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A Double-Blind, Randomized, Placebo-Controlled Trial of Eutectic Lidocaine/Prilocaine Cream 5% (EMLA) for Analgesia Prior to Cryotherapy of Verrucae Plantaris in Adults

21 Years
Open (Enrolling)
Plantar Warts

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Trial Information

A Double-Blind, Randomized, Placebo-Controlled Trial of Eutectic Lidocaine/Prilocaine Cream 5% (EMLA) for Analgesia Prior to Cryotherapy of Verrucae Plantaris in Adults


The study is a single-centre, double-blind, randomized, placebo-controlled, parallel-group
trial with one visit. The investigators planned to include at least 64 patients in 4 months.
Adult patients (at least 21 years old) diagnosed with plantar warts are potential subjects
for the study.

Once a potential subject is identified, the field investigator will assess him/her for
eligibility to enter the study. Then, the potential subject will be provided with full and
adequate verbal and written information about the nature, purpose, possible risks and
benefits of the study. If the subject agrees to enroll into the study, a signed informed
consent will be obtained from him/her.

All patients are randomly assigned by computer-generated randomization sequence to receive
either eutectic lidocaine/prilocaine cream (EMLA)® 5% or placebo 60 mins prior to
application of cryotherapy. The plantar warts are pared with shape blade before applying
EMLA®or placebo cream. Based on the randomization, an designated dermatology laboratory
technician will apply either the EMLA® cream 5% or placebo cream to the wart lesions. The
cream is applied as a thick layer to the wart and to the surrounding 1 to 2 mm and left on
for 60 minutes under occlusion of Tegaderm dressing. The cream is then removed, and liquid
cryotherapy applied using cryospray. The lesions are treated with double freeze-thaw cycle.
The end point of each freeze is a complete ice-ball covering the lesion with 1-2mm
peripheral extension. The study involved only one treatment with either placebo or EMLA®
cream 5% followed by cryotherapy as described. No other analgesic other than the EMLA® cream
5% or placebo is allowed at least 2 hours prior to or during cryotherapy.

A 100 mm visual analogue pain scale (VAS) is used to denote pain severity ranging from "no
pain" (0 mm) to the "worst possible pain" (100 mm). The patient will choose a distance from
the "no pain" anchor closest to the pain experienced during cryotherapy for wart removal.
Pain is evaluated in each participant using a self-administered VAS immediately after
cryotherapy treatment.

Potential Benefits:

The potential benefits are:

1. The patients may experience less pain during application cryotherapy.

2. The application of local anesthetic cream may possibly increase the effectiveness of

Potential Risks:

EMLA cream® is known to be relatively safe with minimal side effects. The commonest side
effect would be local irritation to the skin e.g. redness, itchiness which is reversible
after removal of the cream. Very rarely (<1000), severe allergic reaction can occur with
application of EMLA cream® (AstraZeneca information brochure).

Inclusion Criteria:

1. Adult patients (at least 21 years old) with plantar warts

2. They must agree for liquid nitrogen cryotherapy for treatment of the plantar warts

3. The patients have to be capable of assessing pain using a visual analogue pain scale

Exclusion Criteria:

1. Patients who had previously used EMLA cream® prior to cryotherapy of warts

2. Known allergic sensitivity to EMLA cream® or amide type of local anaesthetics.

3. Patients with sensory peripheral neuropathy of both lower limbs.

Type of Study:


Study Design:

Allocation: Randomized, Intervention Model: Single Group Assignment, Masking: Double Blind (Subject, Caregiver, Investigator)

Outcome Measure:

Pain Visual Analogue Score(VAS)

Outcome Description:

At the end of the treatment i.e.Pain VAS will be assessed 60 mins after application of the study cream

Outcome Time Frame:

At the end of the treatment (day 1)

Safety Issue:


Principal Investigator

Chen Wee Aw, MBBS

Investigator Role:

Principal Investigator

Investigator Affiliation:

National University Hospital, Singapore


Singapore: Health Sciences Authority

Study ID:




Start Date:

February 2010

Completion Date:

December 2010

Related Keywords:

  • Plantar Warts
  • EMLA
  • plantar warts
  • cryotherapy
  • Warts
  • Foot Diseases