SYNERA- lidocaine and tetracaine patch
Galen US Incorporated


SYNERA is a combination amide and ester local anesthetic indicated for use on intact skin to provide local dermal analgesia for superficial venous access and superficial dermatological procedures such as excision, electrodessication and shave biopsy of skin lesions [see Clinical Studies ( 14)] .


SYNERA should only be applied to intact skin. Use immediately after opening the pouch.

For adults and children 3 years of age and older:

  • Venipuncture or Intravenous Cannulation: Prior to venipuncture or intravenous cannulation, apply SYNERA to intact skin for 20 to 30 minutes.
  • Superficial Dermatological Procedures: For superficial dermatological procedures such as superficial excision or shave biopsy, apply SYNERA to intact skin for 30 minutes prior to the procedure.

While efficacy has not been established for children less than 3 years of age, safe use of SYNERA in infants 4 to 6 months of age was documented in one study.

Simultaneous or sequential application of multiple SYNERA patches is not recommended. However, application of one additional patch at a new location to facilitate venous access is acceptable after a failed attempt. When SYNERA is used concomitantly with other products containing local anesthetic agents, the amount absorbed from all formulations should be considered, as local anesthetics are thought to have at least additive toxicities. If irritation or a burning sensation occurs during application, remove the patch.


SYNERA topical patch contains 70 mg lidocaine and 70 mg tetracaine, has a total skin contact area of 50 cm 2 , and an active drug-containing area of 10 cm 2.


  • SYNERA is contraindicated in patients with a known history of sensitivity to lidocaine, tetracaine, or local anesthetics of the amide or ester type.
  • SYNERA is also contraindicated in patients with para-aminobenzoic acid (PABA) hypersensitivity and in patients with a known history of sensitivity to any other component of the product.


5.1 Methemoglobinemia

Cases of methemoglobinemia have been reported in association with local anesthetic use. Although all patients are at risk for methemoglobinemia, patients with glucose-6-phosphate dehydrogenase deficiency, congenital or idiopathic methemoglobinemia, cardiac or pulmonary compromise, infants under 6 months of age, and concurrent exposure to oxidizing agents or their metabolites are more susceptible to developing clinical manifestations of the condition. If local anesthetics must be used in these patients, close monitoring for symptoms and signs of methemoglobinemia is recommended.

Signs of methemoglobinemia may occur immediately or may be delayed some hours after exposure, and are characterized by a cyanotic skin discoloration and/or abnormal coloration of the blood. Methemoglobin levels may continue to rise; therefore, immediate treatment is required to avert more serious central nervous system and cardiovascular adverse effects, including seizures, coma, arrhythmias, and death. Discontinue SYNERA and any other oxidizing agents. Depending on the severity of the signs and symptoms, patients may respond to supportive care, i.e., oxygen therapy, hydration. A more severe clinical presentation may require treatment with methylene blue, exchange transfusion, or hyperbaric oxygen.

5.2 Overexposure

Application of a SYNERA patch for longer duration than recommended, or the simultaneous or sequential application of multiple SYNERA patches, could result in sufficient absorption of lidocaine and tetracaine to result in serious adverse effects [see Overdosage ( 10)] .

5.3 Storage and Disposal

Used SYNERA patches contain a large amount of lidocaine and tetracaine (at least 90% of the initial amount). The potential exists for a child or pet to suffer serious adverse effects from chewing or ingesting a new or used SYNERA patch. It is important for patients to store and dispose of SYNERA out of the reach of children and pets.

5.4 Avoidance of Exposure to Eyes and Mucous Membranes

  • Contact of SYNERA with the eyes should be avoided based on the findings of severe eye irritation with the use of similar products in animals. Also, the loss of protective reflexes may predispose to corneal irritation and potential abrasion. If eye contact occurs, immediately wash out the eye with water or saline and protect the eye until sensation returns.
  • SYNERA is not recommended for use on mucous membranes or on areas with a compromised skin barrier because these uses have not been studied. Application to broken or inflamed skin may result in toxic blood concentrations of lidocaine and tetracaine from increased absorption.

