Starting naltrexone before being fully opioid-free for at least seven to ten days will cause immediate severe withdrawal.
What it treats
Which conditions is Naltrexone used for?
Overview
What is Naltrexone?
Naltrexone is used to help people maintain abstinence from opioids or alcohol after completing detoxification. It completely blocks opioid receptors so that if opioids are used, they produce no effect.
For alcohol use disorder, it reduces the pleasure and craving associated with drinking, making it easier to maintain abstinence or reduce consumption.
It is listed in Kenya's Essential Medicines List 2023. It works best as part of a broader plan that includes psychosocial support, counselling, and community engagement.
How it works
What does it do in the brain?
Formulations in Kenya
How is it available?
Availability across Africa
Where is it available in Africa and what is it called?
| Country | Common Brand Name(s) | Notes |
|---|---|---|
| South Africa | Revia, Naltrexone (generic) | Available on prescription for alcohol and opioid use disorder; stocked at addiction treatment centres. |
| Nigeria | Revia, Naltrexone (generic) | Available at teaching hospital pharmacies and private addiction clinics in major cities. |
| Ghana | Naltrexone (generic) | Available at Korle-Bu Teaching Hospital and select private pharmacies in Accra. |
| Uganda | Naltrexone (generic) | Available at Butabika Hospital and through some private addiction services in Kampala. |
| Tanzania | Naltrexone (generic) | Available at Muhimbili National Hospital for post-detox relapse prevention. |
Side effects
What might you feel while taking it?
These are the most commonly reported effects. Not everyone experiences them, and many settle within the first few weeks.
- Nausea and abdominal discomfort, particularly in the first week
- Reduced appetite
- Headache
- Fatigue and difficulty sleeping
- Low mood in some people, particularly in the early weeks
- If started before being fully free of opioids, naltrexone causes immediate and intense opioid withdrawal, severe and dangerous
- Liver inflammation at very high doses, liver function is checked before starting
- Some people notice low mood in the early weeks, report this to your doctor
Who should not take it
Important warnings before starting
- Currently using opioids or not yet fully detoxified
- Significant liver failure
- Currently taking any opioid-containing medicine
Special care needed
Situations that need extra attention
- Carry information explaining that you are on naltrexone. If you need emergency pain relief, opioid painkillers will not work while naltrexone is active
- After stopping naltrexone, opioid tolerance is reduced. If you relapse, the amount that would previously have been manageable could now cause an overdose.
- Tell your doctor about any liver disease
- Consistent daily use produces the relapse prevention benefit
Limited data. Discuss with your doctor if pregnancy is possible or confirmed.
Insufficient data. Specialist guidance required.
Other medicines
Medicines and substances that can interact with it
- All opioid medicines including codeine, tramadol, morphine: Naltrexone blocks their effect entirely. Pain management during treatment must use non-opioid approaches.
- Opioid-containing cough and diarrhoea medicines: These will not work while naltrexone is active.
Tests and follow-up
What your doctor will monitor
- Liver function tests before starting and periodically during treatment
- Mood and mental health, particularly in the first month
- Adherence and motivation at each appointment
- A urine test before starting to confirm opioid-free status
Stopping this medicine
What happens if you stop taking it?
In Kenya
What you should know about this medicine in Kenya
Naltrexone offers an important option in Kenya's addiction treatment landscape for people who have completed detoxification and are committed to abstinence.
For alcohol use disorder, a condition with a significant and growing burden in Kenya, naltrexone is an evidence-based option that is underused. It works best alongside counselling and social support.
People using naltrexone should be counselled clearly about the change in opioid tolerance that occurs after stopping, particularly given the risk of overdose if relapse follows a period of abstinence.
Sources
References
- Ministry of Health, Kenya. (2023). Kenya Essential Medicines List 2023. Nairobi: Ministry of Health.
- Ministry of Health, Kenya. (2023). Kenya National Medicines Formulary, 1st Edition. Nairobi: Ministry of Health.
- World Health Organization. (2023). Model List of Essential Medicines, 23rd Edition. Geneva: WHO.
- Anton, R. F., et al. (2006). Combined pharmacotherapies and behavioral interventions for alcohol dependence. JAMA, 295(17), 2003-2017.