Tretinoin sensitivity

Photosensitivity It is advisable to rest a patient s skin until effects of keratolytic agents subside before beginning tretinoin. Minimize exposure to sunlight and sunlamps, and advise patients with sunburn not to use tretinoin until fully recovered because of heightened susceptibility to sunlight as a result of tretinoin use. Patients who undergo considerable sun exposure due to occupation and those with inherent sun sensitivity should exercise particular caution. Use sunscreen products and wear protective clothing over treated areas. Weather extremes, such as wind and cold, also may irritate treated areas. 

Topical retinoic acid is applied initially in a concentration sufficient to induce slight erythema with mild peeling. The concentration or frequency of application may be decreased if too much irritation occurs. Topical retinoic acid should be applied to dry skin only, and care should be taken to avoid contact with the corners of the nose, eyes, mouth, and mucous membranes. During the first 4-6 weeks of therapy, comedones not previously evident may appear and give the impression that the acne has been aggravated by the retinoic acid. However, with continued therapy, the lesions will clear, and in 8-12 weeks optimal clinical improvement should occur. A timed-release formulation of tretinoin containing microspheres (Retin-A Micro) delivers the medication over time and may be less irritating for sensitive patients. 

One stud)P showed that a tretinoin concentration of 0.01% is effective for the face, hands and forearms, whereas another showed that there is no difference between placebo, 0.01% tretinoin and 0.001% tretinoin. A concentration between 0.05% and 0.1% is, on the other hand, always considered active. The average concentration used is 0.05%, but different skin types or sensitivities may require different concentrations, and it is recommended to start any treatment with a trial dose of 0.02% or 0.03%. 

Tretinoin cream should be kept out of direct sunlight and away from heat sources, to which it is sensitive. In spite of these precautions, it gradually loses its efficacy and it is recommended that the prescription be renewed every 3 months. Tretinoin is sensitive to oxidation, heat and ultraviolet light the refrigerator (4 C) seems to be the best place to store this cream. The by-products of degradation turn the cream a yellowish color, in which case it should no longer be used. 

People who use tretinoin often report that their skin is more sensitive to the sun and burns more easily. This photosensitization is better explained by the thinning of the stratum corneum rather than by a photochemical reaction between the tretinoin and the sun s rays. It is therefore essential to recommend the use of a sunscreen (SPF 25-50 UVA + UVB + HSP induction) to patients being treated with tretinoin. It should also be borne in mind that there is a potential risk of skin cancers developing as a result of the stratum corneum thinning and the enhanced penetration of the sun s rays. Nevertheless, it appears that patients on longterm tretinoin treatment do not have a higher incidence of skin cancers. Tretinoin has in fact proved to be effective in the treatment of photoaging and actinic keratoses. 

Tretinoin (vitamin A acid) makes the skin more sensitive. 

If, on the other hand, a patient cannot tolerate a concentration of tretinoin at 0.05%, applying an 8-10% glycolic acid cream in the morning will make a tretinoin cream at 0.015% applied in the evening more effective, at the same time as reducing the irritation caused by the retinoid. These combinations must always be used under close medical supervision, however, as in dual therapy, skin reactions can be highly unpredictable and severe in some patients. More sensitive skins can be treated as follows ... 

Tretinoin became available as a topical treatment for acne in the United States in 1971. Tretinoin is also known by its chemical name, z)X-trans-retinoic acid. It increases the turnover of skin cells at the surface of the hair follicle. This leads to the extrusion of comedones. Side effects include local skin irritation and increased stm sensitivity. Newer preparations of tretinoin, designed to achieve slow absorption of the drug into epithelial cells, cause less skin irritation than forms available initially. Improvement in acne may not be noticeable until two to three weeks after treatment begins. 

Sensitization to tretinoin (retinoic acid) has been described several times in humans without known pre-exposure (Jordan et al. 1975) and in patients during topical... 

Some active substances are so sensitive to light that light must be excluded to the highest possible extent during preparation. In practice, this means that the preparation should not be done in the vicinity of a window and that artificial lights should be switched off. Examples of pharmaceutical preparations for which this may be necessary are dithranol cream, phytomenadione oral solution and tretinoin solution. 

Caution must be exercised with these kinds of substances and they need to be stored properly and not being used if the expiry date is exceeded. The influence of light should not be underestimated. The Ph. Eur. states for many substances, for example tretinoin, phytomenadione, corticosteroids and benzodiazepines that they must be protected against light. In oils and fats oxidation and peroxide formation is increased by light. Sorbic acid in solution (so also in preparations) is sensitive to light. 

Decreases in hemoglobin concentration were observed in rats treated with 15 or 40 mg isotretinoin/kg/day as early as after 4 weeks of treatment and in rats treated with 4 mg/kg/day after 12 weeks of treatment female rats appeared to be more sensitive than male rats to this effect. In contrast, tretinoin had little or no effect on hemoglobin concentration even after 12 weeks of treatment at 5 mg/kg/day (Hixson et al., 1979). 

Tretinoin peels can be left on for 4-12 hours depending on skin sensitivity. Water can be used to rinse off the yellow-hued tretinoin. 

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