| Indication | For the treatment of infections caused by susceptible strains of microorganisms, such as Rocky Mountain spotted fever, typhus fever and the typhus group, Q fever, rickettsial pox and tick fevers caused by Rickettsiae, upper respiratory tract infections caused by Streptococcus pneumoniae and for the treatment of asymptomatic carriers of Neisseria meningitidis. |
| Pharmacodynamics | Minocycline, the most lipid soluble and most active tetracycline antibiotic, is, like doxycycline, a long-acting tetracycline. Minocycline's effects are related to the inhibition of protein synthesis. Although minocycline's broader spectrum of activity, compared to other members of the group, includes activity against Neisseria meningitidis, its use as a prophylaxis is no longer recomended because of side effects (dizziness and vertigo). Current research is examining the possible neuroprotective effects of minocycline against progression of Huntington's Disease, an inherited neurodegenerative disorder. The neuroprotective action of minocycline may include its inhibitory effect on 5-lipoxygenase, an inflammatory enzyme associated with brain aging. |
| Mechanism of action | Minocycline passes directly through the lipid bilayer or passively diffuses through porin channels in the bacterial membrane. Tetracyclines like minocycline bind to the 30S ribosomal subunit, preventing the binding of tRNA to the mRNA-ribosome complex and interfering with protein synthesis. |
| Absorption | Rapidly absorbed from the gastrointestinal tract and absorption is not significantly impaired by ingestion of food or milk. Oral bioavailability is 100%. |
| Volume of distribution | Not Available |
| Protein binding | 55% to 76% |
| Metabolism | Hepatic. |
| Route of elimination | Not Available |
| Half life | 11-22 hours |
| Clearance | Not Available |
| Toxicity | Minocycline has been observed to cause a dark discoloration of the thyroid in experimental animals (rats, minipigs, dogs and monkeys). In the rat, chronic treatment with minocycline has resulted in goiter accompanied by elevated radioactive iodine uptake and evidence of thyroid tumor production. Minocycline has also been found to produce thyroid hyperplasia in rats and dogs. LD50=2380 mg/kg (rat, oral), LD50=3600 mg/kg (mouse, oral) |