eMedExpert Home > Medications Facts > Minocycline (Dynacin)

Minocycline is a semisynthetic second-generation tetracycline antibiotic. Minocycline's antimicrobial spectrum is very similar to that of doxycycline with one important addition: it has much more antistaphylococcal activity.

The first tetracycline, chlortetracycline, was discovered in 1948 during systematic screening of soil specimens for antibiotic-producing microorganisms. Chlortetracycline and oxytetracycline come from Streptomyces aureofaciens and Streptomyces rimosus, respectively. Tetracycline is produced semisynthetically from chlortetracycline. Doxycycline and minocycline are both semisynthetic derivatives of tetracycline.

Minocycline was synthesized by Lederle Laboratories in 1967 and became widely available under the brand name Minocin in 197216.

Lederle Laboratories, founded in 1902, is a pharmaceutical division of Cyanamid, a large diversified American chemical manufacturer.

• Rocky Mountain spotted fever, typhus fever and the typhus group, Q fever, rickettsialpox and tick fevers
• Respiratory tract infections: laryngotracheitis, tracheobronchitis, bronchitis, bronchiolitis, bronchiectasis, bronchopneumonia, pneumonia (single lobe and multilobe), lung abscess.
• Psittacosis (Ornithosis)
• Trachoma
• Inclusion conjunctivitis
• Nongonococcal urethritis, endocervical, or rectal infections in adults
• Relapsing fever
• Chancroid
• Plague
• Tularemia
• Cholera
• Campylobacter fetus infections
• Brucellosis
• Bartonellosis
• Granuloma inguinale
• Urinary tract infections: cystitis, pyelonephritis
• Skin and skin structure infections: abscess, acne (including cystic and pustular types), cellulitis, infected dermatitis, folliculitis, furunculosis, impetigo, lymphadenitis, suppurative hydradenitis, paronychia, infected wounds.
• Gonococcal infections
• Syphilis
• Yaws
• Listeriosis
• Anthrax
• Vincent’s infection
• Actinomycosis
• Infections caused by Clostridium species
• Intestinal amebiasis: Minocycline may be a useful adjunct to amebicides.
  Acne

Minocycline is one of the most effective antibiotics used for acne treatment. This antibiotic has been in use since the 1970's and is usually prescribed for the treatment of moderate to severe acne vulgaris.

Minocycline kills the acne bacteria and has a separate anti-inflammatory effect. It reduces the redness, swelling and tenderness or pimples whether it kills the acne bacteria or not.

Minocycline has been proven to be as effective as tetracycline and doxycycline for the quantitative reduction of inflammatory acne lesions. It is considered to produce a more rapid and sustained improvement in acne symptoms.17-18

Most strains of P. acnes are sensitive to minocycline. It is extremely important becuase of increasing rate of P. acnes resistance to tetracycline, doxycycline and erythromycin.

Currently, minocycline has become an extremely controversial treatment for acne. This is primarily related to the fact that a number of studies have now reported that this drug can lead to the development of many serious side effects.

Rheumatoid arthritis

Minocycline is used as a disease-modifying anti-rheumatic drug (DMARD) in the treatment of rheumatoid arthritis. Rheumatoid arthritis is a chronic inflammatory disease affecting about 1% of the adult population.

Although rheumatoid arthritis is not an infection, minocycline may improve the signs and symptoms of this disease. It may slow the progression of joint damage in arthritis and prevent disability. There is evidence that, besides its antibiotic effects, minocycline can modify some of the body's inflammatory responses. It decreases the production of substances causing inflammation, such as prostaglandins and leukotrienes, while increasing production of interleukin-10, a substance that reduces inflammation.

Results of a 48-week multicenter clinical study20 of 219 adults with rheumatoid arthritis show that minocycline reduces joint pain and swelling and is safe in mild to moderate disease. Minocycline may improve control of disease activity and provide relief from swollen, tender joints.

According to the American College of Rheumatology, "Minocycline is prescribed for patients with symptoms of mild rheumatoid arthritis. It is sometimes combined with other medications to treat patients with persistent symptoms of this form of arthritis."

