Does EMLA reduce the discomfort associated with local-anaesthetic infiltration?

The influence of a eutectic mixture of lidocaine and prilocaine on minor surgical procedures: a randomized controlled double-blind trial

BACKGROUND

A eutectic mixture of lidocaine and prilocaine (EMLA) has been shown to be effective in reducing pain from needle sticks, including those associated with blood sampling and intravenous insertion.

OBJECTIVE

To evaluate the effectiveness of EMLA cream applied before needle puncture for local anesthetic administration before minor surgical procedures in this double-blind, randomized, controlled, parallel-group study.

MATERIALS AND METHODS

Patients were randomly assigned to receive EMLA or placebo cream (Aqueous) applied under an occlusive dressing. After the procedure, patients were asked to rate the needle prick and procedure pain on a visual analog scale (0=no pain; 10=maximum pain).

RESULTS

A total of 94 minor surgical procedures (49 in EMLA and 45 in control) were performed. The mean needle-stick pain score in the EMLA group was significantly lower than in the control group (2.7 vs. 5.7, p<.001, Mann-Whitney U-test). There was also significantly lower procedure pain in the EMLA group than in the control group (0.83 vs. 1.86, p=.009). There were no complications associated with the use of EMLA.

CONCLUSION

EMLA effectively reduces the preprocedural needle-stick pain and procedural pain associated with minor surgical procedures.

EMLA cream prior to digital nerve block for ingrown nail surgery does not reduce pain at injection of anesthetic solution

BACKGROUND

Needle penetration and local anesthetic infiltration are painful steps of digital ring block. The objective of this study was to evaluate the efficacy of EMLA cream application prior to digital ring block for surgery for ingrown big toenail.

METHODS

We conducted a prospective, double-blinded, placebo-controlled, randomized clinical trial with 81 patients (range: 12-75 years, mean +/- SD: 30.3 +/- 17.5 years), who underwent big toenail surgery. Prior to the digital block, EMLA cream (Group E) or a placebo cream (Group P) was applied. A visual analog scale (VAS) and a verbal rating score (VRS) from 1 to 10, 10 being most severe pain, were used for assessment of pain during the skin needle penetration and during the infiltration of the anesthetic product.

RESULTS

Data of the VAS and of the VRS during the two steps, respectively, show no significant difference in pain rating between the two groups. In Group E, the gender of the patients had a significant effect on pain perception. Male patients reported less pain than female patients, both during the needle skin penetration and during the infiltration step (P < 0.005). In Group P, reported pain did not differ by gender in either step of the procedure.

CONCLUSIONS

We found no clinical benefit in using EMLA during digital nerve block. Although the digital nerves are not deeply located in the small subcutaneous space of the digit, topical anesthesia may not reach them. Moreover, swelling due to injection of the anesthetic product in this small space may also amplify the sensation of pain.

A blinded, randomized, paired, placebo-controlled trial of 20-minute EMLA cream to reduce the pain of peripheral i.v. cannulation in the ED

A eutectic mixture of local anesthetics (EMLA) in cream form has been used as a topical anesthetic to reduce the pain of procedures penetrating the skin. It is generally applied for 45 to 60 minutes before the painful procedure. The purpose of this study was to determine whether a 20-minute application of EMLA is useful in reducing the pain of routine peripheral intravenous cannulation in the emergency department (ED). A blinded, randomized, placebo-controlled, paired trial compared the pain of intravenous cannulation in both hands of study subjects: one hand was treated with 20-minute EMLA cream and the other hand was treated with 20-minute placebo cream. Forty subjects identified the more painful hand and scored pain measurements of each hand using a 10-cm visual analog scale. These data failed to demonstrate any significant benefit of EMLA compared with placebo. EMLA is not useful for intravenous cannulation when used for 20-minute application times. There may be more effective and less costly ways of reducing the pain of intravenous cannulation that patients would prefer.

Skin grafting of full thickness burns under local anaesthesia with EMLA cream

Two elderly patients with 6 and 4 per cent total body surface area (TBSA) full thickness burns were entirely skin grafted solely under topical anaesthesia with EMLA cream. Both patients had several concurrent illnesses. The risk of general or regional anaesthesia for their general condition was much greater than the risk of unhealed burn wounds which substantially impaired the patients' quality of life. The surgical procedures were painless to both patients. The taking of the skin grafts and the healing of the donor sites were uneventful. It seems that the late skin grafting of full thickness burns up to 10 per cent TBSA may be accomplished solely under the topical anaesthesia with EMLA cream and thus avoiding the general or spinal anaesthesia in a high risk group of thermally injured patients.

Efficacy of EMLA cream prior to dorsal penile nerve block for circumcision in children

BACKGROUND

While circumcision may be performed solely with dorsal penile nerve block (DPNB), some painful steps in its use are skin needle penetration and infiltration of the anesthetic product. The objective of this study was to evaluate the efficacy of EMLA cream, prior to DPNB for circumcision in children.

