Severe Allergic Reactions

• According to Drugs.com, rashes, hives and other severe allergic reactions were observed in some oxytetracycline patients. Itching, chest tightness and breathing difficulties also have occurred.
  
  

Swelling

• According to Drugs.com, some people complained of swelling of the tongue, lips and mouth. Facial swelling, eye swelling and eye redness have been reported.
  
  

Gastrointestinal Effects

• According to Rxlist.com, nausea and vomiting were reported in some cases. Some people experienced diarrhea, anorexia and other gastrointestinal side effects.
  
  

Other Effects

• According to Rxlist.com, some patients have experienced unusual photosensitivity when exposed to sunlight or renal toxicity. A discoloration of the thyroid glands was observed in some cases.
  
  

Precautions

• According to Rxlist.com, a permanent discoloration of the teeth may occur among children under the age of 8 years. This drug can be passed on to unborn babies when it is taken by pregnant women.