• Osteoporosis
  Minocycline has been shown to increase bone mineral density, improve bone strength and formation, and slow bone resorption in old laboratory animals with surgically-induced menopause21.
• Lyme disease
  Lyme disease, or borreliosis, is an emerging infectious disease caused by the bacterium Borrelia burgdorferi and is transmitted to humans by the bite of infected blacklegged ticks. Minocycline may be useful for the treatment of Lyme disease19.
• Rosacea
  Rosacea is a common inflammatory condition of the skin on the face that causes redness that looks like a flush or blush. It is sometimes called acne rosacea, which is misleading because rosacea and acne are two totally different conditions. Minocycline reduces the redness, papules, pustules and eye symptoms of rosacea. The antibiotic is usually prescribed for 6 to 12 weeks, the duration and dose depend on the severity of the rosacea. Further courses are often needed as the antibiotics don't cure the disorder.
• Sarcoidosis
  Sarcoidosis is a disease that results from a specific type of inflammation of tissues of the body.
  Studies24 indicate that minocycline may be beneficial for the treatment of cutaneous sarcoidosis.
• Cystic fibrosis22-23
  Cystic fibrosis (also known as CF, mucoviscoidosis, or mucoviscidosis) is a hereditary disease that affects mainly the exocrine (mucus) glands of the lungs, liver, pancreas, and intestines, causing progressive disability due to multisystem failure.
• Periodontitis
  Periodontitis is a dental disorder that results from progression of gingivitis, involving inflammation and infection of the ligaments and bones that support the teeth. Minocycline is used to control bacteria and reduce the size of periodontal pockets. The periodontist puts the minocycline micro-spheres into the pockets after scaling and root planing. The particles release minocycline slowly over time.

Advantages:

• Very effective. Minocycline has several advantages over other tetracyclines in the treatment of acne, including more rapid clinical improvement, superior efficacy and effective absorption with or without food.
• Less photosensitizing. Photosensitivity is least likely with minocycline than with other tetracyclines25-26.
• High concentrations in the tissues. Minocycline is widely distributed in body tissues27, with higher concentrations being found in cerebrospinal fluid and sputum than with other tetracycline antibioticss. As in blood, the concentration in tissues is generally 2 to 4 times higher with minocycline than with tetracycline. Equivalent blood and tissue levels achieved whether administered intravenously or orally.
  
• Long half-life (from 11 to 23 hours).
• Broader spectrum of antimicrobal activity. Against certain pathogens, minocycline is more potent than the other tetracyclines. Minocycline has excellent in vitro inhibitory activity against both Staphylococcus aureus and coagulase-negative staphylococci, particularly methicillin-resistant S. aureus and methicillin-resistant S. epidermidis strains3-5.
  
• Can be used in renal impairment. Minocycline, like doxycycline and unlike other tetracyclines, can be used in patients with renal impairment (malfunction of the kidneys). Doxycycline and minocycline are eliminated through the hepatobiliary and gastrointestinal tracts. Most tetracyclines should be avoided in patients with renal insufficiency.
• Less likely to cause bacterial resistance. Minocycline produces less antibiotic resistance than tetracycline.28-29 Bacterial cell membranes contain a lipid layer. One mechanism of building up a resistance to an antibiotic is to produce a thicker lipid layer. This layer makes it difficult for an antibiotic to penetrate. Minocycline chemical structure makes it the most lipid soluble of all the tetracyclines.

Disadvantages:

• Expensive. Minocycline is considerably more expensive than the other generic tetracyclines.
• Contraindicated in children. May cause enamel hypoplasia and permanent teeth discoloration.
• Lupus-like syndrome. Minocycline is more likely than other tetracyclines to produce a lupus-like syndrome. Minocycline-induced lupus is characterized by the development of non-specific symptoms after long-term consumption of the drug, and the patient usually continues to take minocycline despite their illness as the association is not immediately obvious1. These abnormalities tend to occur after prolonged therapy (often longer than 12 months).
• Serum sickness-like reaction. Minocycline induced serum sickness like reaction (SSLR) was first reported in 199030. This is a type of delayed allergic reaction, in which the immune system interprets the antibiotic as a foreign threat. A serum sickness-like reaction (SSLR) to drug usually consists of cutaneous rash, arthralgia/arthritis, and, often, fever.
• Photosensitivity. Minocycline may increase sensitivity to sunlight, resulting in more frequent sunburns or the development of rashes following sun exposure.
• Intracranial hypertension (pseudotumor cerebri) is an accumulation of fluid around the brain. Minocycline can cause the rare condition of secondary intracranial hypertension31 which has initial symptoms of headache, visual disturbances, and confusion.
• Dizziness and other vestibular side effects. Minocycline can cause quite severe dizziness, nausea, vertigo and vomiting32. Vertigo has been reported in as many as 86% of individuals in some series33.
• Hyperpigmentation. Unlike other tetracyclines, minocycline can cause a potentially irreversible slate-grey hyperpigmentation of the skin. Blue or blue-black oral pigmentation was seen in 10% of patients taking minocycline for at least 1 year; the rate increased to 20% after 4 years of continuous use2. Large daily doses of ascorbic acid (vitamin C) may prevent this phenomenon34.

