Other combination therapies may lack convenience but are also effective. In the patient with comedones and inflammatory lesions, a comedolytic agent such as tretinoin, adapalene or azelaic acid may be combined with benzoyl peroxide or a topical antibiotic. The combination of clindamycin and tretinoin causes less irritation than tretinoin alone. 30 In using tretinoin and the benzoyl peroxide–erythromycin combination together, the patient should alternate the products daily for two weeks to minimize irritation. When agents that cause irritation are used, patience is necessary, but the results may be well worth the wait.