Before using Emla Patch, tell your healthcare provider about any medical conditions, allergies, or medications you are taking.
Emla Patch is a topical anesthetic used to temporarily numb the skin before certain medical procedures, such as blood tests, vaccinations, injections, and intravenous (IV) catheter insertion.
Although Emla Patch is generally well tolerated when used correctly, it may cause side effects in some people. The risk of serious reactions may increase when too many patches are used, the patch is left on longer than recommended, or the medication is applied to damaged skin.
Certain medical conditions, including blood disorders, liver disease, and kidney disease, may also require additional precautions.
Always follow the recommended application instructions and treatment duration to help reduce the risk of unwanted side effects.
Allergic Reactions and Hypersensitivity
Do not use Emla Patch if you are allergic to lidocaine, prilocaine, other similar local anesthetics, or any of the ingredients in the patch.
Lidocaine and prilocaine belong to a class of medications called amide-type local anesthetics. These medications work by temporarily blocking nerve signals in the treated area, reducing pain and sensitivity.
Although allergic reactions to these medications are uncommon, they can occur in some people.
Tell your healthcare provider if you have a history of allergies, particularly if you have previously experienced an allergic reaction to a local anesthetic used during dental treatments, injections, or minor medical procedures.
Possible symptoms of an allergic reaction include:
- Skin Rash: You may develop redness, hives, or an unusual rash.
- Itching: The treated area or other parts of your body may become itchy.
- Swelling: You may notice swelling around the application site, face, or lips.
- Skin Irritation: Burning, redness, or discomfort may become more severe after applying the patch.
- Breathing Difficulties: A severe allergic reaction may cause wheezing, shortness of breath, or throat swelling.
Stop using Emla Patch and contact your healthcare provider if you develop a new rash, unusual swelling, or persistent irritation.
Seek emergency medical attention immediately if you experience difficulty breathing or swelling of your face, tongue, lips, or throat.
Application to Damaged or Irritated Skin
Emla Patch is designed for use on healthy, intact skin.
Do not apply the patch to open wounds, cuts, scrapes, burns, rashes, or other areas where the skin is damaged.
Broken or inflamed skin may absorb lidocaine and prilocaine more quickly than healthy skin. This can increase the amount of medication entering your bloodstream and raise your risk of side effects.
Tell your healthcare provider if you have eczema, atopic dermatitis, psoriasis, or another skin condition affecting the area where you plan to apply the patch.
Some inflammatory skin conditions may change how quickly the medication is absorbed, which can affect the appropriate application time.
Emla Patch should not be applied to mucous membranes, including the inside of your mouth or nose.
If the skin at your intended application site is irritated, infected, or damaged, ask your healthcare provider whether another location or anesthetic treatment would be more appropriate.
Use in Infants and Children
Emla Patch should be used with particular caution in infants and young children because they may be more sensitive to the effects of lidocaine and prilocaine.
One of the most important concerns is methemoglobinemia, a rare but potentially serious blood condition that reduces the blood’s ability to carry oxygen effectively.
Infants younger than three months are at greater risk because their bodies are less able to process certain substances that can cause methemoglobinemia.
According to Canadian product information, Emla Patch should not be used in infants younger than three months unless a healthcare professional specifically recommends it. When prescribed for this age group, strict limits apply to the number of patches and application duration.
For older infants and children, the recommended number of patches and maximum application time depend on age, body weight, and medical condition.
Children should be monitored carefully during and after treatment, especially if they have other risk factors for methemoglobinemia.
Possible warning signs include unusual tiredness, weakness, difficulty breathing, or blue, grey, or brownish discolouration of the lips, skin, or fingernails.
If your child develops any of these symptoms, remove the patch and seek emergency medical attention.
Never apply more patches or leave them on longer than recommended by your child’s healthcare provider.
Methemoglobinemia Risk
Emla Patch contains prilocaine, a local anesthetic that can occasionally cause methemoglobinemia.
Methemoglobinemia occurs when an excessive amount of hemoglobin in the blood changes into a form that cannot carry oxygen effectively.
As a result, your body’s tissues and organs may not receive enough oxygen.
Although this condition is rare, it can become life-threatening if not treated promptly.
The risk may be higher in infants, people with glucose-6-phosphate dehydrogenase (G6PD) deficiency, individuals with certain blood disorders, and those taking medications that increase methemoglobin formation.
Possible symptoms include:
- Blue or Grey Skin Discoloration: Your lips, fingernails, or skin may appear bluish, greyish, or brownish.
- Difficulty Breathing: You may experience shortness of breath or unusually rapid breathing.
- Severe Tiredness: You may feel extremely weak or exhausted.
- Dizziness or Headache: You may become lightheaded or experience a persistent headache.
- Confusion: Severe cases may cause unusual confusion or reduced alertness.
- Rapid Heartbeat: Your heart may beat faster as your body attempts to compensate for reduced oxygen delivery.
Symptoms may develop during or after use.
Remove Emla Patch and seek emergency medical attention immediately if you notice signs of methemoglobinemia.
Tell your healthcare provider if you or your child have G6PD deficiency, a history of methemoglobinemia, or another condition affecting how the blood carries oxygen.
Drug Interactions and Concurrent Medications
Before using Emla Patch, tell your healthcare provider or pharmacist about all medications and supplements you take.
Certain medications may increase the risk of methemoglobinemia when used with prilocaine.
These include some antibiotics and other medications that can affect the blood’s ability to carry oxygen.
Examples include sulfonamide antibiotics, dapsone, and certain other medications associated with methemoglobin formation.
Using Emla Patch with other local anesthetics may also increase your overall exposure to lidocaine or similar medications.
