"Our understanding is that the pain associated with superficial venous access is not treated in a consistent manner," Campbell said. "This evidence indicates that the patch takes effect anywhere from 20 to 30 minutes after application."

The lidocaine/tetracaine patch was approved by the U.S. Food and Drug Administration to provide analgesia during superficial venous access and superficial dermatological procedures.

In the first study, patients aged seven to 18 were randomised to receive either the lidocaine/tetracaine patch formulation, which contains a mixture of 70 mg of lidocaine and 70 mg of tetracaine, or to receive a heated placebo patch, both over the antecubital vein. The active patch or placebo was applied for 30 minutes.

In the second study, patients aged seven to 17 were randomised to use either the lidocaine/tetracaine patch or placebo for 20 minutes.

Patients were excluded from the study if they had allergies or sensitivities to lidocaine, tetracaine or other local anaesthetics. They were also excluded if they had damaged, denuded, or broken skin at the treatment site.

After the patches were administered and the vascular access procedures were performed, patients rated their pain on the OUCHER!^(TM) scale, where 0 indicated no pain and 100 indicated worst pain.

In both studies, the patients in the active treatment group rated their pain as 0 whereas the median pain scores for placebo patients were 35 in the first study and 20 in the second study, with P <.001 in both studies.

Evaluations by a study investigator were consistent with the patient's pain ratings in both studies (P <.001), and evaluations by an independent observer were consistent with the patient's pain ratings in the second study (P <.001), but slightly different than in the first study (P <.05).

"The results from the children were corroborated by the investigator and an independent observer," Campbell said in an interview.

Adverse events that occurred were mild, he said. Erythema was significantly more common with the lidocaine/tetracaine patch than placebo in both studies (25 vs 8 and 27 vs 13, P <.001, respectively).

There were four cases of oedema in the second study amongst lidocaine/tetracaine patch patients and no cases amongst patients who got placebo. There was a statistically significant difference in oedema incidence in the first study (9 vs 3 cases, P =.033).

The study was conducted and sponsored by ZARS Pharma and supported by Endo Pharmaceuticals.


[Presentation title: A Lidocaine/Tetracaine Patch for Local Anesthesia Prior to Vascular Access Procedures in Children: Results from Two Randomized Controlled Studies. Abstract 7900.27]

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