How should we employ pharmacotherapies for alcohol use disorder (AUD) in older adult patients? There are three FDA-approved medications (acamprosate, disulfiram, and naltrexone) and two other commonly used off-label agents (gabapentin and topiramate). But these medications have no established guidelines geared specifically to older adults.
In this primer, I will try to answer the following important questions:
• Do these medications work as well for older adults?
• Should we change the way we decide which medication to start?
• Should we adjust starting dosages and titration schedules?
• Are there specific side effects that we should watch for when treating older adults?
• Do comorbid medical conditions impact our choice of meds?
Factors that make treating older adults more complicated
1. Older adults are more likely to have comorbid medical problems. On average, they have 2.3 chronic medical conditions, the most common being hypertension, hyperlipidemia, arthritis, heart disease, diabetes, and kidney disease (Wolff JL et al, Arch Intern Med 2002;162(20):2269–2276).
2. As a result, older adults take many medications. In fact, it’s estimated that 20%–45% of older adults are on polypharmacy regimens, meaning they take 5 or more medications at the same time (Hosseini SR et al, J Mid-Life Health 2018;9(2):97–103).
3. Older adults also have decreased ability to eliminate medicines.
4. All of this makes older adults more susceptible to adverse drug events. While I can’t go into every potential drug interaction, I’ll consider some of the more significant ones.
The following is a med-by-med rundown of AUD meds in older adults. Because the data are limited, I may not be able to address every question to your satisfaction, but I’ll do my best.
Naltrexone: Oral or extended release injectable (Vivitrol)
Naltrexone is an opioid blocker that reduces the rewarding effects of alcohol, resulting in fewer drinking days and lighter drinking; it also lowers craving. It is the only AUD med studied in older adults so far. The lone study showed that it is effective in preventing relapse in patients who resume drinking (Oslin DW et al, Am J Geriatr Psychiatry 1997;5(4):324–332). Naltrexone also can be a good choice for some patients with comorbid AUD and opioid use disorder (OUD), although buprenorphine and methadone have better data in treating OUD.
Naltrexone has the potential to cause liver damage, though this is very unlikely at recommended doses. More commonly, naltrexone can precipitate opioid withdrawal in patients taking opioids. Before prescribing naltrexone, make sure your older adult patients are not taking any opioids for chronic pain conditions.
Dosing in older adults: Patients should be free from opioids for 7–10 days prior to starting. We recommend beginning at 25 mg daily for 7 days, then increasing to 50 mg daily as tolerated. For extended release naltrexone, administer 380 mg IM q4weeks. The most common side effects of naltrexone are nausea and vomiting. The IM can cause injection site reactions.
Acamprosate is an attractive option for many older adults with AUD, though it has not been studied in this population. While we don’t know exactly how the drug works, people who respond to acamprosate find it reduces craving.
Acamprosate is a small compound that is excreted unchanged by the kidney. You can prescribe it to patients with liver disease, but use it cautiously in patients with moderate to severe renal impairment. It has no known toxic effects on any organ and doesn’t interact with other substances, so it can be a safe agent for patients who take other medications.
Dosing in older adults: The medication comes in 333 mg tablets. Whereas usual guidelines are to start at 666 mg TID, we recommend starting at 333 mg TID in older adults. If the patient doesn’t have side effects, increase to 666 mg TID after 7 days. The most common adverse reactions to acamprosate are diarrhea and flatulence.
Disulfiram is used as a deterrent. A person who drinks alcohol while taking disulfiram will develop an aversive reaction consisting of nausea, flushing, hypotension, shortness of breath, palpitations, and confusion. This can occur up to 2 weeks after taking the medication.
I don’t generally recommend using disulfiram in older adults, because the reaction can be dangerous. Disulfiram can also exacerbate medical conditions common in older persons, like heart disease, diabetes, cerebrovascular disease, chronic renal failure, and peripheral neuropathy. You’ll sometimes read about the risk of psychosis, though I have never seen this side effect. Further, disulfiram can cause liver damage, and by inhibiting liver metabolism, it interacts with many drugs.
Patients who have been taking disulfiram with positive results may feel strongly about continuing it. It could also be used in older patients who are otherwise healthy and taking few medications. Overall, it’s best avoided except in special circumstances.
Dosing in older adults: Disulfiram should be started after the patient has abstained from alcohol for at least 12 hours. Dosing in older adults may need to be on the lower side. The initial dose I favor is 250 mg/day. After 1–2 weeks, the dose can be reduced to 125 mg/day for maintenance therapy (Jacobson SA, Clinical Manual of Geriatric Psychopharmacology, 2nd Edition. Washington DC: American Psychiatric Association Publishing; 2014). Since disulfiram can be sedating, give it at bedtime. Supervised ingestion is likely key to ensuring compliance (Fuller RK and Gordis E, Addiction 2004;99(1):21–24).
Gabapentin has been associated with increased abstinence and reduction in heavy drinking, but it has not been studied for this use in older adults. Side effects include somnolence, headache, dizziness, and ataxia. Some individuals have been noted to misuse gabapentin (See CATR Jan/Feb 2018, “Prescribing Gabapentin for Substance Use Disorders”). It has few significant drug interactions, though lower doses should be used in those with renal impairment. Because of its favorable profile, it can be a good option for older adults with AUD, especially those with comorbid pain or anxiety. Be sure to start low and go slow, as gabapentin is sedating and can increase the risk of falls. Dosing in older adults: Gabapentin can be started at 100 mg/day or BID and gradually increased, based on the patient’s response. I usually don’t go higher than 300 mg TID.
Topiramate has shown benefit in AUD, but it’s best avoided in older adults due to risks of cognitive dysfunction, sedation, falls, osteoporosis, kidney stones, metabolic acidosis, and weight loss. Its serum concentration can also fluctuate due to interactions with other common medications: Lithium and amitriptyline can increase topiramate level, while valproate can decrease it (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2861844/).
CATR VERDICT: For most older adults with AUD, I recommend starting with naltrexone, as it’s the only AUD medication studied in this population, but it won’t be a good choice for everyone. Acamprosate is a reasonable second option. Gabapentin may also be useful. Disulfiram and topiramate should generally be avoided.