Antibacterial

The tetracyclines are primarily bacteriostatic and are thought to exert their antimicrobial effect by the inhibition of protein synthesis.

Minocycline is a semisynthetic derivative of tetracycline and is active against many tetracycline resistant strains of organisms such as staphylococci, streptococci and E. coli. Thus the combined results of many studies show its activity against approximately 87% of tetracycline resistant staphylococci. Minocycline is also active against many strains of staphylococci which are resistant to penicillin G and certain semisynthetic penicillins.

Neuroprotective effect

Minocycline and other tetracycline derivatives have neuroprotective effects unrelated to their antimicrobial properties. Minocycline has the greatest permeability of all tetracyclines through the blood-brain barrier and is well suited for treatment of CNS disorders.

Minocycline can reduce neuronal death after excitotoxicity and ionizing radiation in culture6-7 and in animal models of stroke7-9, Parkinson's disease10-11, Huntington's disease12, and amyotrophic lateral sclerosis13. The neuroprotective effects of minocycline have been attributed both to reduced inflammation and a direct effect on neuronal survival.

Anti-inflammatory effect

Minocycline induces anti-inflammatory and antinociceptive effects unrelated to its antimicrobial activitiy15. Although the exact mechanisms of minocycline anti-inflammatory effects are still poorly understood, they may include the inhibition of matrix metalloproteinase-2 activity, the inhibition of inducible nitric oxide synthase14, prostaglandin E2, caspase-1, caspase-3, and COX-2 expressions and the impairment of cytokine production.

Minocycline half-life is 16 hours (range: 11-23 hours).

