Acne is a chronic, self-limiting inflammatory disease of pilosebaceous unit.1 It is multifactorial, of which Propioniobacterium acne and Sebum play an important role in etiopathogenesis. Vitamin A plays a role in keratinisation.2 The various retinoid preparations available are tretinoin, isotretinoin, adapalene and tazarotene.3, 4
Mechanisms of action of retinoic acid are: Restoration of disturbed keratinisation, increase in cell turnover and decrease in cohesiveness of stratum corneum, and regulation of prostaglandin synthesis.5, 6 Topical retinoids have the following effects: Reduces the number and formation of precursor lesions, reduces mature comedones, exhibits anti-inflammatory effect and promotes normal desquamation of follicular epithelium.7 Tretinoin is a first-generation topical retinoid available in 0.025%, 0. 05%, 0 .1% strengths in cream, gel and liquid formulation. Adapalene (synthetic naptholic acid derivative) is a third-generation topical retinoid. It is available as a 0. 03% and 0.1% alcoholic gel.
Aims and Objectives
The aim of the study is to compare efficacy of Tretinoin and Adapalene in Acne Vulgaris and to compare the side effects of topical tretinoin and adapalene.
Materials And Methods
Randomised prospective comparative clinical trial with sample size of 50 patients who are recruited from department of dermatology of Meenakshi Medical College and Research Institute, Kanchipuram, Tamil Nadu, India. All the patients attending the Outpatient Department of Dermatology in Meenakshi Medical College and Research Institute, with Acne grade 1 and grade 2 lesions were included in the study. Consent was obtained from the patients prior to enrolment into the study. Patients were randomly selected and grouped to avoid and minimise bias as much as possible. First 25 patients who came to study centre, within the study period, having acne, fulfilling inclusion and exclusion criteria, willing to apply topical retinoids irrespective of age, sex, occupation or grade of Acne were given topical adapalene 0.1% and last 25 patients were grouped for topical tretinoin 0.04%.
According to the number of acne lesions on the face, patients were graded into grade 1 and grade 2 initially. Grade 1 has only comedones and few papules. Grade 2 has comedones, many papules and few pustules. Grades were calculated every 4 weeks and recorded respectively at 0, 4, and 8 weeks. Reduction percentage was calculated by calculating the percentage reduction in the average number of lesions from GR-0 to GR-4.
Side effects were recorded at 4th week and 8th week. Clinical photographs of the lesions were taken before the commencement of therapy and after the completion of therapy.
hows the data of pre-therapeutic grading. Out of 25 patients using adapalene, 12 patients were Grade I and 13 were grade II. Out of 25 patients usingtretinoin, 12 patients were Grade I and 13 were grade II. (Table 1).
In table 2 data pertaining to post therapeutic grading was shown. Out of 25 patients using adapalene, 14(56%) were reduced to grade 0, 9(36%) were reduced to grade I and only 2(8%) accounts for grade II. (Table 2).
On the other hand, out of 25 patients using tretinoin only 7(28%) patients were reduced to grade 0, 12(48%) were in grade I and 6 (24 %) patients accounts for grade II.
Mean Reduction Rate:
The mean of comedones was initially 7.20, which reduced to 5.68 at 4th week and which further reduced to 3.12 at 8th week. The mean of papules was initially 2.92, which reduced to 1.96 at 4th week and which further reduced to 0.76 at 8th week. The mean of pustules was initially 0.72, which reduced to 0.24 at 4th week and which further reduced to 0.04 at 8th week.
The mean of comedones was initially 6.88, which reduced to 5.68 at 4th week and which further reduced to 4.12 at 8th week. The mean of papules was initially 3.04, which reduced to 2.40 at 4th week and which further reduced to 1.92 at 8th week. The mean of pustules was initially 0.56, which reduced to 0.40 at 4th week and which further reduced to 0.32 at 8th week.
Following were the side effects reported after topical application of adapalene and tretinoin and were duly recorded with every patient. Comparative chart of side effects occurring after topical application of adapalene and tretinoin in total number of patients is shown in Table 3 and Table 4. Side effects were more commonly seen in patients who applied topical tretinoin than in patients who applied topical adapalene.
Out of 25 patients using adapalene, side effects were seen in 8 patients (32%).
Out of 25 patients using tretinoin, side effects were seen in 18 patients (72%).
In our study, Side effects were more commonly seen in patients who applied topical tretinoin than in patients who applied topical adapalene. In a study done by Dunlap FE, Mills OH1, adapalene 0.1% gel showed significantly less irritating to the skin in terms of producing erythema, dryness, desquamation and burning/stinging (P< 0.02). 32 patients experienced mild to moderately severe adverse events, 3patients had adverse events considered to be drug related (two with skin discomfort; one with skin dryness). This study showed that a majority of patients preferred adapalene 0.1% gel over tretinoin 0.025 % cream and that it caused significantly less skin irritation.
In another study by Jain S 2 it was found that tretinoin 0.05% gel exhibits a greater anti-acne efficacy than adapalene 0.1% gel, but has higher skin irritation potential.8
In another study performed by Tu P, Li GQ, side effects such as Erythema, burning, pruritus, scaling and dryness were more common and more severe in the tretinoin group vs. the adapalene group. Adapalene offers comparable efficacy to tretinoin, but is less irritating. It represents a good alternative for the treatment of mild to moderate acne vulgaris in Chinese patients.9
In the present study there was a reduction in the number of all types of lesions, i.e., come done, papule and pustule. Present study, the group that applied topical Adapalene showed better lesion reduction compared to that showed by the group that applied topical Tretinoin. In a study done by Shalita and Weiss J S, adapalene gel produced numerically greater lesion reduction than did tretinoin gel for all lesion types.10
In another study by Grosshans E, Marks R, the efficacy of adapalene gel was found to be superior to tretinoin gel after one week of treatment, with respect to reduction in inflammatory lesion.11
In one more study conducted by W.J. Cunliffe and R. Caputo 5, it was found that Adapalene gel 0.1% was significantly more effective in treating acne lesions than 0. 03% adapalene gel. Adapalene gel 0.1 % was significantly more effective than 0.025% or tretinoin gel in one study and of the same effectiveness in the other study.
From the present study following conclusions can be made:
Adapalene 0. 1% produced numerically greater lesion reduction than tretinoin 0. 04% for all lesion types. Thus, Adapalene was found superior to Tretinoin in reducing average number of lesions.
Highest reduction in number of lesions with both topical retinoids was for comedones (p< 0. 001) followed by papules (p<0. 001) and pustule (p= 0.001).
In Patients who applied adapalene, most of them were reduced to grade 0 and grade I and only few were in grade II. Whereas in patients who applied tretinoin only few were reduced to grade 0 and many were in grade I and grade II.
Side effects were more commonly seen in patient treated with topical Tretinoin than with topical Adapalene.
Adapalene showed significantly less irritation to the skin in terms of producing erythema, dryness, photosensitivity, itching and burning. Adapalene was better tolerated than tretinoin. Hence adapalene is a safe and effective in treatment of acne.
Author would like to express their deepest gratitude to the study subjects for their participation and co-operation.