Avita Information
Avita (Tretinoin)
Avita (Tretinoin) Description
Avita (Tretinoin) Cream, a topical retinoid, contains tretinoin 0.025% by weight in a hydrophilic cream vehicle of stearic acid, polyolprepolymer-2, isopropyl myristate, polyoxyl 40 stearate, propylene glycol, stearyl alcohol, xanthan gum, sorbic acid, butylated hydroxytoluene, and purified water. Chemically, tretinoin is all-transretinoic acid (CH0; molecular weight 300.44 vitamin A acid) and has the following structural formula:
Avita (Tretinoin) Clinical Pharmacology
Although the exact mode of action of tretinoin is unknown, current evidence suggests that topical tretinoin decreases cohesiveness of follicular epithelial cells with decreased microcomedo formation. Additionally, tretinoin stimulates mitotic activity and increased turnover of follicular epithelial cells causing extrusion of the comedones.
In vitro
in vivo
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Avita (Tretinoin) Indications And Usage
Avita (Tretinoin) Cream is indicated for topical application in the treatment of acne vulgaris. The safety and efficacy of this product in the treatment of other disorders have not been established.
Avita (Tretinoin) Contraindications
The product should not be used if there is hypersensitivity to any of the ingredients.
Avita (Tretinoin) Precautions
If a reaction suggesting sensitivity or chemical irritation occurs, use of the medication should be discontinued. Exposure to sunlight, including sunlamps, should be minimized during the use of Avita (Tretinoin) Cream, and patients with sunburn should be advised not to use the product until fully recovered because of heightened susceptibility to sunlight as a result of the use of tretinoin. Patients who may be required to have considerable sun exposure due to occupation and those with inherent sensitivity to the sun should exercise particular caution. Use of sunscreen products and protective clothing over treated areas is recommended when exposure cannot be avoided. Weather extremes, such as wind or cold, also may be irritating to patients under treatment with tretinoin.
Avita (Tretinoin) Cream should be kept away from the eyes, the mouth, the paranasal creases, and mucous membranes. Topical use may induce severe local erythema and peeling at the site of application. If the degree of local irritation warrants, patients should be directed to temporarily use the medication less frequently, discontinue use temporarily, or discontinue use altogether. Efficacy at reduced frequencies of application has not been established. Tretinoin has been reported to cause severe irritation on eczematous skin and should be used with utmost caution in patients with this condition.
In a life-time dermal study in CD-1 mice with another tretinoin cream, at 100 and 200 times the average recommended human topical clinical dose, a few skin tumors in the female mice and liver tumors in male mice were observed. The biological significance of these findings is not clear because they occurred at doses that exceeded the dermal maximally tolerated dose (MTD) of tretinoin and because they were within the background natural occurrence rate for these tumors in this strain of mice. There was no evidence of carcinogenic potential when tretinoin was administered topically at a dose five times the average recommended human topical clinical dose. For purposes of comparisons of the animal exposure to human exposure, the "recommended human topical clinical dose" is defined as 1.0 g of 0.025% Avita (Tretinoin) Cream applied daily to a 50 kg person. In a chronic, two-year bioassay of vitamin A acid in mice performed by Tsubura and Yamamoto, generalized amyloid deposition was reported in all vitamin A treated groups in the basal layer of the skin. In CD-1 mice, a similar study reported hyalinization at the treated skin sites and the incidence of this finding was 0/50, 3/50, 3/50, and 2/50 in male mice and 1/50, 0/50, 4/50, and 2/50 in female mice from the vehicle control, 0.25 mg/kg, 0.5 mg/kg, and 1 mg/kg groups, respectively.
Studies in hairless albino mice suggest that tretinoin may enhance the tumorigenic potential of carcinogenic doses of UVB and UVA light from a solar simulator. In other studies, when lightly pigmented hairless mice treated with tretinoin were exposed to carcinogenic doses of UVA/UVB light, the incidence and rate of development of skin tumors were either reduced or no effect was seen. Due to significantly different experimental conditions, no strict comparison of these disparate data is possible at this time. Although the significance of these studies to humans is not clear, patients should minimize exposure to sun.
The mutagenic potential of tretinoin was evaluated in the Ames assay and in the mouse micronucleus assay, both of which were negative.
Dermal Segment I and III studies with Avita (Tretinoin) Cream have not been performed in any species. In oral Segment I and Segment III studies in rats with tretinoin, decreased survival of neonates and growth retardation were observed at doses in excess of 2 mg/kg/day (> 400 times the average recommended human topical clinical dose).
Avita (Tretinoin) Adverse Reactions
The skin of certain sensitive individuals may become excessively red, edematous, blistered, or crusted. If these effects occur, the medication should either be discontinued until the integrity of the skin is restored, or the medication dosing frequency should be adjusted temporarily to a level the patient can tolerate. However, efficacy has not been established for lower dosing frequencies. True contact allergy to topical tretinoin is rarely encountered. Temporary hyper- or hypopigmentation has been reported with repeated application of Avita (Tretinoin) Cream. Some individuals have been reported to have heightened susceptibility to sunlight while under treatment with Avita (Tretinoin) Cream. Adverse effects of Avita (Tretinoin) Cream have been reversible upon discontinuation of therapy (see Section).
Avita (Tretinoin) Overdosage
If medication is applied excessively, no more rapid or better results will be obtained and marked redness, peeling, or discomfort may occur. Oral ingestion of the drug may lead to the same side effects as those associated with excessive oral intake of vitamin A.
Avita (Tretinoin) Dosage And Administration
Avita (Tretinoin) Cream should be applied once a day, in the evening, to the skin where acne lesions appear, using enough to cover the entire affected area lightly. Application may cause a transient feeling of warmth or slight stinging. In cases where it has been necessary to temporarily discontinue therapy or reduce the frequency of application, therapy may be resumed or frequency of application increased when the patients become able to tolerate the treatment. Alterations of dose frequency should be closely monitored by careful observation of the clinical therapeutic response and skin tolerance. Efficacy has not been established for less than once-daily dosing frequencies.
During the early weeks of therapy, an apparent increase in number and exacerbation of inflammatory acne lesions may occur. This is due, in part, to the action of the medication on deep, previously unseen lesions and should not be considered a reason to discontinue therapy. Therapeutic results should be noticed after two to three weeks but more than six weeks of therapy may be required before definite beneficial effects are seen. Patients treated with Avita (Tretinoin) Cream may use cosmetics, but the areas to be treated should be cleansed thoroughly before the medication is applied (see Section).
Avita (Tretinoin) How Supplied
Avita (Tretinoin) (tretinoin cream) Cream, 0.025% is supplied as:
Avita (Tretinoin) Rx Only
MYLAN BERTEK PHARMACEUTICALS INC.Research Triangle Park, NC 27709-4149
Revised April 2005
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Avita (Tretinoin)
