Acamprosate

• acamprosate is believed to act by modulating disturbance in the GABA/glutamate system associated with alcohol dependence - thus leading to a reduction in the risk of relapse during the postwithdrawal period (1)
• not metabolised by the liver and has no interaction with alcohol.
• treatment option for the prevention of relapse following previous alcohol abuse (2)
• first drug licensed for the prevention of relapse that actually reduces desire to drink
• should be initiated as soon as possible after abstinence has been achieved
• should be used in conjunction with specialist alcohol counselling
• does not have a depressive effect
• some guidance suggest that should be continued if the patient relapses - see notes (3). NICE however suggest that (4) acamprosate should be be stopped if drinking persists 4-6 weeks after starting the drug
  
• contra-indications include severe hepatic and renal impairment; also contra-indicated in pregnancy and breast-feeding

NICE state that (4):

• if using acamprosate, start treatment as soon as possible after assisted withdrawal. Usually prescribe at a dose of 1998 mg (666 mg three times a day) unless the service user weighs less than 60 kg, and then a maximum of 1332 mg should be prescribed per day. Acamprosate should:
  • usually be prescribed for up to 6 months, or longer for those benefiting from the drug who want to continue with it
    
• service users taking acamprosate should stay under supervision, at least monthly, for 6 months, and at reduced but regular intervals if the drug is continued after 6 months. Do not use blood tests routinely, but consider them to monitor for recovery of liver function and as a motivational aid for service users to show improvement
  
  

Notes:

• acamprosate is often better taken with food although this may slightly reduce bioavailability. The patient should be advised at the outset that evidence shows that treatment continues to confer benefit for up to 12 months (3)
• acamprosate works best in those who are abstinent but may also reduce the risk of relapse to heavy drinking in those who are drinking (acamprosate does not interact with alcohol), so ongoing alcohol use should not be a reason to stop treatment unless a relapse to heavy drinking is obvious (3)
• before starting treatment with acamprosate, oral naltrexone or disulfiram, conduct a comprehensive medical assessment (baseline urea and electrolytes and liver function tests including gamma glutamyl transferase [GGT]). In particular, consider any contraindications or cautions (see the SPC), and discuss these with the service user (4)

The summary of product characteristics should be consulted before prescribing this drug.

Reference:

1. Prescriber 2004; 15(12):16-25
2. BNF 4.10
3. SMMGP (February 2010). Network;28:12-14.
4. NICE (February 2011). Alcohol-use disorders - Diagnosis, assessment and management of harmful drinking and alcohol dependence