Effect of zinc sulphate on the absorption of tetracycline and doxycycline in man

Eur J Clin Pharmacol. 1975 Dec 19;9(2-3):131-4. doi: 10.1007/BF00614009.


A possible interaction between zinc sulphate and tetracycline or doxycycline was examined in a cross-over study in seven volunteers. A single dose of zinc sulphate (45 mg Zn++) was given simultaneously with tetracycline hydrochloride (500 mg) or doxycyline chloride (200 mg). The serum concentration of tetracycline, the area under the serum tetracycline concentration-time curve and the excretion of tetracycline in urine were reduced by about 30% (p less than 0.05) from the respective control values. The absorption of doxycycline was not influenced significantly by zinc sulphate. The clinical significance of the zinc-tetracycline interaction seems to be of limited importance.

Publication types

  • Clinical Trial
  • Comparative Study
  • Controlled Clinical Trial

MeSH terms

  • Adult
  • Aged
  • Clinical Trials as Topic
  • Doxycycline / metabolism*
  • Drug Interactions
  • Humans
  • Intestinal Absorption / drug effects
  • Middle Aged
  • Tetracycline / metabolism*
  • Zinc / pharmacology*


  • Tetracycline
  • Zinc
  • Doxycycline