Naltrexone hydrochloride tablets
- Drugs List
- Therapeutic Indications
- Dosage
- Administration
- Contraindications
- Precautions and Warnings
- Pregnancy and Lactation
- Side Effects
- Monograph
Presentation
Oral formulations of naltrexone hydrochloride.
Drugs List
Therapeutic Indications
Uses
Maintenance of abstinence in alcohol dependent patients
Opioid antagonist. Maintenance of previously dependent, detoxified patients
Adjunct in prophylactic therapy in the maintenance of detoxified formerly opioid-dependent patients.
Treatment for alcoholism to reduce the risk of relapse, as support treatment in abstinence and to reduce the craving for alcohol.
Dosage
Treatment with naltrexone should only be considered in patients who have remained opioid free for a minimum of 7 to 10 days.
Administration must not be started before a naloxone provocation test is performed and a negative result obtained.
Adults
Opioid detoxification
Initial dose of 25mg followed by 50mg daily. A three times a week dosing schedule may be considered if it is likely to result in better compliance, for example 100mg on Monday, 100mg on Wednesday and 150mg on Friday. Maximum dose on any single day is 150mg due to the higher incidence of side effects.
Alcohol dependence
50mg daily.
The following unlicensed alternative dose may be suitable as an adjunct to reduce the risk of relapse in formerly alcohol-dependent patients:
25mg daily on the first day, then if tolerated, increased to 50mg daily.
Patients with Hepatic Impairment
Use with caution in patients with moderate hepatic impairment. Special attention should be paid to patients with hepatic enzyme levels exceeding three times the normal value.
Additional Dosage Information
As naltrexone is an adjunctive therapy and full recovery from opioid dependence is variable, no standard duration of treatment can be recommended; an initial period of three months should be considered. However, prolonged administration may be necessary.
Naloxone Provocation Test
A naloxone provocation test is recommended to detect the presence of any opioid use: a withdrawal syndrome precipitated by naloxone will be of shorter duration than withdrawal precipitated by naltrexone.
The recommended procedure is as follows:
Intravenous injection of 200micrograms naloxone. If, after 30 seconds, no adverse reactions occur, a further intravenous injection of 600micrograms naloxone may be administered. The patient should be observed for 30 minutes for any detectable sign of withdrawal symptoms.
or
Subcutaneous injection of 800micrograms naloxone. The patient should be observed for 30 minutes for any signs or symptoms of withdrawal.
If any symptoms of withdrawal occur, treatment with naltrexone should not be initiated. However, if the test result is negative treatment may be started.
If there is any doubt that the patient remains opioid-free, treatment should be delayed for 24 hours and the challenge may be repeated with a naloxone dosage of 1.6mg.
If no reaction occurs after this, treatment may be initiated with 25mg of naltrexone hydrochloride administered by mouth.
Before starting treatment the test must be confirmed by urine testing.
A naloxone provocation test should not be made in patients with clinically prominent withdrawal symptoms nor in any case of a positive urine test for opioids.
Administration
Alcohol dependence
Tablets should be taken with a liquid, under fasting conditions.
Contraindications
Children under 18 years
Acute hepatic disorder
Breastfeeding
Galactosaemia
Severe hepatic impairment
Severe renal impairment
Precautions and Warnings
Elderly
Glucose-galactose malabsorption syndrome
Lactose intolerance
Moderate hepatic impairment
Moderate renal impairment
Pregnancy
Advise ability to drive/operate machinery may be affected by side effects
Treatment to be prescribed under the supervision of a specialist
Contains lactose
Perform liver function tests before commencing therapy and during therapy
Screen for opioid use before treatment
Withdrawal symptoms precipitated when used in opioid-dependent patients
Advise patient against the use of opioids during treatment
Hepatic function should be monitored before and during treatment. Changes in hepatic function tests have been described in obese elderly patients receiving naltrexone at doses higher than recommended.
No experience of use in elderly patients for this indication. Liver function test abnormalities have been reported in elderly patients taking naltrexone hydrochloride who have no history of drug abuse.
Naltrexone treatment should be initiated and supervised by a physician experienced in treatment of opioid-addicted and alcohol-addicted patients.
Patients should be warned against the concurrent use of opioids (e.g. in cough medication, anti-diarrhoeal medication) during naltrexone treatment.
During treatment painful conditions should be treated with non-opioid analgesic only.
Where patients require opioid treatment (e.g. analgesia or anaesthesia in an emergency setting), the opioid dose needed to achieve the desired therapeutic effect may be larger than normal. In these cases, respiratory depression and circulatory effects will be more profound and longer lasting. Symptoms related to histamine release may also be manifested more easily.
Patients should be warned that an attempt to overcome the block could result in acute opioid intoxication.
Pregnancy and Lactation
Pregnancy
Use naltrexone hydrochloride with caution during pregnancy.
The manufacturer does not recommend using naltrexone hydrochloride during pregnancy unless the potential benefits outweigh the possible risk. Animal studies have shown teratogenic effects. Human data is limited and as such a potential risk cannot be ruled out.
Lactation
Naltrexone hydrochloride is contraindicated during breastfeeding.
The manufacturer does not recommend breastfeeding whilst taking naltrexone hydrochloride. The presence of naltrexone hydrochloride in human breast milk and the effects on exposed infants are unknown.
Counselling
Advise patients that naltrexone may impair mental and/or physical abilities required for performance of potentially hazardous tasks such as driving a car or operating machinery.
Warn patients against the concurrent use of opioids (e.g. in cough medication, anti-diarrhoeal medication) during treatment.
Warn patients that an attempt to overcome the block could result in acute opioid intoxication.
Side Effects
Abdominal pain
Acne
Agitation
Alopecia
Anxiety
Arthralgia
Asthenopia
Blood pressure changes
Changes in libido
Chest pain
Chills
Confusion
Constipation
Cough
Delayed ejaculation
Depressed mood
Diarrhoea
Disorientation
Disturbances of appetite
Dizziness
Dry mouth
Dysphonia
Dysuria
Ear pain
ECG changes
Erectile dysfunction
Eye swelling
Flatulence
Flushing
Haemorrhoids
Hallucinations
Headache
Hepatic impairment
Hepatitis
Hyperhidrosis
Increased energy
Increased thirst
Insomnia
Irritability
Lachrymation
Lymphadenopathy
Muscle pain
Myalgia
Nasal congestion
Nausea
Nervousness
Nightmares
Oral herpes
Palpitations
Paranoia
Photophobia
Pollakiuria
Pruritus
Rash
Reduction of male potency
Restlessness
Reversible idiopathic thrombocytopenia
Rhabdomyolysis
Rhinorrhoea
Sensations of heat, cold or numbness
Serum bilirubin increased
Sinus disorder
Sneezing
Somnolence
Suicidal tendencies
Tachycardia
Tinea pedis
Tinnitus
Tremor
Ulceration
Vertigo
Visual disturbances
Weight changes
Weight gain
Overdosage
It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.
The following number will direct the caller to the relevant local centre (0844) 892 0111
Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).
Further Information
Last Full Review Date: January 2020
Reference Sources
Summary of Product Characteristics: Adepend 50mg tablets. AOP Orphan Pharmaceuticals. Revised October 2017.
NICE Evidence Services Available at: www.nice.org.uk Last accessed: 17 January 2020
Medscape UK | Univadis prescription drug monographs & interactions are based on FDB Multilex Content
FDB Disclaimer : FDB Multilex is intended for the use of healthcare professionals and is provided on the basis that the healthcare professionals will retain FULL and SOLE responsibility for deciding what treatment to prescribe or dispense for any particular patient or circumstance.