For many people with alcohol or opioid use disorder, Vivitrol is a very important part of their treatment plan. But, like any medication, it can cause side effects. And though most of these side effects are mild and temporary, especially after an injection, some reactions require medical attention.
Knowing what to expect can make it easier to recognize what is normal after your Vivitrol shot and what warrants a call to your healthcare provider.
How Common Are Vivitrol Side Effects?
There is no guarantee that you will have some type of reaction when you receive your monthly Vivitrol shot, but for many people, symptoms that do appear tend to lessen after the first couple of doses.[1]
Because Vivitrol is administered as a monthly shot instead of a daily pill, most of the reactions will occur due to receiving the shot or from the body getting used to taking the medicine. Knowing the most common side effects of Vivitrol can help alleviate anxiety and prepare you for what to expect after your injection.
The vast majority of the side effects listed below are normal side effects associated with starting this type of treatment, and most will resolve themselves in a short time frame.[2]
Common side effects include:
- Injection-site pain, tenderness, swelling, or a lump
- Nausea
- Headache
- Fatigue
- Dizziness
- Sleepiness or difficulty sleeping
- Muscle cramps or joint pain
- Reduced appetite
- Cold-like symptoms
| Side Effect | How Common | Usually Temporary? |
| Injection-site soreness | Very common | Yes |
| Nausea | Common | Usually |
| Headache | Common | Usually |
| Fatigue | Common | Usually |
| Joint pain | Less common | Usually |
People often wonder how Vivitrol makes them feel overall, and the honest answer is that it varies from person to person. Some notice very little beyond mild soreness, while others feel tired or a bit off for a day or two after each injection.
Vivitrol’s Side Effect Duration
How long side effects last varies based on:
- The individual person’s metabolism
- If it’s your first dose; some side effects such as nausea are more noticeable after the initial dose
- Overall health
- Medications you are currently taking; Vivitrol may interact with other medications
- Stage of recovery from opioid or alcohol abuse
Standard Timeline
| Timeframe | What to expect |
| First 24–72 hrs (or 1–3 days) after receiving Vivitrol injection | Soreness at the injection site, general fatigue, nausea, headaches |
| 1st week after injection | The soreness at the injection site will slowly improve; appetite and energy levels will begin to increase |
| 2+ weeks after injection | For many, the majority of the milder side effects should be gone |
When these side effects remain for extended periods of time beyond what has been described above, such as when there is a lump at the injection site which does not shrink, persistent nausea, and depression or mood swings that continue until the next scheduled Vivitrol shot, they may be worthy of bringing to a healthcare professional.
Severe Vivitrol Reactions and Emergency Care
While severe side effects from Vivitrol are unusual, you should know what they look like. By knowing whether your reaction is mild or serious, you can get immediate help when needed.
While mild soreness is common, severe injection site reactions such as significant swelling, skin discoloration, tissue damage, or unusual bleeding problems at the injection site require prompt medical evaluation. The discomfort many have after receiving an injection is very different. A severe reaction needs to be evaluated by a doctor; do not treat it yourself.
There is a small chance that some people could develop liver dysfunction. If one experiences a sudden appearance of jaundice (yellowing of the skin and eyes), a darker-than-usual urine, aching abdominal pain, persistent nausea, or extreme fatigue, it would be wise to seek immediate attention. Those with pre-existing liver conditions, such as hepatitis, should consult with their physician prior to beginning treatment because naltrexone can affect the liver and has been associated with hepatitis and liver dysfunction.[3]
Those experiencing allergic reactions such as swelling, rash, or difficulty breathing should seek emergency assistance immediately instead of waiting and seeing what happens.
Depression or suicidal thoughts are a possible side effect of Vivitrol.[4] This does not happen to everyone, and having these thoughts does not mean something has gone permanently wrong, but it is essential to note that if you notice any differences in your mood, you should share this information with your health care provider to monitor and address these mood swings.
