Limitations: This safety classification applies only to preparations containing a combination of the drugs clindamycin, benzoylperoxide and tretinoin. The same ATC code (D10AF51) can in some countries be used for different combinations of clindamycin and other drugs, which in theory may or may not be porphyrinogenic. Please refer to the classification and monograph of each individual substance.

Combination preparations containing clindamycin in conjunction with benzoyl peroxide or tretinoin are considered probably not porphyrinogenic due to insignificant hepatic exposure after topical application.

Clindamycin is a lincosamide antibiotic Benzoylperoxide is a dibenzoyl peroxide Tretinoin is a retinoid

The combination of clindamycin and benzoylperoxide or tretinoin is used in the treatment of mild to moderate acne vulgaris. The gels are administered topically.

After 14 consecutive days with applications of a gel containing 10 mg clindamycin and 0.25 mg tretinoin the maximal plasma concentrations were 3.5 ng/mL and 1.6 ng/mL, respectively (SPC). This is equivalent to 0.008 µM and 0.005 µM, respectively, and hepatic exposure is insignificant. Following a four-week dosing period for clindamycin 10 mg/g and benzoyl peroxide 50 mg/g the percutaneous absorption of clindamycin was negligible (0.043 % of applied dose) (SPC).

Clindamycin has been found to induce CYP3A4 in vivo and is classified probably porphyrinogenic when used systemically (for more details see monograph with ATC code: J01FF01). Clindamycin for dermal use is classified as probably not porphyrinogenic due to minimal hepatic exposure (ATC-code: D10AF01). Benzoyl peroxide for dermal use is classified as not porphyrinogenic due to insignificant hepatic exposure (ATC-code: D10AE01). Tretinoin for dermal use is classified as probably not porphyrinogenic due minimal percutaneous exposure (ATC-code: D10AD01).