What can be the effects of using Aknemycin for more than 12 weeks and can it be combined with Acnelec or Duac?

There have been no studies confirming the safety of Aknemycin for a period of more than 4-6 weeks. Nevertheless, the drug is practically not absorbed into the general circulation, it only causes a local effect - so it can be guessed that long-term use may be associated with, for example, a higher risk of skin irritation, dry skin or reduced sensitivity to the drug (which will make the therapy less effective). However, it does not pose a threat to the health and life of the patient. Aknemycin can be used together with Acnelec. Then the dosage regimen should be followed, using one preparation in the morning and the other in the evening. However, Do not combine Aknemycin with Duac. According to the manufacturer of Duac: "Duac should not be used concomitantly with medicines containing erythromycin (e.g. Aknemycin) due to the potential for clindamycin antagonistism." Duac should also not be combined with Acnelec: "The concomitant use of Duac with tretinoin, isotretinoin and tazarotene should be avoided as benzoyl peroxide may reduce their effectiveness and increase skin irritation. If it is necessary to use products containing these substances concomitantly, they should be applied at different times of the day (e.g. one in the morning and the other in the evening)." I also attach a link to a helpful post: https://www.gdziepolek.pl/artykuly/jak-pozbyc-sie-tradziku-u-doroslych