METHODS

We conducted a prospective, randomized, double-blinded, placebo-controlled study with 42 children undergoing circumcision with DPNB alone, as an ambulatory procedure. Overall efficacy of EMLA cream (Group A) during needle penetration and infiltration was assessed using a visual analog scale, compared with a placebo cream (Group B). Patients were asked to orally report any pain during skin needle penetration and infiltration of anesthetic, and were graded from 1 to 4 according to intensity of pain, as 1) none, 2) slight, 3) moderate, or 4) severe. The child graded the global discomfort of the entire procedure using the visual analog scale.

RESULTS

When assessing needle penetration, none from Group A suffered any pain, whereas all from Group B suffered at least mild pain. Considering infiltration of the anesthetic, all children suffered at least slight-to-moderate pain. Based on the children's visual analog scale scores, EMLA cream has no beneficial effect for penile block.

CONCLUSION

Since the dorsal penile nerves are located under the Buck's fascia, topical anesthesia may not reach them and other techniques may be necessary to anesthetize them. We found that although EMLA cream is efficient as a topical anesthesia during needle penetration for DPNB, it has no beneficial effect during infiltration.

Prilocaine/lidocaine patch as a local premedication for skin biopsy in children

BACKGROUND

Prilocaine-lidocaine emulsion (EMLA) has been used successfully as a local anesthetic in patients undergoing superficial procedures.

OBJECTIVE

The purpose of this study was to investigate the analgesic effect of the patch as a local anesthetic for children undergoing a skin biopsy procedure. The effect on both the pain at the injection site and the pain of the biopsy was investigated.

METHODS

The study was randomized, double blinded, and placebo controlled. Of the 63 children randomly recruited into the study, 60 children were evaluated; the remaining three were withdrawn from the study.

RESULTS

The anesthetic patch was significantly more effective than the placebo patch in decreasing pain at the injection site. No significant difference in pain scores of the biopsy procedure was found between the study groups. No serious side effects were observed.

CONCLUSION

The anesthetic patch reduced the pain experienced by children subjected to a skin biopsy procedure.

Drug management in skin surgery

Lidocaine (lignocaine) 1% with epinephrine (adrenaline) 1:200,000 (maximum dose 40mL) is the agent of choice in skin surgery. It can be used at all sites except the fingers, toes and penis, where epinephrine should be avoided. Epinephrine-induced vasoconstriction delays local anaesthetic clearance, thus prolonging its effect and, by reducing peak blood lidocaine concentrations, enables a higher maximum dose to be used. Adding epinephrine, however, introduces the possibility of a drug interaction with tricyclic antidepressants and nonselective beta-blockers. Also, injection pain is greater because of the acidic sodium metabisulphite that has to be added to prevent epinephrine oxidation. Injection pain can be reduced by buffering the solution using sodium bicarbonate. There are no drug interactions that prevent the use of plain lidocaine: injection pain is least with 0.5% solutions. Injection of large volumes of very dilute lidocaine solutions (tumescent anaesthesia) enables higher maximum doses of lidocaine to be tolerated and large areas to be anaesthetised by infiltration. Amethocaine gel is a faster acting and more effective topical anaesthetic compared with eutectic lidocaine-prilocaine cream, but is a topical sensitiser. In high risk patients, prophylactic antibiotics should be given to prevent bacterial endocarditis when operating on infected lesions and on potentially colonised crusted lesions in high-risk patients (i.e. those with prosthetic heart valves). Wound infections following surgery on infected skin lesions can be prevented by the prophylactic use of mupirocin ointment. Aspirin-induced inhibition of platelet adhesion results in bleeding complications in approximately 15% of skin surgery patients receiving aspirin. Patients whose bleeding time is > 8 minutes are particularly at risk, and aspirin should be stopped at least 7 days prior to surgery in these patients. Aspirin can be continued in other patients without serious bleeding complications.

Eutectic lidocaine/prilocaine 5% cream and patch may provide satisfactory analgesia for excisional biopsy or curettage with electrosurgery of cutaneous lesions. A randomized, controlled, parallel group study

BACKGROUND

Needle puncture and infiltrational anesthesia is generally required for minor cutaneous surgical procedures and may be associated with anxiety, fear, discomfort, and pain. The use of topical anesthetics such as eutectic lidocaine/prilocaine 5% cream may provide an alternative means of delivering anesthesia.

OBJECTIVE

Our purpose was to evaluate the effectiveness of eutectic lidocaine/prilocaine 5% cream applied under either occlusive adhesive dressing (Tegaderm) or patch formulation in providing analgesia for removal of lesions 40 mm long or shorter on the trunk or extremities; removal was effected by excisional biopsy or curettage with electrosurgery.