• Minocycline (Dynacin) versus Other Medications

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• 3.Qadri SM, Halim M, Ueno Y, Saldin H. Susceptibility of methicillin-resistant Staphylococcus aureus to minocycline and other antimicrobials. Chemotherapy 1994;40:26-29
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• 6. Tikka T, Usenius T, Tenhunen M, Keinanen R, Koistinaho J. Abstract Tetracycline derivatives and ceftriaxone, a cephalosporin antibiotic, protect neurons against apoptosis induced by ionizing radiation. J Neurochem. 2001 Sep;78(6):1409-14. PubMed
• 7. Morimoto N, Shimazawa M, Yamashima T, Nagai H, Hara H. Abstract Minocycline inhibits oxidative stress and decreases in vitro and in vivo ischemic neuronal damage. Brain Res. 2005 May 17;1044(1):8-15. Epub 2005 Apr 13. PubMed
• 8. Yrjanheikki J, Tikka T, Keinanen R, Goldsteins G, Chan PH, Koistinaho J. Free in PMC A tetracycline derivative, minocycline, reduces inflammation and protects against focal cerebral ischemia with a wide therapeutic window. Proc Natl Acad Sci U S A. 1999 Nov 9;96(23):13496-500.
• 9. Fox C, Dingman A, Derugin N, Wendland MF, Manabat C, Ji S, Ferriero DM, Vexler ZS. Free in PMC Minocycline confers early but transient protection in the immature brain following focal cerebral ischemia-reperfusion. J Cereb Blood Flow Metab. 2005 Sep;25(9):1138-49. Erratum in: J Cereb Blood Flow Metab. 2006 Mar;26(3):446. PubMed
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• 12. Chen M, Ona VO, Li M, Ferrante RJ, Fink KB, Zhu S, Bian J, Guo L, Farrell LA, Hersch SM, Hobbs W, Vonsattel JP, Cha JH, Friedlander RM. Abstract Minocycline inhibits caspase-1 and caspase-3 expression and delays mortality in a transgenic mouse model of Huntington disease. Nat Med. 2000 Jul;6(7):797-801. PubMed
• 13. Zhu S, Stavrovskaya IG, Drozda M, Kim BY, Ona V, Li M, Sarang S, Liu AS, Hartley DM, Wu DC, Gullans S, Ferrante RJ, Przedborski S, Kristal BS, Friedlander RM. Abstract Minocycline inhibits cytochrome c release and delays progression of amyotrophic lateral sclerosis in mice. Nature. 2002 May 2;417(6884):74-8.
• 14. Amin AR, Attur MG, Thakker GD, Patel PD, Vyas PR, Patel RN, Patel IR, Abramson SB. Free in PMC A novel mechanism of action of tetracyclines: effects on nitric oxide synthases. Proc Natl Acad Sci U S A. 1996 Nov 26;93(24):14014-9.
• 15. Bastos LF, Merlo LA, Rocha LT, Coelho MM. Abstract Characterization of the antinociceptive and anti-inflammatory activities of doxycycline and minocycline in different experimental models. Eur J Pharmacol. 2007 Dec 8;576(1-3):171-9. Epub 2007 Jul 31. PubMed
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• 19. Muellegger RR, Zoechling N, Soyer HP, Hoedl S, Wienecke R, Volkenandt M, Kerl H. Abstract No detection of Borrelia burgdorferi-specific DNA in erythema migrans lesions after minocycline treatment. Arch Dermatol. 1995 Jun;131(6):678-82.
• 20. Tilley BC, Alarco'n GS, Heyse SP, Trentham DE, Neuner R, Kaplan DA, Clegg DO, Leisen JC, Buckley L, Cooper SM, Duncan H, Pillemer SR, Tuttleman M, Fowler SE. Free Full Text Minocycline in rheumatoid arthritis. A 48-week, double-blind, placebo-controlled trial. MIRA Trial Group. Ann Intern Med. 1995 Jan 15;122(2):81-9. PubMed
• 21. Williams S, Wakisaka A, Zeng QQ, Barnes J, Martin G, Wechter WJ, Liang CT. Minocycline prevents the decrease in bone mineral density and trabecular bone in ovariectomized aged rats. Bone. 1996 Dec;19(6):637-44. PubMed
• 22. Kurlandsky LE, Fader RC. In vitro activity of minocycline against respiratory pathogens from patients with cystic fibrosis. Pediatr Pulmonol. 2000 Mar;29(3):210-2.
• 23. Patterson PR. Minocycline in the antibiotic regimen of cystic fibrosis patients: weight gain and clinical improvement. Clin Pediatr (Phila). 1977 Jan;16(1):60-3. PubMed
• 24. Bachelez H, Senet P, Cadranel J, Kaoukhov A, Dubertret L. The use of tetracyclines for the treatment of sarcoidosis. Arch Dermatol. 2001 Jan;137(1):69-73.
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• 27. Saivin S, Houin G. Abstract Clinical pharmacokinetics of doxycycline and minocycline. Clin Pharmacokinet. 1988 Dec;15(6):355-66. Review. PubMed
• 28. Eady EA, Cove JH, Holland KT, Cunliffe WJ. Abstract Superior antibacterial action and reduced incidence of bacterial resistance in minocycline compared to tetracycline-treated acne patients. Br J Dermatol. 1990 Feb;122(2):233-44. PubMed
• 29. Kuck NA, Forbes M. Uptake of minocycline and tetracycline by tetracycline-susceptible and -resistant bacteria. Antimicrob Agents Chemother. 1973 Jun;3(6):662-4.
• 30. Sarma N, Malakar S, Lahiri K, Banerjee U. Serum sickness like reaction with minocycline. Indian J Dermatol Venereol Leprol. 2004 Jan-Feb;70(1):43-4. FullText
• 31. Chiu AM, Chuenkongkaew WL, Cornblath WT, Trobe JD, Digre KB, Dotan SA, Musson KH, Eggenberger ER. Minocycline treatment and pseudotumor cerebri syndrome. Am J Ophthalmol. 1998 Jul;126(1):116-21. PubMed
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• 34. Bowles WH, Baylor College of Dentistry, Texas A&M University System Protection against minocycline pigment formation by ascorbic acid, J Esthet Dent, 10(4):182-6 1998

Published: July 01, 2008
Last updated: January 07, 2010