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

Abstract

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.

Pengaruh Alfa Tokoferol pada Efek Ototoksik Sisplatin

“…Antibiotik golongan kuinolon dan tetrasiklin menghambat penyerapan seng dalam saluran cerna. 8,9 Pada anak Banglades berstatus gizi baik dengan infeksi saluran napas bawah akut, kadar seng plasma dan rambut signifikan lebih rendah. 10 Di India Utara anak yang dirawat karena pneumonia berat, memiliki kadar seng plasma lebih rendah dibandingkan dengan kontrol.…”

Metal ion-tetracycline interactions in biological fluids. Part 5. Formation of zinc complexes with tetracycline and some of its derivatives and assessment of their biological significance

“…Tetracyclines have their optimum solubility at low pH values and the effects of the antacids may logically be attributed to the reduced dissolution correlated to the raising of the gastric pH [29]. Besides, complexation of the ,drug with metal ions was also shown to be directly responsible for its reduced absorption [31,[48][49][50], the more so as (i) the effects were observed to be dependent on the nature of the anion of the metal salt [30,40,51], (ii) the absorption of the metal itself was proved to be simultaneously affected [34,48].…”

“…The gastrointestinal absorption of tetracycline and its derivatives is known to be impaired by the simultaneous ingestion of food and antacids containing various metal ions [30,31]. Tetracyclines have their optimum solubility at low pH values and the effects of the antacids may logically be attributed to the reduced dissolution correlated to the raising of the gastric pH [29].…”

“…Many reports are available in the literature which refer to the high affinity of these substances for transition metal ions [22][23][24][25][26][27][28]. In this respect, several clinical investigations were devoted to the potential influence of zinc on the gastrointestinal absorption of tetracyclines [29][30][31]. Zinc was shown to exert an important antagonism against the absorption of tetracycline itself [29][30][31], but this effect proved less signifi-cant for doxycycline [31].…”

“…In this respect, several clinical investigations were devoted to the potential influence of zinc on the gastrointestinal absorption of tetracyclines [29][30][31]. Zinc was shown to exert an important antagonism against the absorption of tetracycline itself [29][30][31], but this effect proved less signifi-cant for doxycycline [31]. Tetracycline absorption being a passive diffusion phenomenon [32], the possible formation of electrically charged complexes of zinc may indeed reduce the proportion of the lipophilic forms of the antibiotic.…”