-day rule: If the condition doesn't improve within 7 days, or improves then comes back, stop use and see a doctor.

Overdose warning: Using benzocaine on large areas of skin or using more than recommended increases absorption and risk of serious side effects including seizure, uneven heartbeat, or respiratory failure in overdose situations.

For information on drug interactions that can increase the risk of side effects, see: Outgro Pain Relief Drug Interactions: What to Avoid and What to Tell Your Doctor

If you're concerned about benzocaine side effects and want a safer alternative, see: Alternatives to Outgro Pain Relief