This could increase the risk of side effects affecting your nervous system or heart.
Certain medications used to treat irregular heart rhythms, such as amiodarone or mexiletine, may also require additional precautions.
Tell your healthcare provider if you use prescription medications, over-the-counter products, topical anesthetic creams, herbal supplements, or other products containing lidocaine or prilocaine.
Do not combine Emla Patch with other numbing medications unless your healthcare provider confirms that they can be used safely together.
Systemic Absorption and Overuse
Although Emla Patch is applied directly to your skin, small amounts of lidocaine and prilocaine can enter your bloodstream.
When the patch is used correctly, the amount absorbed is generally limited. However, using too many patches, leaving them on longer than recommended, or applying them to damaged skin may increase absorption.
Excessive exposure to local anesthetics can cause serious side effects involving the nervous system, heart, or blood.
Possible warning signs include dizziness, unusual drowsiness, ringing in the ears, confusion, tremors, or seizures.
In severe cases, excessive local anesthetic absorption may cause dangerous changes in heart rhythm or other life-threatening complications.
The risk may be greater in people with severe liver disease, kidney disease, certain heart conditions, or other medical conditions that affect how the body processes medications.
Your healthcare provider may recommend a different number of patches or a shorter application time based on your medical history.
Do not use more patches or leave Emla Patch on your skin longer than instructed. Applying additional medication will not necessarily improve pain relief and may increase the risk of serious complications.
Choking and Accidental Swallowing
Emla Patch can present a choking or poisoning hazard if it becomes detached and is placed in a child’s mouth.
Infants and young children may try to remove the patch, chew it, or swallow it.
Because the patch contains lidocaine and prilocaine, accidental swallowing can expose a child to potentially harmful amounts of local anesthetic.
If you are applying Emla Patch to a child, make sure the patch is securely attached and cannot easily be removed.
Supervise your child during treatment, particularly if they frequently put their fingers or objects into their mouth.
Take extra care with infants who are lying on their stomachs or in positions where the patch may become loose or difficult to monitor.
Avoid placing the patch where a child can easily reach it or pull it off.
After use, fold the patch in half with the adhesive sides together and dispose of it safely.
If a child chews or swallows an Emla Patch, seek immediate medical advice or contact a poison control center. Do not wait for symptoms to develop.
Eye Contact and Eye Irritation
Emla Patch should not come into contact with your eyes.
Lidocaine and prilocaine temporarily reduce sensation in the areas where they are applied. If the medication enters your eye, it may cause irritation and temporarily reduce your eye’s ability to detect discomfort.
This can increase the risk of corneal injury because you may not immediately notice irritation, scratching, or foreign particles.
If Emla medication accidentally gets into your eye, rinse it thoroughly with clean water or saline.
Avoid rubbing your eye and protect it from further irritation until normal sensation returns.
Contact your healthcare provider promptly if you experience persistent redness, pain, blurred vision, or sensitivity to light.
Do not apply Emla Patch around your eyes unless a healthcare professional has specifically instructed you to use an appropriate anesthetic preparation for that area.
Skin Irritation and Local Reactions
Some people may experience mild skin reactions after applying Emla Patch.
These reactions usually occur at the application site and may include redness, temporary whitening of the skin, mild swelling, itching, or a burning sensation.
The skin may also feel unusually warm or sensitive after the patch is removed.
In most cases, these effects are temporary and disappear as the medication wears off.
However, persistent redness, severe itching, blistering, or increasing swelling may indicate irritation or an allergic reaction.
If you experience severe or worsening skin symptoms, remove the patch and contact your healthcare provider.
Avoid scratching or rubbing the treated area, especially while your skin remains numb.
Because Emla Patch temporarily reduces pain sensation, you may not notice minor injuries or irritation immediately.
Protect the treated skin from excessive heat, cold, scratching, and pressure until normal sensation returns.
Pregnancy and Breastfeeding
If you are pregnant, planning to become pregnant, or breastfeeding, speak with your healthcare provider before using Emla Patch.
Lidocaine and prilocaine may enter your bloodstream after being absorbed through the skin. The amount absorbed depends on the number of patches used, how long they remain in place, and the condition of your skin.
Available information has not established a clear risk of birth defects from appropriate use, but data specifically evaluating Emla Patch during pregnancy are limited.
Your healthcare provider will consider whether the expected benefits of temporary skin anesthesia outweigh any potential risks.
If you are breastfeeding, small amounts of lidocaine and prilocaine may pass into breast milk after systemic absorption. However, exposure to a breastfed infant is expected to be low when the patch is used appropriately.
Your healthcare provider can determine whether Emla Patch is suitable for you while breastfeeding.
Avoid applying the patch directly to your breasts or nipples unless specifically instructed by a healthcare professional.
Do not use additional patches or extend the recommended application time without medical advice.
When to Contact Your Healthcare Provider
Contact your healthcare provider if you develop persistent skin redness, swelling, burning, itching, or other unexpected symptoms after using Emla Patch.
You should also seek medical advice if you have an existing skin condition, a history of allergic reactions to local anesthetics, or concerns about using the patch on a child.
Seek emergency medical attention immediately if you experience difficulty breathing, seizures, severe confusion, an irregular heartbeat, or blue, grey, or brownish skin discolouration. These symptoms may indicate a serious reaction requiring urgent treatment.
Always follow the recommended number of patches, application time, and instructions for the treatment area.
Emla Patch can help reduce pain during minor medical procedures, but correct application is essential for safe and effective use. Following the recommended precautions can help minimize skin irritation, excessive anesthetic absorption, and other potentially serious side effects.
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