Sudden opioid withdrawal symptoms may also occur in those receiving Vivitrol if there are still opioids in their system at the time of administration.[5] Since Vivitrol is the brand name for the extended-release form of naltrexone, the active ingredient works on opioid receptors, blocking the effects of opioids. Because of this, people should complete an appropriate detox period and be free of opioids before receiving Vivitrol to reduce the risk of precipitated withdrawal.
Are Side Effects More Common After the First Dose of Vivitrol?
Yes.
It can be expected that the initial dose will cause more side effects than future doses.[6] This is because your body is experiencing the medication for the first time. As such, there are usually the greatest amounts of pain and minor side effects after the first dose.
However, once you begin to develop familiarity with both the medication and the administration process, the number of side effects typically reduces with each subsequent dose. This is based on individual experiences, and many patients do not feel a difference from one dose to another.
Is Vivitrol a Safe Option for Treatment Over Time?
For many people, yes.
Vivitrol treatment can be continued long-term when a healthcare provider regularly evaluates progress and monitors for side effects. While it is impossible to provide guarantees of safety over prolonged periods, research conducted by the National Institute on Drug Abuse, along with FDA-approved information, indicates that the extended-release formulation of naltrexone (Vivitrol) generally provides long-term tolerance when appropriately monitored.[7]
Healthcare professionals regularly assess the need for continued treatment by reviewing ongoing clinical data; they do not simply assume that Vivitrol will continue to be safe without routine follow-up visits.
However, any of the following factors might increase your risk of developing side effects:
- Liver problems
- Kidney problems
- Recent opioid use, including treatment with methadone
- Other medications being taken
- Allergies
- Pregnancy or breastfeeding
- Blood disorders such as hemophilia
You don’t have to exclude yourself from treatment because of any of the above. However, your doctor will probably want to keep an eye on how you’re doing. Having your complete health history when you come in for your first shot is the best way for your doctor to anticipate what might happen, rather than waiting until something does.
Tips for Managing Mild Vivitrol Side Effects
The following tips can make your next Vivitrol shot smoother and reduce the risk of pain and side effects:
- Drink plenty of water
- If you are prone to nausea, eat a small, easy-to-digest meal before your shot
- If you are tired, rest for a while
- Gently move around to ease muscle pain
- Don’t rub or irritate the injection area
- Follow through on your follow-up appointments
Remember these tips are to help with mild and normal side effects. Do not try to treat severe side effects by yourself. If you experience any side effect that gets severe enough, contact your doctor. Maintaining a simple symptom diary for each shot will allow your doctor to track any patterns in your side effects and make adjustments as necessary.
When Should Someone Call Their Healthcare Provider?
Call promptly if:
- Side effects worsen instead of improving
- A fever develops
- The injection site becomes increasingly painful
- Frequent vomiting
- Mood changes
- Skin or eyes turn yellow
Seek emergency care if:
- You have difficulty breathing
- You have a severe allergic reaction
- Chest pain develops
- Signs of opioid overdose appear
- Withdrawal symptoms become severe
Treatment for Alcohol and Opioid Use
There can be many questions and concerns regarding side effects from beginning an entirely new medication. Most side effects associated with Vivitrol are minimal, short-term, and easily managed by taking proper care. Serious reactions are extremely rare, though possible, and your health care team will help you track your progress and intervene if they notice something unusual.
Vivitrol typically works well as one component of a comprehensive treatment plan for substance use disorders, alongside counseling, behavioral therapy, peer support, and ongoing medical care. If at any time during your treatment you experience a concern over any side effect, it would be wise to speak directly with your healthcare professional prior to discontinuing the treatment.
Recovery is generally never a straight shot — and asking questions along the way is typical in the process. If you are struggling with alcohol or opioids and think Vivitrol, along with other addiction treatment, can make a meaningful difference, Freedom Center is here to help.
Reach out today. Our admissions team is here to answer your questions, verify your insurance, and help you see what treatment could look like for you.
