What is pimecrolimus?
Pimecrolimus is a topical steroid-free medication with immune-modulating and anti-inflammatory properties. It is classified as a calcineurin inhibitor. It is an ascomycin macrolactam derivative (ascomycin is produced by Streptomyces hygroscopicus). Pimecrolimus is available in New Zealand as a 1% strength cream in a 15g tube.
How does pimecrolimus work?
Although the mechanism of action of pimecrolimus in the treatment of atopic dermatitis is not yet completely understood, the following immune-modulating effects have been noticed.
- Pimecrolimus at very small concentrations binds with high affinity to the protein receptor macrophilin-12 (FKBP-12).
- This resulting drug-protein complex inhibits calcineurin (a calcium-dependent phosphatase transmitting chemical) that results in the blockage of signal transduction in target cells.
- As a consequence, the release of cytokines (chemicals in the body's immune system that can cause inflammation, redness and itching) from T-cells and mast cells is blocked.
What is pimecrolimus used for?
Pimecrolimus is approved for use for the short-term and intermittent long-term treatment of atopic dermatitis in patients that are over 3 months of age. In some countries, it is only approved for use in the over 2's.
There is no cure for atopic dermatitis, but pimecrolimus provides a steroid-free alternative treatment for controlling the symptoms. It relieves the itch and inflammation caused by atopic dermatitis.
Pimecrolimus cream may prove useful for many other skin conditions that respond to topical steroids (such as other types of eczema/dermatitis) but there is very little published data to confirm this. Dermatologists are likely to recommend pimecrolimus cream in other diseases when there is a poor response to conventional treatments or side effects have arisen.
How to use pimecrolimus cream
Pimecrolimus cream is a prescription medicine and should be used only as directed by your doctor. Pimecrolimus cream may be applied to all skin surfaces including the head, face, neck, around the eyes, and skin folds.
Pimecrolimus should be used as follows:
- Rub a thin layer gently and completely into the affected area(s) twice daily.
- Do not use occlusive dressings (i.e. sticking plasters).
- Wash hand after application if hands are not the treatment sites or if you are applying the cream to someone else.
- Minimize or avoid exposure to natural or artificial sunlight.
- Stop using pimecrolimus cream once signs or symptoms resolve. Use an emollient as maintenance therapy – this can be applied immediately after using pimecrolimus cream.
- Restart treatment when the signs or symptoms recur.
- If the condition does not improve within 6 weeks of treatment or at any time if the condition worsens, stop applying pimecrolimus cream and see your doctor. It may be necessary to use a topical corticosteroid for a short course to control a flare of eczema.
Pimecrolimus cream is odour free, non-greasy, and absorbs quickly into the skin so that it shouldn't stain clothes or bedding.
Precautions if you are using pimecrolimus cream
- Consult your doctor if the atopic dermatitis is infected, who should prescribe an appropriate antimicrobial agent. It may be necessary to stop applying pimecrolimus cream until the skin infection has resolved.
- Treatment with pimecrolimus may be associated with an increased risk of varicella-zoster virus infection (chickenpox), herpes simplex virus infection (cold sores) or eczema herpeticum.
- Avoid use in areas affected by active, cutaneous viral infections such as herpes simplex, molluscum contagiosum or viral warts.
- Protect your skin from sun exposure as the potential effects of pimecrolimus cream on skin response to ultraviolet damage are unknown.
- No data exists regarding pimecrolimus use in immunocompromised patients.
- If you experience any unusual side effects stop the treatment and consult your doctor.
What are the side effects of pimecrolimus cream?
Most patients tolerate pimecrolimus cream well. [See Cutaneous adverse reactions of calcineurin inhibitors]. Initial research indicates it can be used on large areas of the body and for long periods of time without adverse effects, due to low level of absorption internally. However, there is no published data for its use over more than one year.
The most common side effect that can be experienced around the site of the application is a feeling of warmth or a sensation of burning. This is usually mild to moderate in severity and goes away within a few days after starting treatment. However, if this reaction persists for more than one week you should see your doctor. There appears to be a slightly increased susceptibility to skin infections such as folliculitis, impetigo, herpes simplex and molluscum contagiosum.
Other less common reported adverse reactions during research trials have included headache, cough, fever, coldlike symptoms but these were no more likely in patients receiving pimecrolimus than those using a control placebo cream.
Most data published regarding the tolerability of pimecrolimus comes from studies in adult patients. However, limited studies to date concerning infants and children using the cream for up to a year have shown that pimecrolimus appears to be well tolerated in all age groups. The risk for systemic side effects and skin atrophy, problems commonly associated with the use of topical corticosteroids, has not been found with pimecrolimus use. However, as this is a new drug, the full safety profile of the medication is unknown; the main concerns relate to its effect on the immune system. The risk of skin cancer and lymphoma appears to be very low but is being carefully monitored at this time (May 2005).
Pimecrolimus has not been tested in pregnant women but studies have indicated that it is unlikely to have harmful effects on the foetus. It is not known whether it is excreted in breast milk but it is not thought to pose any risk to a baby. Nevertheless, because there isn't much information about this new medication, it is safest to avoid using it when pregnant or breastfeeding.