Pharmacology Update

Lidocaine Powder Intradermal Injection System (Zingo™)

By William T. Elliott, MD, FACP, and James Chan, PharmD, PhD. Dr. Elliott is Chair, Formulary Committee, Northern California Kaiser Permanente; Assistant Clinical Professor of Medicine, University of California, San Francisco; Dr. Chan is Pharmacy Quality and Outcomes Manager, Kaiser Permanente, Oakland, CA. Drs. Chan and Elliott report no financial relationship to this field of study.

The FDA has approved a product for topical anesthesia prior to venous access procedures such as venipuncture or peripheral intravenous cannulations in children. The device is a needle-free single-use helium-powered intradermal delivery system containing 0.5 mg of lidocaine hydrochloride monohydrate. It is marketed by Anesiva as Zingo.

Indications

Lidocaine intradermal injection system is approved to provide local analgesia prior to venous access procedures in children ages 3 to 18 years of age.1

Dosage

One dose from the intradermal delivery system is delivered one to three minutes prior to needle insertion. The procedure should be completed within 10 minutes after administration.1

Potential Advantages

The system provides a needle-free delivery dose of local anesthetic with effect observed if given one to three minutes prior to venous access.1 Typically topical anesthetics such as lidocaine/prilocaine emulsion (EMLA ), lidocaine liposomal cream (ELA-Max ) lidocaine/tetracaine patch (Synera ) requires administration 20 to 60 minutes prior to the procedure.2,3,4

Potential Disadvantages

Adverse events are local in nature. The most frequent are erythema (53% vs 27% for placebo), petechiae (44% vs 5%), and edema (5% vs 3%).1

Comments

This is a novel delivery system for lidocaine. Efficacy was shown in 2 randomized, double-blind, parallel-arm, sham placebo controlled trials (n = 1,109).1 The system reduced pain, compared to placebo, when administered one to three minutes prior to venous access. Administrations were to the back of the hand or the antecubital fossa. Pain was assessed using a 6-point categorical scale using faces to reflect the degree of pain ranging from 'no hurt' to 'hurt worst.' The adjusted means difference between groups was statistically significant, but modest (-0.33 to -0.39), representing a 16% to 22% reduction compared to placebo. The upper limit of the 95% confidence interval ranged from -0.58 to -0.65 or about 2/3rd of a point on a 6 point scale. Currently there are no comparative studies between the lidocaine intradermal system with other topical anesthetics such as EMLA, ELA-Max, Synera or administration of lidocaine using a needle-free device such as J-Tip. The administration of 0.25 ml of a buffered 1% lidocaine solution using this device one to three minutes before insertion has been shown to be significantly more effective than EMLA (mean of 69 minutes) in reducing pain associated with intravenous catheter insertion.5 The cost of Zingo was not available at the time of this review. The cost has been estimated to be $12 to $16 per injection.6

Clinical Implications

Needle insertion is regarded as a frightening and bothersome procedure for children.7 There has been an increase in the reported use of topical or local anesthetics for venipuncture.8 The slow onset of existing products is problematic in certain practice settings such as the emergency room. The onset of action of Zingo is certainly an attractive feature. However, it is not clear how effective the analgesic effect really is without an active control.

References

1. Zingo Product Information. Anesiva, Inc. August 2007.

2. Synera Product Information. Ferndale Laboratory, Inc. June 2005.

3. Kleiber C, et al. Pediatrics. 2002;110:758-761.

4. Eichenfield LF et al. Pediatrics. 2002;109:1093-1099.

5. Jimenez N, et al. Anesth Analg. 2006;102:411-414.

6. http://seekingalpha.com/article/44956-zingo-approval-makes-anesiva-an-appealing-takeover-target-for-endo-pharma. Accessed 9/20/07.

7. Cummings EA. Pain. 1996;68:25-31.

8. Khan AH, Sachdeva S. Clin Pediatr. (Phila) 2007;46 (7):626-631.