Table 1.

Active pharmaceutical ingredients (APIs) mostly used in acne therapy with specific mechanisms and effects and current pharmaceutical formulations used in dermatologic algorithms.

No.	API	Mechanisms and Effects	Formulations	Ref.
1.	Erythromycin -topical-	Antibacterial Bacterial resistance may occur	Solution with zinc acetate Gel with isotretinoin	[105,106,107,108]
2.	Zinc acetate -topical-	Anti-inflammatory Antioxidant	Solution with erythromycin	[109]
3.	Clindamycin phosphate -topical-	Antibacterial Bacterial resistance may occur	Gel, 1% Gel with tretinoin, 1.2%/0.025% Gel with nicotinamide 1%/4% Gel with benzoyl peroxide 1%/2.5%	[105] [110,111,112,113]
4.	Nicotinamide -topical-	Anti-inflammatory Moisturizer	Gel 4%/5% alone or with clindamycin	[111,112]
5.	Metronidazole -topical-	Antibacterial Anti-inflammatory	Cream, 1% Gel, 1%, 2%	[114,115]
6.	Ivermectin -topical-	Anti-parasitic Anti-inflammatory	Cream, 1%	[116]
7.	Doxycycline -systemic-	Antibacterial Bacterial resistance may occur	Capsules, 100 mg	[117]
8.	Minocycline -systemic- -topical-	Antibacterial Hepatic affection, vestibular events, autoimmune skin disorders may occur Induce photosensitivity	Tablets, 100 mg Foam, 4%	[117,118]
9.	Tetracycline -systemic- -topical-	Antibacterial Affected oral absorption when is administered with food Induce photosensitivity	Capsules, 250 mg Ointment, 3%	[119] [120,121]
10.	Cotrimoxazole -systemic-	Antibacterial Off-label use Just in refractar cases	Tablets, 400 mg/80 mg, 800 mg/160 mg	[122]
11.	Azelaic acid -topical-	Anti-inflammatory, antioxidant Increased erythema may occur Induce photosensitivity	Cream, 20% Gel, 15% Foam, 15%	[123]
12.	Benzoyl peroxide -topical-	Antibacterial Erythema, burning sensations, dryness may occur Induce photosensitivity	Gel, alone or with clindamycin	[113]
13.	Salicylic acid -topical-	Anti-inflammatory Keratoplastic Erythema, dryness may occur	Cosmeceuticals Associated with topical moisturizers Gel, 2%	[124,125,126]
14.	Isotretinoin -systemic- -topical-	Equilibration of desquamation process, by targeting retinoic acid receptors (RAR) (α, β and γ) Anti-inflammatory Erythema, dryness may occur	Capsules 10–40 mg Gel, 0.05% and 0.1% with erythromycin 4%	[93] [127,128]
15.	Tretinoin -topical-	Equilibration of desquamation process, by targeting retinoic acid receptors RAR (α, β and γ) Anti-inflammatory Erythema, dryness may occur	Cream Gel formulation with clindamycin Concentration domain 0.01–0.1%	[127,129]
16.	Adapalene -topical-	Equilibration of desquamation process, by targeting retinoic acid receptors RAR (α, β and γ) Anti-inflammatory Erythema, dryness may occur	Gel with benzoyl peroxide 0.1/2.5% and 0.3/2.5%	[127,129]
17.	Tazarotene -topical-	Equilibration of desquamation process, by targeting retinoic acid receptors RAR (α, β and γ), selectively on β and γ receptors Anti-inflammatory Erythema, dryness may occur	Cream Gel Foam, 0.1%	[127,130]
18.	Trifarotene -topical-	Equilibration of desquamation process, by targeting RAR γ Anti-inflammatory, comedolytic	Cream, 0.005%	[131]
19.	Cortexolone 17α-propionate -topical-	Antiandrogen Anti-inflammatory	Cream, 1%	[132]
20.	Spironolactone -systemic-	Antiandrogen Only women recommended	Tablets, 25–200 mg	[133]
21.	Cyproterone -systemic-	Antiandrogen Headache, edema, hepatic affection, menstrual cycle modification may occur Last line therapy	Tablets, 50–100 mg or combined with ethinylestradiol 2 mg/0.035 mg	[134]
22.	Dapsone -systemic- -topical-	Antibacterial High tolerability	Tablets, 300 mg Gel, 5%, 7.5%	[135,136]