minocycline
Brand: Minocin, Dynacin, Solodyn
Prototype: doxycycline
Drug Class: tetracycline antibiotic
Drug Family: antibiotic
Subclass: semisynthetic tetracycline (long-acting)
Organ Systems: infectious-disease
Mechanism of Action
Reversibly binds 30S ribosomal subunit, blocking aminoacyl-tRNA attachment and inhibiting protein synthesis; bacteriostatic. Greater lipophilicity than tetracycline or doxycycline enables broader tissue distribution and enhanced activity against MRSA.
30S ribosomal subunit
Indications
- acne vulgaris
- community-acquired pneumonia (atypical)
- MRSA skin and soft tissue infections (mild-moderate)
- rosacea
- rheumatoid arthritis (adjunct)
- gonorrhea (penicillin-allergic)
- meningococcal carrier state
Contraindications
- tetracycline hypersensitivity
- pregnancy (permanent tooth discoloration in fetus)
- children <8 years (tooth discoloration)
- concurrent isotretinoin (increased intracranial hypertension risk)
Adverse Effects
Common
- GI upset
- dizziness/vertigo (vestibular side effects unique to minocycline)
- photosensitivity
- skin/mucous membrane discoloration
Serious
- drug-induced lupus erythematosus
- autoimmune hepatitis
- drug reaction with eosinophilia and systemic symptoms (DRESS)
- pseudotumor cerebri (intracranial hypertension)
- permanent tooth discoloration (children, in utero)
Pharmacokinetics (ADME)
| Absorption | 90–100% oral bioavailability; food has minimal effect |
| Distribution | highly lipophilic; distributes widely including CNS, skin, prostatic fluid |
| Metabolism | hepatic (partial); partially by CYP enzymes |
| Excretion | renal (less than doxycycline) and fecal |
| Half-life | 11–23 hours |
| Onset | 1–2 hours |
| Peak | 1–4 hours |
| Duration | 12 hours |
| Protein Binding | 76% |
| Vd | large |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| isotretinoin | additive risk of pseudotumor cerebri; contraindicated combination | major |
| antacids/calcium/iron supplements | divalent/trivalent cations chelate tetracyclines, reducing absorption | major |
| warfarin | tetracyclines potentiate warfarin effect via gut flora suppression | moderate |
Nursing Considerations
- Take on an empty stomach or with food (does not significantly affect absorption unlike older tetracyclines); separate from antacids, calcium, magnesium, iron, and dairy by at least 2 hours.
- Warn patients about vestibular side effects (dizziness, vertigo, ataxia) — unique to minocycline among tetracyclines; these usually resolve upon dose reduction or discontinuation.
- Advise patients to use sunscreen and protective clothing; photosensitivity is a class effect.
- Counsel women of childbearing age: minocycline is absolutely contraindicated in pregnancy — confirm pregnancy status before prescribing.
Clinical Pearls
- Minocycline is unique among tetracyclines in causing vestibular toxicity (dizziness, vertigo, ataxia), related to its lipophilicity and CNS penetration; onset is usually within the first few doses.
- Long-term use for acne or arthritis may cause skin, nail, and scleral discoloration (blue-gray pigmentation) due to minocycline-melanin chelate deposits.
Safety Profile
Pregnancy contraindicated
Lactation avoid
Renal Adjustment Not required
Hepatic Adjustment Required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.