Naltrexone is a medication approved for the treatment of Opioid Use Disorder (OUD) and Alcohol Use Disorder (AUD). It works by blocking opioid receptors in the brain, which helps to reduce cravings and prevent the euphoric effects of opioids and alcohol. Individuals starting this treatment often wonder if the initial side effects will eventually subside. The body typically adjusts to the medication over time, leading to a significant reduction in initial adverse reactions.
Common Physical Reactions to Naltrexone
The initial days of taking Naltrexone can involve mild-to-moderate physical reactions as the body adjusts. Frequently reported side effects include nausea, often accompanied by gastrointestinal issues like abdominal cramping or diarrhea. These digestive disturbances are temporary and typically manageable.
Headaches are also common, along with feelings of dizziness or lightheadedness. Patients may also notice sleep disturbances, such as insomnia or increased sleepiness and fatigue. These reactions indicate the body is adapting to the medication and its mechanism of action on the central nervous system.
The Typical Timeline for Side Effect Resolution
For most people, the initial side effects of Naltrexone are temporary and resolve quickly with consistent use. These effects typically peak within the first few days as the drug concentration builds up in the body. Most patients report that side effects significantly lessen or disappear entirely within the first one to two weeks of daily dosing.
This resolution is largely due to the body reaching a pharmacokinetic steady-state, meaning the amount of drug entering the body is balanced with the amount being cleared. Once this balance is achieved, the body’s initial reaction tends to diminish. While some people may experience minor side effects for a longer period, the intense discomfort rarely persists beyond this initial adjustment period.
The standard oral dose of Naltrexone is typically 50 milligrams per day, and the initial reaction is often a response to this sudden introduction. The quick resolution of symptoms for most people is a positive sign that the body is adapting to the therapeutic drug level.
Practical Steps for Symptom Management
While waiting for the body to fully adjust, there are several practical steps that can be taken to mitigate the temporary side effects. Taking the oral tablet with food or a snack is an effective strategy for reducing nausea and digestive upset. Avoiding taking the medication on an empty stomach can substantially lessen the irritation to the gastrointestinal tract.
Adjusting the timing of the dose helps manage side effects like fatigue or dizziness. Taking the medication at night allows a person to sleep through the peak of sedating or disorienting effects. For headaches, over-the-counter pain relievers (e.g., acetaminophen or ibuprofen) can be helpful, but their use should be discussed with a physician first.
Some providers recommend starting with a lower dose (e.g., 25 milligrams) and gradually increasing to the full 50-milligram dose over several days for a smoother transition. Staying well-hydrated throughout the day by drinking plenty of water can also help alleviate headaches and reduce the severity of gastrointestinal symptoms. These temporary coping mechanisms can make the initial adjustment period much more tolerable.
Identifying Serious or Persistent Reactions
While most initial reactions are mild and resolve quickly, serious or persistent reactions require immediate medical consultation. Naltrexone can affect the liver in rare cases, so signs of liver injury must be reported immediately. Symptoms include yellowing of the skin or eyes (jaundice), dark urine, light-colored or clay-colored stools, and persistent pain in the upper right side of the abdomen.
Changes in mental health are a serious concern; any new or worsening depression, severe mood changes, or thoughts of self-harm warrant immediate medical intervention. If common side effects, such as nausea or headache, are debilitating or persist beyond the typical two-week adjustment period, discuss this with the prescribing physician. These persistent symptoms may indicate a need to adjust the dosage or explore alternative treatment options.