Nadifloxacin (INN, brand names Acuatim, Nadiflox, Nadoxin, Nadixa, activon) is a topical fluoroquinolone antibiotic for the treatment of acne vulgaris. It is also used to treat bacterial skin infections. In vitro studies of nadifloxacin showed potent and broad-spectrum antibacterial activity against aerobic Gram-positive, Gram-negative and anaerobic bacteria, including Propionibacterium acnes and Staphylococcus epidermidis. Nadifloxacin inhibits the enzyme DNA gyrase that is involved in bacterial DNA synthesis and replication, thus inhibiting the bacterial multiplication. In some European countries, the drug has been approved for the treatment of acne vulgaris. In a 2013 multicenter, randomized clinical study with a total of 184 Japanese patients with moderate to severe acne, adapalene 0.1% gel plus nadifloxacin 1% cream (combination therapy) showed a significant efficacy in decrement of inflammatory papulopustular lesions. Despite this it should be noted that in patients with skin lesions, topical application of nadifloxacin can result in plasma concentrations of 1 to 3 ng/ml. During the treatment some patients may develop some adverse effects predominantly of the skin and subcutaneous tissue: burning and itching (in absolute the most common side effect), contact dermatitis, dryness and skin irritation.