Nalmefene: Definition, Mechanism of Action, Uses, Dosage, Side Effects, Alternatives

Nalmefene, an opioid antagonist available as oral tablets and a nasal spray, treats alcohol use disorder and prevents opioid overdose by blocking opioid receptors, reducing alcohol cravings, and reversing respiratory depression. With 14.4% of New Jersey adults binge drinking monthly, Nalmefene serves a critical need.

In 2022, 31,807 individuals were admitted for alcohol addiction treatment in New Jersey, where medication-assisted treatment like nalmefene (18 mg orally once daily) could help those with continued cravings. Alcohol addiction causes 3,008 deaths annually in New Jersey.

Nalmefene’s side effects include nausea, dizziness, and headache, with serious effects like seizures requiring immediate medical attention. Alternatives include naltrexone, acamprosate, and disulfiram.

What Is Nalmefene?

Nalmefene is an opioid antagonist used in the treatment of addiction, specifically to reduce alcohol consumption in adults with alcohol use disorder (AUD) and to treat and prevent opioid overdose. In the U.S., it is known by the brand name Opvee, among other brand names like Revex and Selincro. It works by acting as an antagonist at the mu (μ)-opioid and delta (δ)-opioid receptors, and as a partial agonist at the kappa (κ)-opioid receptor, which helps manage the effects of opioids and reduce alcohol dependence. Nalmefene is available in various formulations, including oral tablets and nasal spray, and is crucial for emergency treatment of opioid overdose.

Is Nalmefene FDA-approved for Alcohol Dependence?

Nalmefene is not FDA-approved for alcohol dependence. It is a prescription medication used in alcohol addiction treatment in some countries, helping individuals reduce their alcohol consumption by targeting the brain’s reward system. As an opioid receptor antagonist, it works to decrease cravings and the pleasurable effects associated with alcohol use. However, the lack of FDA approval means that Nalmefene is not available for this purpose in the United States. Instead, other medications like naltrexone and acamprosate are commonly prescribed for alcohol addiction treatment within the U.S. healthcare system.

According to Paille, F.’s 2014 study, ‘Nalmefene: a new approach to the treatment of alcohol dependence’, nalmefene effectively reduces alcohol consumption in dependent patients. European approval was based on ESENSE 1 and 2 studies involving over 1,300 participants. These trials showed that nalmefene reduced heavy drinking days by approximately 2 days per month and decreased daily alcohol consumption by 5-11 grams compared to placebo. The medication works best for individuals with high drinking risk levels (consuming over 60g/day for men, and over 40g/day for women), where it cuts consumption by 14.3g/day. Responder analysis revealed patients taking nalmefene were more likely to achieve substantial results—25% achieved at least 70% reduction in total alcohol consumption, and 22% reduced their monthly heavy drinking days to four or fewer. Nalmefene uses a distinctive “as-needed” 18mg dosing approach taken when patients anticipate drinking risk. The European Medicines Agency approved this treatment specifically for reducing alcohol consumption rather than maintaining abstinence, and requires concurrent psychosocial support through the BRENDA program (Biopsychosocial evaluation, Report findings, Empathy, Needs identification, Direct advice, Assessment reaction).

What is the Mechanism of Action of Nalmefene?

The mechanism of action of nalmefene involves blocking opioid receptors (mu, delta, and kappa) in the brain to reduce the reward response associated with alcohol consumption. As an opioid receptor antagonist, nalmefene binds to these receptors, preventing endogenous opioids (e.g., endorphins) from activating them. 

This inhibition disrupts the release of dopamine, a neurotransmitter linked to pleasure and reinforcement, thereby diminishing the euphoric effects of alcohol. By modulating neurotransmitter activity, nalmefene reduces cravings and the compulsive drive to drink, as the brain’s reward system becomes less responsive to alcohol’s effects. This process helps individuals decrease alcohol intake by altering the neurochemical pathways that sustain addictive behavior.

What Are the Uses of Nalmefene?

