• 
• 

Three Part Question

In [children with minor skin lacerations requiring suturing], is [lignocaine, epinephrine, tetracaine gel more effective than tetracaine, epinephrine, cocaine gel] as a [topical anaesthetic agent]

Clinical Scenario

A 9-year-old boy presents with a 3 cm laceration to his left knee after falling off his bike. The wound requires closure by suturing but the patient tells you he is scared of needles. You explain that you can numb the area first using a special anaesthetic gel. You have lignocaine, epinephrine, tetracaine gel available in the department but your consultant has told you of another form of topical anaesthetic that she has used in the past containing tetracaine, epinephrine and cocaine. You wonder which topical anaesthetic is most effective.

Search Strategy

Ovid MEDLINE® 1948 to December Week 1 2011
EMBASE® 1980 to present (Dec 2011)
Cochrane Database
([lidocaine.mp. or exp Lidocaine] OR [lignocaine.mp.]) AND ([tetracaine.mp. or exp Tetracaine] OR [amethocaine.mp.]) AND [adrenaline.mp. or exp Epinephrine] AND [cocaine.mp. or exp Cocaine] AND ([wound.mp. or exp "Wounds and Injuries"] OR [laceration.mp. or exp Lacerations])



The references of review articles were also searched for articles relevant to the three-part question

Search Outcome

The MEDLINE search produced 26 papers, of which 3 were relevant to the three-part question.

The EMBASE search produced 6 papers of which none was relevant to the three part-question.

The Cochrane database contained one review which was relevant to the three-part question but was the same study highlighted from the MEDLINE search.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Ernst et al, 1995, USA	A total of 95 patients aged 5 to 17 were included in the statistical analysis with 47 receiving TAC gel and 48 receiving LAT gel.	Randomized, prospective, double-blinded clinical trial - Level 1b	Analgesic efficacy	No statistically significant difference was detected between the LAT versus TAC groups (P=.80). For patient ranked sum ratings of TAC and LAT no statistically significant differences were detected in pain scores (P=.71).	Small sample sizes. No power calculation performed. Blood levels were not measured to substantiate absorption.
			Quantity	The mean amount of gel used in both the TAC and the LAT groups was 1.5cc corresponding to 177mg of cocaine for TAC and 60mg of lidocaine for LAT.
			Cost	The gel form of LAT is considerably less expensive than TAC gel ($3.00 for LAT compared to $35.00 for TAC).
Schilling et al, 1995, USA	One hundred and seventy one children (151 after exclusions/withdrawals) were randomised to receive either TAC or LET solutions.	Randomized, prospective, double-blinded clinical trial - Level 1b	Adequacy of anaesthesia before suturing	In the TAC and LET group combined, 116 of the 151 patients (76.8%) received adequate anaesthesia before suturing. There was no difference between TAC (79.5%) and LET (74.4%) when the proportion of those who had adequate anaesthesia were compared (X2; P=.46)	Limited by the subjective method of pain assessment.
			Analgesic efficacy	Duration of anaesthesia during suturing was classified in 115 of the 116 who had adequate anaesthesia. There was no difference between TAC and LET when the proportions of those defined as complete, partial or incomplete were compared
Eidelman et al, 2005, USA	A systematic review of twenty two trials that randomized 3190 adult and paediatric patients.	Systematic review of randomized controlled trials	Analgesic efficacy	Three double blinded RCTs demonstrated equivalent efficiacy of topical LAT and TAC formulations. Two distinct trials compared topical LAT (lidocaine 4% - epinephrine 1:2000 – tetracaine 0.5%) solution and gel forms with topical TAC. The first reported a non-significant difference in LAT and TAC solutions with respect to patient VAS ratings (mean ranked sum: TAC = 50.8, LAT 45.3; P = .266). The second trial similarly found no significant difference between LAT and TAC gel formulations. The subject quantified pain intensity during wound closure using a 10-point modified multidimensional pain scale (mean ranked sum: TAC = 46.9, LAT = 49.0; P = .71) The third trial recorded absence of pain when the wound was probed with a needle prior to repair (TAC = 79.5%, LAT = 74.4%; P = .46) again demonstrating no significant difference.	The systematic review process may be compromised by heterogeneiity of included studies. There was variability in patient age between studies and pain assessment in younger paediatric patients may not be accurate. There is also a publication bias, with journals more likely to publish studies with positive results than those with negative findings.

Comment(s)

The use of lignocaine, epinephrine, tetracaine gel has been studied extensively in children and has been found to be equally as effective as tetracaine, epinephrine, cocaine gel as a topical anaesthetic for small wounds requiring suturing. Variable combinations of lidocaine (1–4%) epinephrine (1:1000–1:2000) and tetracaine (0.5–2.0%) have been compared favourably with topical application of tetracaine, epinephrine, cocaine gel, without the associated risks and administrative complications of cocaine. lignocaine, epinephrine, tetracaine gel provides an inexpensive alternative to tetracaine, epinephrine, cocaine and the removal of cocaine avoids the need to use controlled drug procedures and the potentially toxic side effects of cocaine, which is known to produce measurable blood levels when applied topically.

Editor Comment

LAT, lignocaine, epinephrine, tetracaine; RCT, randomised controlled trial; TAC, tetracaine, epinephrine, cocaine; VAS, visual analogue scale.

Clinical Bottom Line

Considering costs, abuse potential and the potential for systemic toxicity for tetracaine, epinephrine, cocaine gel, lidocaine, epinephrine, tetracaine gel appears to be the better alternative as a topical anaesthesic used on children requiring closure of small wounds in the emergency department.

References

1. Ernst AE, Marvez E, Nick TG, et al. Lidocaine Adrenaline Tetracaine Gel Versus Tetracaine Adrenaline Cocaine Gel for Topical Anesthesia in Linear Scalp and Facial Lacerations in Children Aged 5 to 17 Years Pediatrics 1995;95:255–8.
2. Schilling CG, Bank DE, Borchert BA, et al. Tetracaine, Epinephrine (Adrenalin), and Cocaine (TAC) Versus Lidocaine, Epinephrine, and Tetracaine (LET) for Anesthesia of Lacerations in Children. Ann Emerg Med 1995 ;25:203-8.
3. Eidelman A, Weiss JM, Enu IK, et al. Comparative efficacy and costs of various topical anesthetics for repair of dermal lacerations: a systematic review of randomized, controlled trials. Journal of Clinical Anesthesia 2005:17: 106-116.