Duac® [Benzoyl Peroxide, Clindamycin]

Pharmacological properties

clindamycin is a lincosamide antibiotic with a bacteriostatic effect against gram-positive aerobic microorganisms and a wide range of anaerobic bacteria. lincosamides, such as clindamycin, bind to the 23s subunit of the bacterial ribosome and inhibit the early stages of protein synthesis. the effect of clindamycin is predominantly bacteriostatic, although high concentrations may have a slow bactericidal effect against sensitive strains.

Although clindamycin phosphate is inactive in vitro, rapid in vivo hydrolysis converts this compound to clindamycin, which is active against bacteria. The antibacterial activity of clindamycin has been clinically demonstrated in the treatment of comedones in patients with acne at levels sufficient for the activity of the drug against most strains of Propionibacteium acnes. Clindamycin in vivo inhibits all tested Propionibacteium acnes cultures (0.4 μg / ml MIC). After the use of clindamycin, the proportion of free fatty acids on the skin surface decreased from approximately 14 to 2%.

Benzoyl peroxide has a mild keratolytic effect against comedones at all stages of their development. It is an oxidizing agent with bactericidal activity against Propionibacteium acnes, which causes the development of acne vulgaris. In addition, it is a sebostatic agent that counteracts excessive sebum production, which is associated with acne.

The addition of benzoyl peroxide reduces the potential for clindamycin-resistant organisms.

Pharmacokinetics Clindamycin has minimal skin absorption. The presence of benzoyl peroxide in the composition of the drug did not affect the percutaneous absorption of clindamycin. Studies with radiolabeling have shown that absorption of benzoyl peroxide through the skin is possible only after it is converted to benzoic acid. Benzoic acid is primarily conjugated to form hippuric acid, which is secreted by the kidneys.

Indications

Local treatment of acne (acne vulgaris) of mild to moderate severity, mainly inflammatory elements in adults and children over the age of 12 years.

Application

For external use only.

Adults and children over 12 years old. Duac is applied 1 time per day in the evening to the affected areas of the skin after thoroughly cleansing and washing the skin with water and drying. If the gel is not rubbed into the skin easily, this indicates an excessive amount.

After applying the gel, wash your hands. The patient may apply a moisturizer if necessary.

In case of excessive dryness or peeling of the skin, the frequency of use should be reduced or treatment should be temporarily discontinued. When used with a frequency of less than 1 time per day, the effectiveness of treatment has not been proven. Use gel no more than 1 time per day.

Patients should be warned that increasing the amount of gel applied does not increase the effectiveness of the drug, but increases the risk of skin irritation.

For the appearance of a therapeutic effect, it may take from 2 to 5 weeks of treatment. The maximum course of treatment is 12 weeks.

Contraindications

Hypersensitivity to the components of the drug and lincomycin. local enteritis, ulcerative colitis or antibiotic-associated colitis (including pseudomembranous colitis) or their history. children under 12 years old.

Side effects

Adverse reactions are summarized when using a combination and separate use of the active ingredients of the drug - benzoyl peroxide and clindamycin. adverse reactions are presented according to the classification of meddra (table. 1). the frequency is defined as follows: very often (≥1 / 10), often (from ≥1 / 100 to 1/10), infrequently (from ≥1 / 1000 to 1/100), rarely (from ≥1 / 10,000 to 1 / 1000), unknown (impossible to determine based on existing data).

Table 1. Adverse reactions when using the active ingredients of the drug - benzoyl peroxide and clindamycin

Organ System Class According to MedDRA	Often	Often	Infrequently	Unknown **
Immune System Disorders				Allergic reactions including hypersensitivity and anaphylaxis
Disorders of the nervous system *			Paresthesia
Digestive disorders				Colitis (including pseudomembranous colitis), diarrhea, hemorrhagic diarrhea, abdominal pain
Disorders from the skin and subcutaneous tissue *	Erythema, peeling, dryness (mainly moderate-intensity events reported)	Burning sensation	Contact dermatitis, pruritus, erythematous rashes, exacerbation of acne	Hives
General disorders and disorders at the site of application				Reactions at the site of application, including discoloration

* At the place of application.

** Based on data from post-marketing research. Since these observations cover populations of unknown size and include mixed factors, it is not possible to reliably estimate their frequency, and systemic reactions were rarely observed.

In addition to the adverse reactions listed in the table above, in the main clinical study of clindamycin 1% gel / benzoyl peroxide 3% gel, photosensitization reactions were often locally observed at the site of application.

Local tolerance. According to the data of 5 clinical studies of Duac gel, all patients were classified according to the degree of erythema, peeling, burning and dryness according to the following scale: 0 - no manifestations, 1 - mild, 2 - moderate, 3 - severe. The percentage of patients with symptoms before and during treatment is presented in table. 2.

Table 2. Durability of Duac gel when applied topically once a day to patients (n = 397) who participated in the III phase of the clinical trial

Side reactions	Before treatment			During treatment
	Mild	Moderate degree	Severe degree	Mild	Moderate degree	Severe degree
Erythema	28%	3%	0	26%	5%	0
Peeling	6%	1%	0	17%	2%	0
Burning sensation	3%	1%	0	5%	1%	0
Dryness	6%	1%	0	15%	1%	0

special instructions

Contact with eyes, mouth, lips, other mucous membranes or areas with irritation or damage should be avoided.