Several alcohol use disorder medications have been developed and approved by the FDA, many of which are intended to help individuals who want to quit entirely. This study examined a novel medication treatment tailored specifically for those who want to reduce but not completely eliminate their alcohol use.
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Alcohol use disorder is a major global contributor to morbidity and mortality, responsible for roughly 5% of the world’s disease burden, including premature death and disability. It is linked to over 200 diseases and injury-related health conditions, such as cirrhosis and cancer. The FDA in the United States and regulatory agencies in Europe have approved several medications for the treatment of alcohol use disorder, including acamprosate (also known by the brand name Campral), naltrexone (often prescribed as an extended-release injectable known by the brand name Vivitrol), and disulfiram (known by the brand name Antabuse). Most of these medications are designed for individuals who aim to abstain completely from alcohol. However, many less severe individuals may be either unwilling or feel unable to commit to complete abstinence. As a result, drinking reduction, rather than full abstinence, can operate as a patient-centered treatment goal associated with benefits in functioning that can be sustained over time for individuals who are not ready or do not want to stop entirely.
For people with alcohol use disorder, however, cutting back can be particularly difficult due to alcohol’s reinforcing effects, especially during consumption. Many describe this experience of craving as an inability to stop once they start drinking. This challenge differs from relapse, where an individual returns to alcohol use after previously stopping. On the other hand, craving, or what researchers often refer to as “behavioral sensitization,” (becoming more sensitive the effects of a substance) presents two distinct challenges. First, during alcohol consumption, continued drinking is driven by a subtle sense of discomfort—comparable to thirst—that compels individuals to seek relief, usually through continued alcohol use. Second, the ability to control impulsive behavior becomes impaired, making it harder to make healthy decisions. One theory as to why these impairments tend to coincide with each other is that emerge through the “decoupling” of two critical brain systems: the noradrenergic system and the serotonergic system. Decoupling refers to the lack of coordination between these systems, which normally work together to regulate mood, impulse control, and stress responses.
Much of what we know about the relationship between the brain and addictive behaviors comes from animal studies, where researchers typically induce addiction-like behaviors in mice by administering highly rewarding substances such as cocaine, methamphetamine, opioids, and alcohol. In these types of studies, researchers have also demonstrated that certain medications, which bind to specific receptors in the brain, can reduce the sensitivity to the rewarding effects of the substance (craving), thereby reducing alcohol consumption. For example, cyproheptadine, an antihistamine prescribed to treat allergic reactions, has been shown to block serotonin receptors, while prazosin, a medication used to treat hypertension and urinary urgency, blocks adrenergic receptors. In theory, the result of blocking receptors within these separate systems is that they might get “recoupled,” and become more coordinated.
In this study, the researchers aimed to determine whether a combination of these medications could help these systems become more coordinated and alleviate the discomfort and impulsivity associated with alcohol consumption. Hence, the treatment’s goal is to help individuals achieve their drinking reduction goals by addressing cravings. Specifically, the researchers wanted to see if this medication combination could reduce alcohol consumption in individuals diagnosed with severe alcohol use disorder over a three-month period.
This was a 12-week randomized controlled trial comparing 3 groups – high dose medication, low dose medication, and placebo with outcome assessments at 4, 8, and 12 weeks after study entry. A total of 154 participants meeting DSM-5 criteria for severe alcohol use disorder and the high-risk drinking level criteria of the World Health Organization were enrolled across 32 addiction treatment centers and primary care offices in France between November 2019 and June 2021, with the final visit on October 28, 2021. Notably, because the aim of this study was to test a medication that would be effective for managing craving among people continuing to drink alcohol, participants were excluded from the study if they had been abstinent or recently experienced withdrawal from alcohol.
In the low-dose group, participants took cyproheptadine (4 mg) in the morning and evening, a placebo at noon, and prazosin (5 mg) in the evening. The high-dose group received cyproheptadine (4 mg) 3 times daily (morning, noon, and evening) along with prazosin (5 mg) in the evening. The placebo group received placebo capsules for both medications. Treatments were administered over a 12-week period. The study included a total of 9 visits. The main goal of the study was to measure how much participants reduced their total alcohol consumption in grams of ethanol from the start of the trial to the last month of treatment (weeks 9-12). The researchers wanted to know whether there were real differences in total alcohol consumption between the high- and low-dose groups and the placebo group. Specifically, they wanted to see if the medications could reduce total alcohol consumption by at least 20 grams (slightly less than 1.5 US standard drinks) per day for people in the high-dose group and 10 grams per day for people in the low-dose group, compared to the placebo group. These goals were chosen because they would represent a meaningful improvement for patients.
