Condition category
Infections and Infestations
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Not provided at time of registration

Trial website

Contact information



Primary contact

Prof Jorg Heukelbach


Contact details

Departamento de Saúde Comunitária
Faculdade Medicina
Rua Prof. Costa Mendes 1608
5. andar

Additional identifiers

EudraCT number number

Protocol/serial number

CAAE - 1422.0.000.040-06 179/06

Study information

Scientific title

Efficacy of a pediculicide based on dimeticone: randomised observer-blinded comparative trial in patients with severe infestation


DIMPED (DIMeticone for the treatment of PEDiculosis)

Study hypothesis

The efficacy against head lice infestation of a product containing a high (92%) concentration of the silicon oil dimeticone (similar to Nyda®) is similar or superior to a product containing 1% permethrin.

Ethics approval

Ethics approval received from the Ethical Review Board of the Federal University of Ceará (Brazil) on the 14th September 2006 (ref: 179/06). Registered in the database of the Brazilian Ministry of Health for studies involving human subjects (“Sistema Nacional de Informações Sobre Ética em Pesquisa envolvendo Seres Humanos” [SISNEP]), accessible under (project no: 1422.0.000.040-06).

Study design

Randomised, controlled, observer-blinded clinical trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting

Not specified

Trial type


Patient information sheet


Active head lice infestation


Participants were recruited from a poor urban neighbourhood in Brazil where head lice are highly prevalent. To minimise reinfestation during the trial, study participants were transferred to a holiday resort outside the endemic area for a period of nine days.

Participants were randomised to receive either topical treatment with a product containing a high percentage of dimeticones (92%), equivalent in composition to Nyda® (G. Pohl-Boskamp GmbH & Co. KG, Hohenlockstedt, Germany), or topical permethrin 1% aqueous solution (Kwell®, GlaxoSmithKline, Brazil). Two topical applications were done, seven days apart. Participants were treated immediately upon arrival at the resort (day 1) and, a second time seven days later (day 8) to kill newly hatched lice from eggs which may have survived the first treatment.

The products were used according to the producers' recommendations. The fine tooth comb provided by both producers together with the pediculicide was not used after the topical application of the products. The dimeticone-based product was applied to dry hair and then left to dry naturally. After eight hours the hair was washed with a commercial shampoo not containing dimeticones. Kwell® was applied to wet hair, left for 30 minutes and thereafter washed out in an identical manner as the other product. Both products were applied systematically onto the hair from the hair shafts to the tips, and a normal comb was used to spread the liquids evenly.

The dimeticon-based product (in composition similar to Nyda® , G. Pohl-Boskamp GmbH & Co. KG, Hohenlockstedt, Germany) was prepared at the Department of Pharmacy of the Federal University of Ceará by an experienced pharmacist, the permethrin product bought locally at a pharmacy.

Intervention type



Not Specified

Drug names

Dimeticone product equivalent in composition to Nyda®, topical permethrin

Primary outcome measure

The primary outcome measure was defined as the proportion of participants cured of head lice infestation one, six and eight days after the first treatment (i.e. days 2, 7 and 9, respectively). Cure was defined as the complete absence of viable lice on the scalp, as determined by wet combing with a high quality plastic head louse comb.

Secondary outcome measures

1. Reduction of clinical pathology: days 1 (before intervention), 2, 4, 7 and 9
2. Reduction of the degree of itching (assessed based on a pre-tested ordinal Visual Analogue Scale [VAS] ranging from 0 to 4): days 1 (before intervention), 2, 3, 4, 5, 6, 7, 8 and 9
3. Cosmetic acceptability of the products, assessed using a summary score ranging from -4 (extremely negative) to +4 (extremely positive), with a standardised questionnaire including subjective assessment of smelling, irritation of scalp, cosmetic changes of hair, and changes in the easiness to comb the hair: days 2, 4, 7 and 9
4. Safety (number and type of adverse events). Clinical pathology included the presence of erythema, papules, excoriations, eczema, secondary infection and enlarged cervical or retro-auricular lymph nodes: days 2, 4, 7 and 9 (and continuous documentation when any adverse event [AE] occurred, indendent from timepoints).

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Children aged 5 - 15 years, either sex
2. An active head lice infestation (one or more active head lice found after three minutes of visual inspection)
3. Written consent obtained from study participants and carers

Participant type


Age group




Target number of participants

146 children and adolescents

Participant exclusion criteria

1. Use of head lice products, anthelminthics, or antibiotics within the previous four weeks
2. Severe skin disorders of the scalp (such as generalised impetigo, eczema, psoriasis or chronic dermatitis of unknown origin)
3. Bleached or colour treated hair within the previous four weeks
4. Known sensitivity to any ingredients in the products
5. Mental disease
6. Drug abuse
7. Pregnant or lactating girls
8. Unwillingness to stay for nine days in a holiday resort outside the endemic area where the clinical trial would be carried out
9. Participation in another clinical study in the previous month

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Departamento de Saúde Comunitária

Sponsor information


Mandacaru Foundation (Brazil)

Sponsor details

Rua José Vilar de Andrade 257

Sponsor type

Research organisation



Funder type

Research organisation

Funder name

Mandacaru Foundation (Brazil)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Basic results (scientific)

Publication list


Publication citations

  1. Results

    Heukelbach J, Pilger D, Oliveira FA, Khakban A, Ariza L, Feldmeier H, A highly efficacious pediculicide based on dimeticone: randomized observer blinded comparative trial., BMC Infect. Dis., 2008, 8, 115, doi: 10.1186/1471-2334-8-115.

Additional files

Editorial Notes