Zinc oxide is a mineral used in many creams and ointments to prevent or treat sunburn and other skin irritations like diaper rash. It's also available in oral formulations to promote wound healing. Although zinc oxide is generally considered safe in small amounts, some side effects can occur, particularly if you exceed the maximum recommended dose.
In rare instances, topical forms of zinc oxide may produce an allergic reaction on skin, including burning, stinging, itching, tingling and dark discoloration, according to the National Institutes of Health. An allergy to the oral form of the drug can lead to hives, difficulty breathing and swelling. Many zinc topical preparations also include additional ingredients, so if you are allergic to commonly used additives such as dimethicone, lanolin, cod liver oil, petroleum jelly, parabens, mineral oil or wax, you should probably avoid using these products, cautions Drugs.com.
Drug interactions are found most often with oral zinc oxide. Avoid taking this supplement if you're also on cisplatin for chemotherapy, since a high intake of zinc may help cancer cells become resistant to that drug. With other medicines like penicillamine, tetracyclines and fluoroquinolones, zinc oxide can prevent them from being absorbed into the bloodstream, so you should avoid taking them two hours before or four to six hours after zinc, according to Dr. Arthur Schoenstadt of eMedTV.com.
Metal Fume Fever
Inhalation of large amounts of zinc oxide fumes can cause a condition called metal fume fever. The Linus Pauling Institute reports that symptoms of this fever, including profuse sweating, weakness and rapid breathing, usually develop with eight hours of inhalation and persist for up to 24 hours after exposure.
The recommended dietary allowance for zinc supplements for pregnant women is 11 mg daily, with the maximum safe amount 40 mg daily. However, topical zinc oxide is on the Food and Drug Administration's pregnancy category C list, meaning that it may be harmful to an unborn baby or if it's passed through breast milk. You should tell your doctor if you are pregnant or nursing and taking zinc oxide, suggests Drugs.com.
Taking too many zinc oxide supplements can be toxic to your body. Symptoms of zinc toxicity may include watery diarrhea, kidney problems, lethargy, chills and fever, yellowing of the whites of your eyes or skin, coughing and mouth and throat irritation. The University of Maryland Health Center adds that if you ingest a zinc oxide topical cream or ointment, it can lead to an overdose, causing gastrointestinal problems like stomach pain, nausea, vomiting and diarrhea.