METHODS

One hundred six patients (58 men, 48 women), 22 to 90 years of age, participated in this open-labeled, randomized, controlled, parallel group study. Patients were randomly assigned to receive either 2.5 to 5 gm of cream applied under an occlusive dressing or a 1.0 gm single-dose-unit patch. The topical anesthetic was removed 2 to 3 hours after application and just before surgery. This area was then tested for analgesia to pinprick. If analgesia was insufficient to the pinprick or during the surgical procedure, lidocaine infiltration was given. Patients rated the pain of the surgical procedure on a 100 mm visual analog scale.

RESULTS

After application times of 110 to 180 minutes, effective anesthesia was achieved in 87% of subjects. Treatment with the patch was equal to the cream/Tegaderm dressing in reducing pain experienced during surgery. No significant difference was found between the adhesiveness of the two dressings; however, the patch was easier to apply than the cream/ Tegaderm. No unexpected adverse events were observed.

CONCLUSION

For minor skin surgical procedures involving excisional biopsy or curettage with electrosurgery, eutectic lidocaine/prilocaine 5% cream/Tegaderm and patch formulations were equally effective and provided effective anesthesia in 87% of subjects. The patch formulation may be more convenient for self-application.

EMLA cream on the ears--is it effective? A prospective, randomised controlled trial of the efficacy of topical anaesthetic cream in reducing the pain of local anaesthetic infiltration for prominent ear correction

A prospective, randomised, double blind trial was carried out to test whether or not the application of topical anaesthetic cream (EMLA cream) before infiltration of local anaesthetic would decrease the discomfort of correction of prominent ears under local anaesthetic. 23 patients were entered into the trial. They acted as their own controls, one ear having EMLA cream applied approximately 2 h prior to surgery, and the other Aqueous cream. Immediately after surgery, the patients were asked to complete two scales describing the amount of pain they had felt in each ear, both at the time of injection of local anaesthetic and during the surgery. They were also asked whether they thought the inconvenience associated with the use of the EMLA cream was worth any improvement they felt. The results showed that, compared to the placebo cream, EMLA cream significantly decreased the pain felt both at the time of injection (p < 0.005) and during the surgery (p < 0.01). However, only 62% of patients asked felt that the inconvenience associated with the use of EMLA cream was worth the benefits that it conveyed.

A multicentre randomized study of single-unit dose package of EMLA patch vs EMLA 5% cream for venepuncture in children

Eutectic mixture of local anaesthetics (EMLA) cream with Tegaderm was compared with pre-packaged EMLA patch with regard to analgesic effect, adhesiveness and local reactions during venepuncture in 178 children from three to ten years. One EMLA patch, or half the contents of a 5 g tube of EMLA cream plus Tegaderm was applied to the dorsum of one hand or antecubital fossa for a minimum of 60 min before venepuncture. The subject and observer assessed the degree of pain on a three-point verbal rating scale. The adhesion of the patch vs Tegaderm to the skin and local reactions were recorded. There was no difference between the two groups in pain associated with venepuncture; 95% of the EMLA patch group and 94% of the EMLA cream group reported no or slight pain. There was no difference between the two treatment groups in terms of overall local reactions. The patch was less adhesive (P < 0.001), but this had no apparent influence on its effectiveness. In conclusion, EMLA patch is equivalent to 5% EMLA cream (2.5 g) in cutaneous pain relief when used for venepuncture in children.

Eutectic lidocaine/prilocaine cream. A review of the topical anaesthetic/analgesic efficacy of a eutectic mixture of local anaesthetics (EMLA)

Eutectic lidocaine/prilocaine cream 5% is a eutectic mixture of the local anaesthetics lidocaine (lignocaine) 25 mg/g and prilocaine 25 mg/g that provides dermal anaesthesia/analgesia following topical application. The principal indication in which eutectic lidocaine/prilocaine cream has been studied is the management of pain associated with venipuncture or intravenous cannulation, where significantly greater pain relief than placebo, with equivalent efficacy to ethyl chloride spray and lidocaine infiltration, has been demonstrated. In dermatological surgery, eutectic lidocaine/prilocaine cream offers effective pain relief in children undergoing curettage of molluscum contagiosum lesions, and in adults undergoing split-skin graft harvesting. Particular benefit has also been shown with use of eutectic lidocaine/prilocaine cream in association with treatment of condylomata acuminata in both men and women, and it appears to provide a useful alternative to lidocaine infiltration in this context. Further research in such indications as paediatric lumbar puncture, minor otological surgery, and minor gynaecological, urological and andrological procedures is likely to further broaden the profile of clinical use for eutectic lidocaine/prilocaine cream. Eutectic lidocaine/prilocaine cream has a very favourable tolerability profile, transient and mild skin blanching and erythema being the most frequent adverse events to occur in association with its application to skin. The potential for inducing methaemoglobinaemia, attributed to a metabolite of the prilocaine component of the formulation, prohibits its use in infants younger than 6 months. In summary, eutectic lidocaine/prilocaine cream is a novel formulation of local anaesthetics that has proven to be effective and well-tolerated in the relief of pain associated with various minor interventions in adults and children.