Increased activity of the sebaceous or oil glands
Blockage of the pores due to increased cellular
proliferation, resulting in the formation of comedone or blackhead
Growth of a bacterium called P. acnes within the
Drugs used in acne act through different mechanisms:
Antimicrobials like benzoyl peroxide, clindamycin,
erythromycin and sodium sulfcetamide inhibit the growth of P. acnes
Dapsone acts by reducing inflammation. It may also
reduce the levels and activity of P. acnes.
Benzoyl peroxide acts against the bacteria and
exerts a mild effect on comedones.
Retinoids such as adapalene, tazarotene and
tretinoin act at multiple sites to treat acne. They reduce the cellular
proliferation, inhibit formation of comedones and have anti-inflammatory
effect. Retinoids are now available as emollient creams and microsphere gel to
reduce irritation and improve efficacy.
combination of medications is used, it will not only be effective through multiple
mechanisms, it will also help to simplify treatment and improve patient
adherence to treatment.
A combination of benzoyl peroxide and clindamycin
has been found to be more effective than benzoyl peroxide alone. Benzoyl
peroxide, through its effect on bacteria, may also help to reduce bacterial
resistance when used in combination.
of clindamycin phosphate 1.2%, an antimicrobial and tretinoin 0.025% has been
approved for the treatment of acne
. Clindamycin acts as an antibacterial and anti-inflammatory
agent, whereas tretinoin acts against comedones. The treatment has been found
to be effective in various studies.
The combination is applied once a day either in the
morning or at bedtime. Side effects include acne flare, sunburn, allergic
reaction, skin reactions and increased sensitivity to ultraviolet light. The
combination should not be used in patients suffering from Crohn's disease,
ulcerative colitis, colitis with previous antibiotic use, and use of
erythromycin containing products at the same time.
of the drug adapalene 0.1% with benzoyl peroxide 2.5% has been recently
approved for use as a once-a-day treatment in the US and Canada
. Adapalene acts against
comedones as well as has anti-inflammatory properties. The combination acts on
multiple mechanisms: It prevents comedone formation, growth of bacteria and
inflammation. The most common adverse effect associated with this combination
is dry skin.
combinations of anti-acne medications for local applications have not only been
found to be effective, they may also probably increase patient's adherence to
1. Fu LW and Vender RB. Newer Approaches in Topical Combination Therapy
for Acne. http://www.skintherapyletter.com/2011/16.9/2.html