Naltrexone Side Effects
Medically reviewed by Drugs.com. Last updated on Apr 16, 2022.
In Summary
Commonly reported side effects of naltrexone include: streptococcal pharyngitis, syncope, anxiety, arthralgia, arthritis, dizziness, drowsiness, fatigue, frequent headaches, headache, joint stiffness, nasopharyngitis, nausea, nervousness, obsessive compulsive disorder, panic attack, pharyngitis, posttraumatic stress disorder, sedated state, sinus headache, vomiting, induration at injection site, malaise, pain at injection site, and tenderness at injection site. Other side effects include: muscle cramps, muscle rigidity, muscle spasm, stiffness, depression, and twitching. See below for a comprehensive list of adverse effects.
For the Consumer
Applies to naltrexone: oral tablet
Other dosage forms:
Side effects requiring immediate medical attention
Along with its needed effects, naltrexone may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur while taking naltrexone:
Less common
Rare
- Abdominal or stomach pain (severe)
- blurred vision, aching, burning, or swollen eyes
- chest pain
- confusion
- discomfort while urinating or frequent urination
- fever
- hallucinations or seeing, hearing, or feeling things that are not there
- itching
- mental depression or other mood or mental changes
- ringing or buzzing in the ears
- shortness of breath
- swelling of the face, feet, or lower legs
- weight gain
Side effects not requiring immediate medical attention
Some side effects of naltrexone may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.
Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
More common
- Abdominal or stomach cramping or pain (mild or moderate)
- anxiety, nervousness, restlessness or trouble sleeping
- headache
- joint or muscle pain
- nausea or vomiting
- unusual tiredness
Less common
- Chills
- constipation
- cough, hoarseness, runny or stuffy nose, sinus problems, sneezing, or sore throat
- diarrhea
- dizziness
- fast or pounding heartbeat
- increased thirst
- irritability
- loss of appetite
- sexual problems in males
For Healthcare Professionals
Applies to naltrexone: compounding powder, intramuscular powder for injection extended release, oral tablet
Nervous system
Very common (10% or more): Headache (25%), dizziness/syncope (13%)
Common (1% to 10%): Somnolence/sedation
Frequency not reported: Lethargy, cerebral arterial aneurysm, convulsions, disturbance in attention, dysgeusia, mental impairment, migraine, ischemic stroke, paresthesia[Ref]
Psychiatric
Very common (10% or more): Insomnia/sleep disorder (14%), anxiety (12%)
Common (1% to 10%): Depression
Uncommon (0.1% to 1%): Suicide attempt/ideation
Frequency not reported: Irritability, abnormal dreams, agitation, alcohol withdrawal syndrome, euphoric mood, delirium, libido decreased[Ref]
Gastrointestinal
Very common (10% or more): Nausea (33%), vomiting NOS (14%), diarrhea (13%), abdominal pain (11%)
Common (1% to 10%): Dry mouth, toothache
Frequency not reported: Abdominal discomfort, colitis, constipation, flatulence, gastroesophageal reflux disease, gastrointestinal hemorrhage, hemorrhoids, pancreatitis acute, paralytic ileus[Ref]
Hepatic
Very common (10% or more): Alanine aminotransferase increased (13%), aspartate aminotransferase increased (10%)
Common (1% to 10%): Gamma-glutamyltransferase increased
Frequency not reported: Lymphadenopathy including cervical adenitis, white blood cell count increased, cholecystitis acute, cholelithiasis[Ref]
Local
Very common (10% or more): Injection site tenderness (45%), injection site induration (35%), injection site pain (17%), other injection site reaction (primarily nodules, swelling) (15%), injection site pruritus (10%)
Common (1% to 10%): Injection site ecchymosis[Ref]
Musculoskeletal
Very common (10% or more): Arthralgia/arthritis/joint stiffness (12%)
Common (1% to 10%): Back pain/stiffness, muscle cramps
Frequency not reported: Chills, joint stiffness, muscle spasms, myalgia, pain in limb[Ref]
Other
Very common (10% or more): Asthenic conditions (23%)
Frequency not reported: Chest pain, chest tightness, abortion missed[Ref]
Cardiovascular
Frequency not reported: Angina pectoris, angina unstable, atrial fibrillation, cardiac failure congestive, coronary artery atherosclerosis, myocardial infarction, palpitations, deep vein thrombosis[Ref]
Respiratory
Frequency not reported: Chronic obstructive pulmonary disease, dyspnea, pharyngolaryngeal pain, sinus congestion[Ref]
Dermatologic
Common (1% to 10%): Rash
Frequency not reported: Face edema, night sweats, pruritus, sweating increased[Ref]
Metabolic
Very common (10% or more): Anorexia/appetite decreased NOS/appetite disorder NOS (14%)
Frequency not reported: Weight decreased, weight increased, appetite increased, dehydration[Ref]
Renal
Very common (10% or more): Abnormal creatinine phosphokinase levels (17%)[Ref]
Hematologic
Frequency not reported: Eosinophil counts increased, decreased platelet count[Ref]
Ocular
Frequency not reported: Conjunctivitis, vision blurred[Ref]
Hypersensitivity
Frequency not reported: Hypersensitivity reaction (including angioneurotic edema and urticaria)
Postmarketing reports: Anaphylaxis[Ref]
Immunologic
Very common (10% or more): Pharyngitis (11%)
Common (1% to 10%): Nasopharyngitis
Frequency not reported: Seasonal allergies[Ref]
Frequently asked questions
- What happens if you drink alcohol while taking naltrexone?
- Can you drink alcohol on Vivitrol or will you get sick?
- Does naltrexone cause weight gain?
- What to avoid when taking naltrexone?
- Should I take naltrexone in the morning or at night?
- What's the difference between naltrexone and naloxone?
- How long does naltrexone take to work?
- How does naltrexone make you feel?
- How long does Vivitrol last in your system?
- What happens if you take opiates while on Vivitrol?
- Does this drug make you sleepy?
- Does this drug block endorphins?
- Is naltrexone a controlled substance?
- How and where is the Vivitrol injection given?
More about naltrexone
- Drug interactions
- Dosage information
- During pregnancy or Breastfeeding
- Reviews (522)
- Patient tips
- Drug images
- Compare alternatives
- Pricing & coupons
- Drug class: antidotes
Patient resources
- Drug Information
- Naltrexone injection
- Naltrexone (Advanced Reading)
- Naltrexone Intramuscular (Advanced Reading)
- Naltrexone Tablets
Professional resources
Related treatment guides
References
1. "Product Information. Vivitrol (naltrexone)." Alkermes, Inc, Cambridge, MA.
2. "Product Information. Naltrexone Hydrochloride (naltrexone)." Accord Biopharma Inc, Durham, NC.
Further information
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Some side effects may not be reported. You may report them to the FDA.