## **Core Concept**
Naltrexone is an opioid receptor antagonist used in the management of opioid addiction. It works by blocking the opioid receptors in the brain, thereby preventing the euphoric effects of opioids. This mechanism is crucial for its role in treating opioid dependence.

## **Why the Correct Answer is Right**
Naltrexone is specifically used for **maintenance therapy** in opioid addiction. By blocking opioid receptors, it helps in reducing cravings and preventing relapse in individuals who have been detoxified from opioids. This action is beneficial in the long-term management of opioid dependence, making it an effective tool for patients who are motivated to stay off opioids.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Naltrexone is not primarily used for acute detoxification. Acute detoxification usually involves medications that help manage withdrawal symptoms, such as methadone or buprenorphine, not an opioid antagonist like naltrexone.
- **Option B:** Naltrexone does not induce opioid withdrawal; rather, it prevents the effects of opioids. Medications like naloxone or clonidine might be used to manage withdrawal symptoms.
- **Option C:** While naltrexone can be used in the treatment of alcohol dependence, its primary indication related to the question context is opioid addiction.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that naltrexone should only be started after the patient has been opioid-free for a certain period (usually 7-10 days) to prevent precipitating withdrawal. This timing is crucial for its safe and effective use.

## **Correct Answer:** D. Maintenance therapy.