Naltrexone (Revia, Vivitrol)

Question 1

Brands

Answer 1

• Oral - Revia

* Injection - Vivitrol

Question 2

Class

Answer 2

Mu opioid receptor antagonist

Question 3

Use

Answer 3

• Alcohol dependence
• Blocks effects of exogenously administered opioids (oral)
• Prevents relapse in opioid dependence (injection)

Question 4

MOA

Answer 4

• Mu opioid receptor blockade - prevents external opioid receptor binding - prevents pleasurable effects of opioid consumption
• Same with alcohol consumption

Question 5

Augment with

Answer 5

• Acamprosate

* Educate

Question 6

Tests

Answer 6

• For opioid treatment - urine screen for opioids and naloxone challenge test
• None before using for alcohol dependence, may get baseline LFTs

Question 7

S/Es

Answer 7

• N/V, decreased appetite
• Dizziness, dysphoria, anxiety
• injection site reactions (pain, tenderness, itchy, swelling, redness)
• Eosinophilic pneumonia
• Hepatocellular injury at high doses

Question 8

Dosing

Answer 8

*Range -
Oral - 50 mg/day; or 100-100-150 mg on Mon-Wed-Fri
Injection - 380 mg every 4 weeks

*Form -
Tablet 25, 50, 100 mg
Oral solution 12 mg/0.6 mL
IM 380 mg/vial

*Pt has to be opioid free fro 7-10 days before starting; confirm with negative urine screen and/or naloxone challenge test

Question 9

Dosing tips

Answer 9

• Injection- keep refrigerated; use immediately after mixing

* adherence more with injection

Question 10

Overdose

Answer 10

Nausea, abd pain, sedation, dizziness, injection site reaction

Question 11

Long term use upto

Answer 11

1 year

Question 12

Taper or not

Answer 12

No need

Question 13

Half life

Answer 13

Oral - 13 hours

Injection - 5-10 days

Question 14

Drug interactions

Answer 14

• Metabolized by dihydrodiol dehydrogenase in liver
• No CYP action
• Can block effects of some opioid containing meds like cough and cold remedies, antidiarrheal meds, opioid analgesics

Question 15

Warning/precautions

Answer 15

• Hepatocellular injury at high dose
• Pts treated with naltrexone may respond to lower doses of opioids than used earlier, causing opioid OD at lower dose
• Monitor for depressed mood, suicidality
• Caution in psych pts
• Use injection cautiously in thrombocytopenia or bleeding disorders

Question 16

C/I

Answer 16

• Active opioid use
• Acute opiate withdrawal
• Failed naltrexone challenge test or positive urine opioid screen
• Acute hepatitis or liver failure
• Allergy

Question 17

Special populations

Answer 17

• C/I in acute hepatitis or liver failure

* not recommended in pregnancy and BF females

Question 18

advantages

Answer 18

• people not ready to completely quit drinking

* binge drinkers

Question 19

disadvantages

Answer 19

• people who drink over or during t/t, including injection

* people drinking when t/t started

Question 20

Of note

Answer 20

• increases total abstinence
• reduces days of heavy drinking
• some pts complain of apathy or loss of pleasure with chronic use
• naltrexone-bupropion combo used in obesity t/t

Question 21

How long until it works

Answer 21

few days to few weeks

Question 22

Dose for alcohol dependence

Answer 22

• Oral 50 mg/day

* Injection 380 mg IM gluteal every 4 weeks

Question 23

Dose for opioid dependence

Answer 23

*Oral 25 mg/day; increase to 50 mg on day 2