Here are the possible side effects of Xanax:

• Side effects of Xanax may include:
  Decreased libido, drowsiness, fatigue, impaired coordination, memory impairment, speech difficulties, weight changes

• Side effects of Xanax XR may include:
  Constipation, decreased libido, depression, drowsiness, fatigue, impaired coordination, memory problems, mental impairment, nausea, sedation, sleepiness, speech difficulties, weight changes

• Side effects due to a rapid decrease in dose or abrupt withdrawal from Xanax or Xanax XR:
  Anxiety, blurred vision, decreased concentration, decreased mental clarity, depression, diarrhea, headache, heightened awareness of noise or bright lights, hot flushes, impaired sense of smell, insomnia, loss of appetite, loss of reality, muscle cramps, nervousness, rapid breathing, seizures, tingling sensation, tremor, twitching, weight loss