Postmenopausal women treated with conjugated estrogens and
medroxyprogesterone acetate experienced reductions in zinc excretion of 35%
after 3 months and 26% after one year (Herzberg et al. 1996). The reduction was
more pronounced in women with osteoporosis who had elevated zinc excretion at
the beginning of the study. The clinical significance of this interaction is
There is a case report of a 58-year-old woman who developed a lupus
erythematosus-like syndrome within 1 week following the addition of zinc
sulphate therapy (200 mg po tid) to her drug regimen (30 to 200 mg/day
hydralazine; 120 to 640 mg/day propranolol; polythiazide; potassium chloride;
propylthiouracil; and thyroxine) for the treatment of leg ulcers (Fjellner
1979). Her symptoms included fever, abdominal distress, facial butterfly rash,
enlargement of the leg ulcers, oral ulcers, and maculopapular eruptions on legs,
trunk, and arms. Withdrawal of zinc prompted clinical improvement, including
healing of the oral ulcers and remission of the fever and abdominal distress.
However, the patient's condition did not resolve completely until all the
medications except thyroxine also were discontinued.
Anti-inflammatory Drugs (NSAIDs)
Zinc interacts with anti-inflammatory medications by forming complexes with
these drugs (Dendrinou-Samara et al. 1998).
Quinolone antibiotics form chelates with metal cations, such as aluminum,
magnesium, calcium, iron, zinc, copper, and manganese (Kara et al. 1991; Li et
al. 1999), which significantly reduces the absorption of these medications
(Balfour and Wiseman 1999; Brouwers 1992; Campbell and Hasinoff 1991). Dietary
supplements and antacids containing aluminum and magnesium should be taken two
to four hours before or after administration of these antibiotics (Hines Burnham
et al. 2000; Li et al.
Tetracyclines form chelates with divalent and trivalent cations, including
iron, aluminum, magnesium, and calcium (Neuvonen 1976). These chelates are
poorly soluble and can significantly reduce the absorption and efficacy of
tetracyclines (Hines Burnham et al. 2000; Neuvonen 1976). However, in an in
vitro study, zinc-drug interactions in gastrointestinal fluid influenced the
bioavailability of both zinc and tetracycline or tetracycline analogs (Brion et
Balfour JA, Wiseman LR. Moxifloxacin. Drugs. 1999;57(3):363-374.
Brion M, Lambs L, Berthon G. 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.
Agents Actions. 1985;17:230-242.
Brouwers JR. Drug interactions with quinolone antibacterials. Drug
Campbell NR, Hasinoff BB. Iron supplements: a common cause of drug
interactions. Br J Clin Pharmacol. 1991;31(3):251-255.
Dendrinou-Samara C, Tsotsou G, Ekateriniadou E, et al. Anti-inflammatory
drugs interacting with Zn(II), Cd(II) and Pt(II) metal ions. J Inorg Biochem.
1998; 71: 171-179.
Fjellner B. Drug-induced lupus erythematosus aggravated by oral zinc therapy.
Acta Dermatovener. 1979;59:368-370.
Herzberg M, Lusky A, Blonder J, Frenkel Y. The effect of estrogen replacement
therapy on zinc in serum and urine. Obstet Gynecol.
Hines Burnham, et al, eds. Drug Facts and Comparisons. St. Louis,
MO:Facts and Comparisons; 2000:1295.
Kara M, Hasinoff BB, McKay DW, et al. Clinical and chemical interactions
between iron preparations and ciprofloxacin. Br J Clin Pharmacol.
Li RC, Lo KN, Lam JS, et al. Effects of order of magnesium exposure on the
postantibiotic effect and bactericidal activity of ciprofloxacin. J
Neuvonen PJ. Interactions with the absorption of tetracyclines. Drugs.
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