Safety and side effects

Oral zinc can cause:

  • Indigestion
  • Diarrhea
  • Headache
  • Nausea
  • Vomiting

When oral zinc is taken long term and in high doses it can cause copper deficiency. People with low copper levels might experience neurological issues, such as numbness and weakness in the arms and legs.

The National Institutes of Health considers 40 mg of zinc a day to be the upper limit dose for adults and 4 mg of zinc a day for infants under age 6 months.

Don't use intranasal zinc. This form of zinc has been linked with the loss of the sense of smell.

Interactions

Possible interactions include:

  • Antibiotics. Using oral zinc while you're taking quinolone or tetracycline antibiotics can interfere with their ability to fight bacteria. Taking the antibiotic two hours before or four to six hours after taking zinc can minimize this effect.
  • Penicillamine. Using oral zinc with the rheumatoid arthritis drug penicillamine (Cuprimine, Depen) can reduce the drug's ability to ease arthritis symptoms. Taking zinc at least two hours before or after taking the drug might minimize this effect.
  • Thiazide diuretics. These blood pressure drugs increase the amount of zinc lost in urine.
Oct. 24, 2017