Differin® - (IR): composition and pharmaceutical form
Differin® - (IR) comes in two forms for external use — a cream and a gel. In both cases one gram of the base contains 1 mg of adapalene, which means the concentration is the same and only the texture of the product differs.
The composition includes propylene glycol and methyl parahydroxybenzoate. These excipients are capable of causing allergic reactions, and sometimes they appear not straight away but as a delayed-type reaction. Both the cream and the gel are intended for application to the skin only.
How Differin® - (IR) works
The active substance of the medicine is adapalene, a derivative of naphthalenecarboxylic acid. It is stable: it does not react with oxygen and is not broken down by light. Its mechanism is close to that of the retinoids — inside the cell adapalene binds to the nuclear retinoic acid receptors (RAR), after which gene expression changes and the synthesis of new mRNA begins. Unlike the retinoids proper, however, the substance does not bind to the cytoplasmic receptors.
The practical sense of this mechanism is twofold. First, adapalene normalises the keratinisation and differentiation of the epidermis and, to all appearances, the differentiation of the epithelium of the hair follicles — it is precisely there that comedones form, and they become fewer. Second, it has a marked anti-inflammatory action, stronger than that of the retinoids: the chemotactic and chemokinetic reactions of the polymorphonuclear leucocytes and the peroxidation of arachidonic acid are suppressed, which means fewer inflammatory mediators are formed. That is why the medicine works both on blackheads and on inflamed elements — papules and pustules.
Indications
The medicine is prescribed in acne vulgaris of mild and moderate severity — in the comedonal form and in the papulopustular one.
Severe acne and eruptions covering a large area of skin are not among the indications. In such cases an external preparation is not enough, and the treatment plan is decided by a doctor. The comedonal form consists mainly of open and closed comedones without marked inflammation; the papulopustular form is when inflamed nodules and pustules are added to them. Both respond to external therapy if the process is limited in area.
Method of use and dosage
The medicine is applied once a day, preferably in the evening, and a small amount of the product is used — as a thin layer, not a thick one. Before this the skin is washed and dried with a towel, after which one waits 10–15 minutes: the product should not be applied to damp skin. The areas around the eyes and lips, and also the nasolabial folds, are not treated. Immediately after application the hands are washed, so that the medicine does not get into the eyes on accidental contact. The course is a long one: if there is no improvement after three months of treatment, the decision on continuing it is taken by the doctor.
| Question | What the leaflet says |
|---|---|
| How often to apply it | Once a day, better in the evening |
| When to apply it after washing | After 10–15 minutes, on dry skin |
| Which areas to avoid | Around the eyes and lips, the nasolabial folds |
| When to assess the result | After 3 months; further use is decided by the doctor |
| From what age | From 12 years; it is not prescribed to younger children |
Contraindications
The medicine is not used in the following conditions:
- hypersensitivity to adapalene or to any component of the cream or the gel;
- a severe form of acne vulgaris;
- acne spread over a large surface of the skin;
- broken skin in the area of application;
- tanned skin;
- eczema and other non-acne eruptions where the product is to be applied;
- pregnancy.
Special warnings and precautions
The product is applied to the skin only and kept away from the eyes, the lips and the mucous membranes; on accidental contact they are rinsed with plenty of water. A short while after the course begins the face may redden and irritation and dryness may appear — this is a common reaction at the start of treatment. The medicine is then withdrawn for several days, one waits until the skin settles, and use is resumed.
- under the action of adapalene the horny layer becomes thinner and the skin reacts more strongly to ultraviolet light, to external medicines and to cosmetics;
- excessive sun and ultraviolet exposure are avoided during treatment, and a hat and protective filters are used;
- cosmetics for problem skin and products with an astringent action are not used alongside the medicine;
- the propylene glycol and methyl parahydroxybenzoate in the composition can be a cause of allergy, including a delayed one;
- the cream and the gel are not prescribed to children under 12;
- the medicine has virtually no influence on the ability to drive and to operate machinery.
Drug interactions
Products with a similar mechanism of action and other external preparations containing retinoids are not used at the same time as this medicine. Products that irritate the skin — exfoliating and astringent preparations, abrasive cleansers, cosmetics containing alcohol — are likewise excluded for the duration of the course.
If other acne medicines have been prescribed in parallel, they are separated by time of day: erythromycin 4%, clindamycin phosphate 1% and benzoyl peroxide 10% are applied in the morning, and adapalene in the evening.
Pregnancy and breastfeeding
Taken by mouth in large doses, adapalene had a toxic effect in animal studies. Clinical data on external use in pregnant women are scarce; what there is does not point to harm to the course of the pregnancy or to the health of the foetus in the early stages. But precisely because the data are limited the medicine is not used during pregnancy, and if a pregnancy occurs, treatment is stopped.
The passage of adapalene into breast milk with external use has not been studied. No influence on the child is to be expected: applied to the skin, the systemic effect on the mother's body is negligible, so the medicine is permitted for breastfeeding women. The only restriction is not to apply the product to the breast area, so that the child does not come into contact with it during feeding.
Adverse effects
All the reactions described are local: they arise in the area of application or on the eyelids if the product accidentally reaches them.
- common — dryness and irritation of the skin, a burning sensation, redness;
- uncommon — contact dermatitis and eczema from irritation;
- uncommon — skin discomfort, itching, flaking, sunburn, a flare of the acne;
- frequency not known — soreness of the skin, swelling of the skin, allergic contact dermatitis;
- frequency not known — irritation, redness, itching and swelling of the eyelids.
The data on the reactions of unknown frequency were obtained after the medicine came onto the market. Mild redness and flaking in the first weeks are to be expected and usually pass on their own; marked irritation that does not settle after several days' break is a reason to see a doctor. A flare of the acne at the start of the course is also possible and does not mean that the product is unsuitable, but it is worth discussing with a doctor.
Overdose
Applying it more often or more generously does not speed up the result or make it better. The only thing it leads to is noticeable redness, flaking and other signs of skin irritation.
In experiments on mice and rats toxic manifestations arose with oral doses of more than 10 g per kilogram of body weight. If the medicine has been swallowed accidentally, gastric lavage is considered and medical help is sought.
How to get a prescription for Differin® - (IR) online
External retinoids are dispensed on prescription because they are not suitable for every form of acne and call for rules of use that a doctor explains.
During the online consultation the doctor will assess the nature of the eruptions, will ask about the products used before and about the accompanying skincare and, if there are no contraindications, will issue an electronic prescription — the medicine can be collected from a pharmacy using its code.