The uses of Nalmefene are in the treatment of alcohol addiction and for managing opioid overdose. It functions by modulating opioid receptors in the brain to reduce cravings and the rewarding effects of alcohol, while also reversing opioid-induced respiratory depression in overdose cases.

The uses of Nalmefene are as below:

• Alcohol dependence: Reduces alcohol consumption in individuals with moderate to severe alcohol use disorder (AUD) who are not seeking complete abstinence. 

According to van den Brink, W.’s 2013 study, ‘Efficacy of as-needed nalmefene in alcohol-dependent patients with at least a high drinking risk level: results from a subgroup analysis of two randomized controlled 6-month studies’, nalmefene decreased heavy drinking days by 3.2 days per month and reduced total alcohol consumption by 14.3 grams per day compared to placebo after 6 months. Patients also experienced improved clinical status and liver function. The treatment works particularly well for high-risk drinkers (men consuming >60g/day, women >40g/day).

• Opioid overdose: Administered to reverse life-threatening respiratory depression caused by opioid overdose, including synthetic opioids. According to Wang, D. S.’s 1998 study, ‘Nalmefene: A Long-Acting Opioid Antagonist. Clinical Applications In Emergency Medicine, Nalmefene effectively treats opioid overdose with complete responses in 75% of confirmed cases. It prevents respiratory depression for 8 hours with an 11-hour half-life, compared to naloxone’s 1-1.5 hour duration. The recommended dose is 1-2 mg intravenously. No patients experienced recurrent intoxication after 4 hours. Side effects include vomiting, diarrhea, dizziness, tremulousness, and rarely pulmonary edema.

What is the Recommended Dosage of Nalmefene?

The recommended dose of nalmefene for alcohol dependence is 18 mg taken orally as needed, and administered once daily on days when the patient perceives a risk of alcohol consumption. This dose is recommended to be taken 1–2 hours before anticipated alcohol intake to maximize its effect on reducing cravings and the rewarding effects of alcohol.

Factors affecting dosage adjustments include the risk level of the patient, with nalmefene prescribed only to patients who continue to have a high drinking risk level (DRL) two weeks after initial assessment. According to Miyata, H.’s 2019 study, ‘Nalmefene in alcohol‐dependent patients with a high drinking risk: Randomized controlled trial’, Body size plays a significant role, with researchers including a 10 mg dose arm specifically because of the smaller stature of Japanese patients. Both 10 mg and 20 mg doses showed similar efficacy: 10 mg reduced heavy drinking days by 4.18 days/month, while 20 mg reduced them by 4.34 days/month compared to placebo. Adverse events showed dose dependency, occurring in 87.9% of patients on 20 mg versus 84.8% on 10 mg.

How Is Nalmefene Taken?

Nalmefene is taken as oral tablets, injections, nasal sprays, or monthly injections, depending on the treatment need. These various administration methods support alcohol dependence treatment and opioid overdose management across different clinical scenarios.

Here are the key ways Nalmefene is taken:

• Oral tablets: Taken by mouth, typically as an 18 mg dose, to reduce alcohol cravings and prevent relapse.
• Injections: Administered intravenously (IV), intramuscularly (IM), or subcutaneously (SC) by healthcare professionals, in emergency or clinical settings for opioid overdose reversal.
• Nasal spray: An over-the-counter formulation sprayed into the nostrils for rapid opioid overdose reversal, similar to naloxone.
• Monthly injections: A long-acting injectable form given every 3 months for sustained treatment, administered by a healthcare provider.

What Should You Do If You Miss a Dose of Nalmefene?

If you miss a dose of Nalmefene, take it as soon as you remember, particularly before anticipated alcohol consumption, skip if close to the next scheduled dose, and never double up on medication. Managing missed doses properly helps maintain consistent treatment effectiveness while preventing potential adverse reactions.

What Are the Side Effects of Nalmefene?

The side effects of nalmefene are numerous and vary in severity. Common side effects include Nausea, blurred vision, dizziness, fast, pounding, or irregular heartbeat or pulse, headache, nervousness, and pounding in the ears. Less common side effects include confusion, feeling of warmth or heat, flushing or redness of the skin, sweating, and unusual tiredness or weakness. 