5.5 Magnetic Resonance Imaging

The integrated heating component contains iron powder; therefore, the SYNERA patch must be removed before a patient undergoes magnetic resonance imaging.

5.6 Allergic Reactions

Allergic or anaphylactoid reactions associated with lidocaine, tetracaine, or other components of SYNERA can occur. They are characterized by urticaria, angioedema, bronchospasm, and shock. If an allergic reaction occurs, it should be managed by conventional means.

5.7 Special Patient Populations

  • SYNERA should be used with caution in patients who may be more sensitive to the systemic effects of lidocaine and tetracaine particularly the acutely ill or debilitated.
  • Patients with severe hepatic disease or pseudocholinesterase deficiency, because of their inability to metabolize local anesthetics normally, are at a greater risk of developing toxic plasma concentrations of lidocaine and tetracaine.

5.8 Vaccinations

Lidocaine has been shown to inhibit viral and bacterial growth. The effect of SYNERA on intradermal injections of live vaccines has not been determined.


6.1 Clinical Studies Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

Three different formulations were studied during clinical development of SYNERA: Developmental A (n=138), Developmental B (n=30), and the SYNERA final formulation (n=1281). The developmental patch formulations each contained the same amount of the active drug (70 mg each of lidocaine and tetracaine) as the final patch formulation, but varying amounts of excipients, principally polyvinyl alcohol and water. Data obtained from studies utilizing the developmental patches have been included in the overall evaluation of SYNERA safety (calculation of adverse event incidence).

Most common adverse events in clinical trials

Localized Reactions

During or immediately after treatment with SYNERA, the skin at the site of treatment may develop erythema, blanching, edema, or abnormal sensation. In clinical studies involving 1449 SYNERA-treated subjects, the most common local reactions were erythema (71%), blanching (12%) and edema (12%). These reactions were generally mild, resolving spontaneously soon after patch removal. There were no treatment-related serious adverse events.

Other application site reactions of various types (contact dermatitis, rash, skin discoloration) occurred in less than 4% of SYNERA-treated patients during clinical trials. Of these adverse events, 75% were mild, resolving spontaneously soon after patch removal.

Application site-related adverse events that occurred in 1% or less of SYNERA-treated subjects included rash, pruritus, pain, contact dermatitis, infection, skin discoloration, allergic reaction, blister, paresthesia, urticaria, and vesiculobullous rash.

Allergic Reactions

Allergic or anaphylactoid reactions can occur with the active or inactive components of SYNERA. They may be characterized by urticaria, angioedema, bronchospasm, and shock. Allergic reactions to the patch should be managed by conventional means.

Systemic (Dose-Related) Reactions

Systemic adverse reactions that occurred in 1% or less of SYNERA-treated subjects included dizziness, headache, nausea, somnolence, and vomiting. Systemic adverse effects of lidocaine and tetracaine are similar in nature to those observed with other amide and ester local anesthetic agents, including CNS excitation and/or depression (light-headedness, nervousness, apprehension, euphoria, confusion, dizziness, drowsiness, tinnitus, blurred or double vision, vomiting, sensations of heat, cold or numbness, twitching, tremors, convulsions, unconsciousness, respiratory depression and arrest). Excitatory CNS reactions may be brief or not occur at all, in which case the first manifestation may be drowsiness merging into unconsciousness. Signs of CNS toxicity may start at plasma concentrations of lidocaine as low as 1000 ng/mL. The plasma concentrations at which tetracaine toxicity may occur are less well characterized; however, systemic toxicity with tetracaine is thought to occur with much lower plasma concentrations compared with lidocaine. The toxicity of co-administered local anesthetics is thought to be at least additive. Cardiovascular manifestations may include bradycardia, hypotension and cardiovascular collapse leading to arrest.

All resources are included in as near-original form as possible, meaning that the information from the original provider has been rendered here with only typographical or stylistic modifications and not with any substantive alterations of content, meaning or intent.

This site is provided for educational and informational purposes only, in accordance with our Terms of Use, and is not intended as a substitute for the advice of a medical doctor, nurse, nurse practitioner or other qualified health professional.

Privacy Policy | Copyright © 2021. All Rights Reserved.