Pharmacy Clinic
Vitamin A analogues
•        Have been used successfully to treat acne for many years.
•        Tretinoin (Retin-A(R)), also called all-trans-retinoic acid, is the naturally occurring form
of vitamin A acid and is considered the most effective topical comedolytic agent.
•        Unlike benzoyl peroxide, retinoids have no in vitro antibacterial properties.
•        Retinoids indirectly reduce P. acnes colonization by decreasing sebum production, a
requisite for bacterial survival.
•        They also decrease horny cell cohesiveness by stimulating epidermal cell turnover and
normalizing keratinization.
•        These actions unplug follicles, which ultimately prevents microcomedone formation;
•        reduce inflammation by directly inhibiting neutrophil and monocyte chemotaxis.
•        considered highly effective agents because their pharmacologic activities target each of
the four known pathogenic factors previously described.
•        Indicated for mild to moderate comedonal acne and should be used in patients who
have become resistant to, or cannot tolerate, benzoyl peroxide or antibiotics.
•        Tretinoin is available as cream (0.025%, 0.05% and 0.1%), gel (0.01% and 0.025%)
and liquid (0.05%) to be applied before retiring once a day to skin that has been washed.
•        Trial therapy should begin with bedtime application of the 0.01% gel formulation for
four to eight weeks before a stronger formulation is used.
•        The peak clinical improvement is generally delayed and is evident at three to four
months.
•        Adverse effects with retinoid therapy occur in nearly all patients, with dryness, redness
and peeling at the site of application topping the list. Tretinoin decreases the thickness of
the stratum corneum, the most superficial layer of the skin, rendering the skin vulnerable,
•        Exposure to sunlight can significantly intensify irritation to the skin. If sun exposure is
unavoidable, patients should use a sunscreen with an SPF of at least 15.
•        Topical tretinoin may further darken skin in patients with dark complexion.
•        Patients should be made aware that improvement may take six to 12 weeks, and that
flare-ups of acne can occur during the first few weeks of therapy.
•        Can be used in combination with benzoyl peroxide or antibiotics for severe
inflammatory acne,
•        Enhancing the penetration of many compounds through the skin.
•        The combination of benzoyl peroxide and tretinoin shows an additive and synergistic
effect on inflammatory acne when used on a daily basis,
•        benzoyl peroxide in the morning and the tretinoin at night.
•        A microsphere 0.1% tretinoin gel subsequently was developed, liposome encapsulation
enhancing penetration into the skin and decreasing irritation at the applied site.
Acne treatment