Low
Good (70 to 90%)
Use during last half of pregnancy, infancy or in children < 8 years can cause permanent yellow discolouration of the teeth.
Toxic to human embryos (impaired skeletal development, mental retardation)
Tetracyclines have an anti-anabolic effect that can manifest as an increase in BUN. This can aggravate azotemia, raise serum phosphorus levels and worsen acidosis.
Drug accumulation can be toxic to the liver.
Photosensitivity
Tetracycline increases levels of warfarin, digoxin.
Major substrate of CYP3A4 - levels affected by co-administration with inducers and inhibitors of CYP3A4.
Derivatives of tetracycline such as doxycycline and minocycline are more active with convenient dosing and therefore are used more often.
Pharmacology: Inhibits bacterial protein synthesis by binding with the 30S and possibly the 50S ribosomal subunit(s) of susceptible bacteria.
Antimicrobial class: Tetracyclines
Pregnancy category: D
Average serum half life: 6 - 11 hours
Biliary penetration: 200 - 3200 % of plasma concentration
CSF penetration: Poor
Metabolism: Majority not metabolised and excreted in urine and faeces.
Route of Elimination:
Renal: 30%
GI: 20 - 60%
