These adverse effects are analogous to the symptoms of opioid withdrawal, as the μ-opioid receptor blockade will increase gastrointestinal motility. The side effects of naltrexone by incidence are as follows:
Greater than 10%: difficulty sleeping, anxiety, nervousness, abdominal pain/cramps, nausea and/or vomiting, low energy, joint/muscle pain, and headache. Less than 10%: loss of appetite, diarrhea, constipation, thirstiness, increased energy, feeling down, irritability, dizziness, skin rash, delayed ejaculation, erectile dysfunction, and chills. A variety of other adverse events have also been reported with less than 1% incidence. Opioid withdrawal
Naltrexone should not be started until several (typically 7–10) days of abstinence from opioids have been achieved. This is due to the risk of acute opioid withdrawal if naltrexone is taken, as naltrexone will displace most opioids from their receptors. The time of abstinence may be shorter than 7 days, depending on the half-life of the specific opioid taken. Some physicians use a naloxone challenge to determine whether an individual has any opioids remaining. The challenge involves giving a test dose of naloxone and monitoring for opioid withdrawal. If withdrawal occurs, naltrexone should not be started. Aversive effects
Whether naltrexone causes dysphoria, depression, anhedonia, or other aversive effects as side effects has been studied and reviewed. In early studies in normal and opioid-abstinent individuals, acute and short-term administration of naltrexone was reported to produce a variety of aversive effects including fatigue, loss of energy, sleepiness, mild dysphoria, depression, lightheadedness, faintness, mental confusion, nausea, gastrointestinal disturbances, sweating, and occasional feelings of unreality.
Periorbital dermatitis  is a skin condition, a variant of perioral dermatitis, occurring on the lower eyelids and skin adjacent to the upper and lower eyelids. See also
Granulomatous perioral dermatitis
Perioral dermatitis


== References ==