Naltrexone is a medication prescribed to treat Alcohol Use Disorder (AUD) and Opioid Use Disorder (OUD). It is available in an oral tablet form and an extended-release injectable suspension, which may be sold under the brand names ReVia, Depade, or Vivitrol. The drug functions as an opioid receptor antagonist, meaning it binds to opioid receptors in the brain and throughout the body without activating them. By occupying these receptors, Naltrexone effectively blocks the euphoric and rewarding effects that result from alcohol consumption or opioid use. This action helps diminish cravings and minimize the reinforcement of substance use.
Nausea as a Common Side Effect
Nausea is one of the most frequently reported side effects for patients taking oral Naltrexone. This gastrointestinal discomfort is especially common during the initial period of treatment as the body begins to adjust to the medication. Typically, the nausea is described as mild to moderate in severity, and it often occurs alongside other minor digestive issues like stomach pain or vomiting. Studies have indicated that moderate to severe nausea affects about 15% of patients in the first week of therapy.
This common side effect tends to follow a predictable timeline, often subsiding significantly after the first few days to one or two weeks of consistent use. The temporary nature of the nausea means that many patients find the discomfort manageable as their body acclimates to the daily dosing regimen. Research also suggests that younger patients and female patients may be more likely to report a higher rate of nausea when beginning Naltrexone. Persistent or severe nausea should prompt a discussion with a healthcare provider.
Biological Basis of Naltrexone-Induced Nausea
The gastrointestinal symptoms, including nausea, are a direct result of Naltrexone’s mechanism as an opioid receptor antagonist. Opioid receptors, particularly the mu-opioid receptor, are densely distributed throughout the gastrointestinal tract, not just the brain. These peripheral receptors normally help regulate functions like gut motility and secretion.
When Naltrexone is introduced, it blocks these peripheral opioid receptors, which can disrupt the natural, rhythmic movement of the digestive system. This alteration in gut function can manifest as feelings of sickness and discomfort, contributing to the experience of nausea. Additionally, the medication’s action extends to the central nervous system, where it may influence the Chemoreceptor Trigger Zone (CTZ). The CTZ is an area in the brainstem responsible for detecting circulating toxins and initiating the vomiting reflex. By interacting with opioid receptors in this area, Naltrexone can stimulate the CTZ, further inducing feelings of nausea.
Practical Steps for Minimizing Nausea
Patients can employ several practical strategies to minimize the likelihood and intensity of Naltrexone-induced nausea.
Taking Naltrexone With Food
Taking the oral tablet with food is a highly effective and frequently recommended method to reduce stomach upset. A small meal or snack provides a buffer that helps prevent the direct irritation of the stomach lining and slows the medication’s absorption.
Adjusting Dose Timing
Adjusting the timing of the dose can also be beneficial, especially if the nausea is accompanied by fatigue or dizziness. Some individuals find that taking their daily dose later in the evening or right before bed allows them to sleep through the peak period of potential side effects. This adjustment should only be made after consulting with the prescribing clinician to ensure it aligns with the overall treatment plan.
Dose Titration
Another strategy involves a gradual introduction of the medication, known as dose titration. A healthcare provider may start the patient on a lower dose, such as 25 milligrams (half the standard dose), for a few days before increasing to the full 50-milligram daily amount. This slower ramp-up allows the body more time to adapt to the presence of the opioid antagonist, which can lessen the initial shock to the system and mitigate the severity of the nausea.
Hydration and Warning Signs
Maintaining adequate hydration throughout the day is also important, as dehydration can often exacerbate feelings of sickness. For persistent but manageable nausea, some over-the-counter remedies, like ginger supplements or antacids, may offer relief, though any new medication should be discussed with a doctor. If the nausea becomes severe, does not improve after the first few weeks, or is accompanied by serious symptoms like yellowing of the skin or eyes, severe abdominal pain, or dark urine, the patient should stop the medication immediately and contact a healthcare professional, as these may signal a more serious issue.