Minocin

Approved Indications

• Moderate to Severe Acne Vulgaris (inflammatory type) in adolescents and adults.
• Respiratory Tract Infections:
  Including pneumonia and bronchitis caused by susceptible organisms.
• Urinary Tract Infections (UTIs) caused by susceptible Gram-negative bacteria.
• Skin and Soft Tissue Infections, such as cellulitis or wound infections.
• Sexually Transmitted Infections (STIs):
• Urethritis and cervicitis caused by Chlamydia trachomatis or Ureaplasma urealyticum.
• Lymphogranuloma venereum
• Syphilis (in penicillin-allergic patients)
• Rickettsial Infections:
  Rocky Mountain spotted fever, typhus fever, Q fever.
• Anthrax (including post-exposure prophylaxis).
• Plague, Cholera, Brucellosis (as combination therapy).

Clinically Accepted Off-label Uses

• Rheumatoid Arthritis (early-stage) as a disease-modifying agent.
• Multidrug-Resistant Acinetobacter and MRSA Infections in specific clinical settings.
• Neuroinflammatory and Neurodegenerative Conditions (investigational use) such as ALS and Huntington's disease due to anti-inflammatory properties.

Adults

• Initial dose for general infections:
  200 mg orally once or 100 mg twice on the first day.
• Maintenance dose:
  100 mg every 12 hours or 50 mg four times daily.
• Route: Oral or intravenous.
• Duration: 7–14 days based on indication.

Acne Vulgaris

• Extended-release tablets: 1 mg/kg orally once daily.
• Immediate-release capsules/tablets: 50–100 mg orally once or twice daily.
• Duration: Several weeks or months as required.

Pediatrics (≥8 years)

• Initial: 4 mg/kg/day (maximum 200 mg/day) divided into 2 doses on Day 1.
• Maintenance: 2 mg/kg/day divided every 12 hours.
• Not recommended for children <8 years due to tooth discoloration risk.

Renal Impairment

• Use with caution. Accumulation may occur. Monitor renal function and reduce dose if toxicity signs appear.

Hepatic Impairment

• Use cautiously. Monitor liver function tests, especially with prolonged use.

Minocycline is a semisynthetic tetracycline antibiotic that inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit. This prevents the attachment of aminoacyl-tRNA to the ribosome, effectively halting bacterial growth. Minocycline is bacteriostatic and has a broad spectrum of activity. Its high lipophilicity allows for enhanced tissue penetration, including the central nervous system. It may also exhibit anti-inflammatory and neuroprotective effects in certain conditions.

• Absorption:
  High oral bioavailability (~90–100%). Food may slightly delay absorption but does not significantly reduce extent.
• Tmax:
  1–4 hours post-dose.
• Distribution:
  Extensive tissue distribution, including into skin, saliva, and CNS.
  Protein binding: ~76%.
• Metabolism:
  Hepatically metabolized with enterohepatic circulation. Produces both active and inactive metabolites.
• Elimination:
  ~10–15% excreted unchanged in urine; remainder via feces.
  Half-life: ~11–23 hours.

• Pregnancy:
  FDA Category D – Evidence of fetal risk (tooth discoloration, inhibited bone growth).
  Use only if benefits outweigh risks and no safer alternatives exist.
• Lactation:
  Excreted in breast milk. Risk of dental and bone growth issues in infants.
  Avoid use during breastfeeding.

• Primary Class: Antibiotic
• Subclass: Tetracycline Derivative (Second-generation)

• Known hypersensitivity to minocycline, other tetracyclines, or formulation excipients.
• Children under 8 years (unless no alternative exists).
• Pregnancy (especially 2nd and 3rd trimesters).
• Severe hepatic impairment.
• Concurrent use with isotretinoin (risk of pseudotumor cerebri).

• Photosensitivity:
  May cause sunburn-like reactions. Avoid direct sunlight.
• Pseudotumor Cerebri:
  Risk of benign intracranial hypertension. Discontinue if symptoms like headache or vision changes occur.
• Autoimmune Reactions:
  Drug-induced lupus-like syndrome, autoimmune hepatitis, and vasculitis have been reported.
• Vestibular Toxicity:
  Dizziness, vertigo, and imbalance are common—especially at higher doses.
• Superinfection Risk:
  Prolonged use may result in overgrowth of resistant organisms, including Candida or C. difficile.
• Tooth Discoloration:
  Irreversible staining in developing teeth in children and fetuses.
• Hepatotoxicity:
  Monitor liver enzymes during long-term therapy or if liver dysfunction is suspected.

Common

• GI: Nausea, vomiting, diarrhea, abdominal pain
• CNS: Dizziness, vertigo, drowsiness
• Skin: Rash, photosensitivity, skin discoloration
• Musculoskeletal: Arthralgia, fatigue

Serious or Rare

• Hepatitis or hepatic failure
• Drug-induced lupus erythematosus
• Stevens-Johnson syndrome
• Anaphylaxis
• Pseudotumor cerebri
• Thrombocytopenia, neutropenia

• Oral Contraceptives:
  May reduce effectiveness. Advise backup contraceptive use.
• Antacids, iron, calcium, zinc supplements:
  Impair absorption. Administer 2–3 hours apart.
• Isotretinoin:
  Avoid co-administration—risk of increased intracranial pressure.
• Penicillins:
  May antagonize bactericidal action—avoid concurrent use.
• Warfarin:
  Enhanced anticoagulant effect—monitor INR closely.
• Enzyme involvement:
  Not a major CYP450 substrate, inducer, or inhibitor.

• 2023 AAD Guidelines for Acne:
  Minocycline remains a first-line oral antibiotic option for moderate to severe acne.
• 2022 CDC STI Guidelines:
  Minocycline is an alternative in Chlamydia treatment when doxycycline is contraindicated.
• IDSA Updates (2022–2023):
  Still considered a secondary agent in multidrug-resistant Acinetobacter infections.

• Temperature:
  Store at 20°C to 25°C (68°F to 77°F); excursions allowed between 15°C and 30°C.
• Humidity & Light:
  Protect from moisture and direct light. Store in original container.
• Handling Precautions:
• Swallow tablets/capsules whole with a full glass of water to reduce esophageal irritation.
• Do not use expired minocycline; degradation products may cause Fanconi-like syndrome.
• No refrigeration needed.