Melatonin has been shown to prevent cellular damage produced by oxidative stress or in situations of ischaemia, inhibiting the synthesis of oxidants and pro inflammatory factors such as pro-inflammatory cytokines, substances which are present in pressure ulcers and can affect the healing process, slowing it down. Melatonin gel has also been shown to prevent ulcers in the oral mucosa due to radiotherapy. Therefore, the hypothesis for this study is that the melatonin cream provides greater ulcer area reduction than standard pressure ulcer treatment.

Melatonin has been shown to prevent cellular damage produced by oxidative stress or in situations of ischaemia, inhibiting the synthesis of oxidants and pro inflammatory factors such as pro-inflammatory cytokines, substances which are present in pressure ulcers and can affect the healing process, slowing it down. Melatonin gel has also been shown to prevent ulcers in the oral mucosa due to radiotherapy. Therefore, the hypothesis for this study is that the melatonin cream provides greater ulcer area reduction than standard pressure ulcer treatment.

In order to o determine the efficacy of melatonin in healing pressure ulcer it has been designed a multicentre, single-blind, randomized clinical trial comparing melatonin cream as an experimental pressure ulcer treatment versus control group with standard treatment based on moist environment wound healing with a time frame of 8 weeks. In order to assess the healing rate, changes in Resvech 2.0 scale scores will be measured, as well as the ulcer surface reduction. To avoid variability in measuring ulcer surface, it will be done by using software HELCOS after taking a photograph of the wound weekly. An intention-to-treat analysis will be carried out. The t-test or Mann-Whitney will be used to check difference of means in the reduction of the area of the ulcer and variation in the Resvech 2.0 scale. Survival curves will be used to check possible differences in the follow-up time until epithelization.

Inclusion Criteria:

• Present at least one category II, III or IV pressure ulcer according to National Group for the Study and Assessment of Pressure Ulcers (GNEAUPP) classification.
• Ulcer area between 1 and 100 cm2.
• People over 18 years of age who have freely given their informed consent in writing of their own volition or it has been given on their behalf by a legal guardian

Exclusion Criteria:

• Ulcer of category I, non-classifiable or affecting internal tissues, but with no break in the skin
• People currently undergoing chemotherapy treatment or who have done so in the previous 6 months
• People with a presumed life expectancy of less than 6 months or in palliative care.