To which class of antibiotics does minocycline belong?

Minocycline Belongs to the Tetracycline Class of Antibiotics

Minocycline is a second-generation, semi-synthetic tetracycline antibiotic. 1, 2

Classification and Chemical Structure

• Minocycline is classified as a tetracycline derivative with the chemical name 4,7-Bis(dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,10,12,12a-tetrahydroxy-1,11-dioxo-2-naphthacenecarboxamide monohydrochloride 1
• It is a semisynthetic derivative of tetracycline that has been in therapeutic use for over 30 years 2
• As a member of the tetracycline class, minocycline shares the core four-ring structure characteristic of all tetracyclines 1

Mechanism of Action

• Like other tetracyclines, minocycline exerts its antimicrobial effect primarily by inhibiting bacterial protein synthesis 1
• It works by binding to the 30S subunit of the bacterial ribosome, which prevents the attachment of aminoacyl-tRNA to the mRNA-ribosome complex 3
• In addition to its antimicrobial properties, minocycline demonstrates notable anti-inflammatory effects, including inhibiting chemotaxis and metalloproteinase activity 3

Clinical Applications

• Minocycline is indicated for the treatment of moderate to severe acne vulgaris, as recommended by the American Academy of Dermatology 3, 4
• It is used in the treatment of infections caused by Acinetobacter baumannii resistant to carbapenems 5
• The American Thoracic Society recommends minocycline for the treatment of pulmonary diseases caused by non-tuberculous mycobacteria 5
• It is also used for the treatment of blepharitis 5

Antimicrobial Spectrum

• Minocycline has activity against a wide range of Gram-positive and Gram-negative bacteria 1
• It is effective against organisms including Acinetobacter species, Enterobacter aerogenes, Escherichia coli, Haemophilus influenzae, Klebsiella species, and Neisseria meningitidis 1
• It also has activity against other microorganisms such as Actinomyces species, Chlamydia trachomatis, and Mycoplasma pneumoniae 1

Comparison to Other Tetracyclines

• Minocycline differs from other tetracyclines in its side effect profile, with more frequent reports of vertigo, dizziness, and pigment deposition 3, 6
• Unlike doxycycline, minocycline has been associated with black discoloration of breast milk due to iron pigment deposition in macrophages 7
• Minocycline has less photosensitizing potential compared to other tetracyclines, particularly doxycycline 3, 6
• It has been associated with more serious adverse events than other tetracyclines, including tinnitus, dizziness, vertigo, and pigment deposition of the skin, mucous membranes, and teeth 3

Important Precautions

• Like all tetracyclines, minocycline is contraindicated in children under 8 years of age due to the risk of permanent tooth discoloration and enamel hypoplasia 5, 1
• It is classified as pregnancy category D and should not be used during pregnancy 4, 1
• Minocycline has been associated with drug-induced lupus erythematosus more frequently than other tetracyclines 8
• It should be used with caution in patients with renal or hepatic insufficiency 5, 1

Minocycline represents an important member of the tetracycline class with unique properties that distinguish it from other tetracyclines while maintaining the core mechanism of action and structural characteristics of this antibiotic class.