Patients taking doxercalciferol may experience the common side effects of this drug. These side effects often alleviate over time, but if they persist or worsen the patient should consult their physician. The common side effects include fatigue, headache, vomiting, upset stomach, nausea, and constipation. Serious side effects are not likely, but if they do occur the patient should consult their physician immediately. The serious side effects include unexplained weight loss or gain, joint/bone/muscle pain, weakness, loss of appetite, metallic taste in mouth, increased thirst, mood/mental changes, significant drowsiness, increased thirst, slow/fast/irregular heartbeat, and increased urination. On rare occasions, a patient may experience an allergic reaction to this medication. If this occurs, the patient should seek immediate medical attention. Allergic reaction signs include rash, difficulty breathing, swelling (particularly the face, lips, eyelids), itching, and extreme dizziness.