Serious side effects manifest as opiate withdrawal symptoms like body aches, diarrhea, fast heartbeat, fever, runny nose, sneezing, sweating, nausea, vomiting, nervousness, restlessness or irritability, shivering or trembling, stomach cramps, weakness, and goosebumps. Additionally, in rare instances, seizures and loss of consciousness occur, though these are less common and require immediate medical attention. It is essential to monitor these symptoms closely and seek medical help if they persist or worsen.

What Are The Alternatives to Nalmefene For Alcohol Addiction?

Nalmefene is not the only option for treating alcohol addiction. Other medications that help manage alcohol use disorder include Naltrexone, Acamprosate, and Disulfiram.

Here are the common alternatives to Nalmefene in detail.

Naltrexone

Naltrexone is an FDA-approved medication used to treat alcohol use disorder by blocking the effects of alcohol, thereby reducing the urge to drink. It helps in maintaining abstinence by lowering the rewarding effects of alcohol on the brain.

Acamprosate

Acamprosate is a medication that maintains alcohol abstinence by restoring neurotransmitter balance, mainly affecting GABA and glutamine pathways. It is prescribed to prevent relapse after stopping alcohol and is taken as a delayed-release tablet three times daily, with or without food. The medication does not prevent withdrawal symptoms, and its effectiveness relies on ongoing use. By targeting GABA and NMDA receptors, Acamprosate helps restore brain chemistry altered by long-term alcohol consumption.

Disulfiram

Disulfiram is a medication used to treat alcohol use disorder by blocking an enzyme involved in alcohol metabolism. It is not a cure and requires additional therapies such as counseling. FDA approved in 1951, disulfiram should not be used if recent alcohol or certain medications like metronidazole or paraldehyde have been taken. Alcohol consumption within 12 hours before or during Disulfiram treatment, and up to 14 days after stopping, must be avoided. The medication must never be given without the patient’s knowledge.

Can Nalmefene Cure Alcoholism?

No, nalmefene does not cure alcoholism, but it significantly reduces alcohol consumption and the frequency of heavy drinking days among individuals with alcohol dependence (AD) or alcohol use disorder (AUD).

How Long Does Nalmefene Stay in Your System?

Nalmefene stays in your system for approximately 10 to 12 hours when excreted through urine and up to 12.5 hours following oral administration.

How to Find Alcohol Addiction Treatment in New Jersey?

To find a local drug and alcohol rehab center in New Jersey, research accredited facilities that specialize in substance abuse treatment. Contact your insurance provider to understand coverage options. Reach out to the New Jersey Department of Human Services Division of Mental Health and Addiction Services for referrals to state-approved programs. Consider location, treatment approaches, and program duration in your selection. In 2022, 31,807 individuals in New Jersey sought treatment for alcohol addiction, indicating a significant need for quality rehabilitation services in the state.

Right Choice Recovery offers comprehensive alcohol addiction treatment programs tailored to individual needs, including Partial Care, Intensive Outpatient, and Outpatient Services. Our evidence-based therapies address both the physical and psychological aspects of addiction, providing a supportive environment for lasting recovery. Treatment at our facility includes personalized care plans, various therapeutic modalities, and ongoing support through aftercare planning and alumni programs to ensure sustained sobriety.

What Do I Need To Do To Verify My Insurance For Alcohol Addiction Treatment In New Jersey?

To verify insurance for alcohol addiction treatment in New Jersey, complete the online verification form with your personal details and insurance information. The process requires your contact information, the insured’s full name, date of birth, and insurance carrier details, including group number and member ID. 

Right Choice Recovery handles the verification process by contacting your insurance provider directly to determine your coverage benefits for alcohol addiction treatment. For immediate assistance with insurance verification, verify insurance through our secure online form or call (732) 838-6495 to speak with our admissions team, who will guide you through the process and answer any questions about your coverage options.