In addition, the study looked at safety by tracking side effects, such as drowsiness, weight gain, and low blood pressure, as well as other serious adverse events. It also measured other indicators of success, such as the number of heavy drinking days (defined as more than 60 grams of alcohol for men or 40 grams for women), the number of days participants stayed alcohol-free, cravings for alcohol (measured by the Obsessive-Compulsive Drinking Scale), mood (measured by the Beck Depression Inventory), and how many participants reduced their drinking risk level by 2 levels. Another key measure was how many participants reduced their total alcohol intake by at least 50% from the beginning of the study to the third month.
Among the 154 participants initially enrolled, 108 were men (70%) and 46 were women (30%). The average age was 49 years old. The average alcohol consumption per day across all participants in the past month was approximately 109 grams (about 8 standard drinks). There was no significant differences between the 3 groups in terms of total alcohol consumption or any other measure of alcohol use or risk at the start of the study.
The high-dose medication reduced total alcohol consumption
The high-dose group reduced their drinking by 24 grams per day more than the placebo group. However, the low-dose group only reduced their drinking by 18 grams per day more than placebo; this difference did not quite reach statistical significance. As shown in the figure below, the high dose group had substantial reductions by 1 month and continued to decrease alcohol use by 2 months, which was stable out to 3 months (i.e., end of the 12-week trial). Of note, analyses that examined the impact of study drop-out – one that used a statistical technique to impute missing values and one which carried forward a participant’s last observation – showed similar results.
Both medication groups experienced improvements in other alcohol use outcomes
Both the high-dose group (42%) and the low-dose group (34%) were more likely to have a 2-level reduction in WHO risk level compared to placebo (20%). The high-dose group (but generally not the low dose group) also outperformed placebo on several dimensions of the obsessive-compulsive drinking scale. Interestingly, only the low dose group had greater reductions in depression compared to placebo at the 3-month follow-up (but not during the first 2 months of the trial).
Adverse events were common but mostly mild, with no serious adverse events reported in the high-dose group
There were 342 adverse events reported, affecting 73% of participants. Most of these events were mild or moderate. No serious adverse events occurred in the high-dose group, but the low-dose group had 5 serious adverse events among 4 participants. Both the low- and high-dose groups experienced more weight gain compared to the placebo group. Completion rates were high across all groups, with no significant differences in follow-up between them. Desriptively, 54% of the placebo group, 67% of the low-dose group, and 61% of the high-dose group successfully completed the trial with at least 80% adherence to the medication.
The researchers found that the high-dose group of medication combination reduced alcohol consumption to a greater degree than placebo, though the low dose group did not. The most substantial improvements observed in the high-dose treatment group align with 2 key factors: (a) the known mechanisms of action of these medications and (b) the well-established dose-response relationship in treatment, where higher doses typically yield stronger effects.
Despite these promising findings, they also raise important questions about the role of harm reduction strategies within the broader treatment framework. Numerous studies have demonstrated the effectiveness of harm reduction strategies in alleviating the overall burden of substance use disorders, including alcohol use disorder. However, harm reduction may be harder to maintain in the long-term compared to abstinence-based approaches. The risk of perpetuating cravings through continued alcohol use is also higher with harm reduction than with abstinence, due to the previously mentioned effect of behavioral sensitization. Nevertheless, abstinence-based approaches come with their own set of unique challenges and trade-offs.
The researchers also reported that both the high- and low-dose treatment groups showed reductions in impulsivity and negative emotions, alongside decreases in drinking behavior. The improvements in impulsivity and reductions in depression—the primary measures assessed in this study—are critical indicators of sustained recovery. Moreover, these results may support the idea that reducing alcohol consumption can be an important first step for individuals who are not yet ready to commit to complete abstinence. In other words, if individuals start to feel better by drinking less, they may be encouraged to consider how much more improvement they could experience by abstaining from alcohol altogether.
Finally, one notable and related side effect observed in both medication groups was weight gain, which the study’s authors attributed to an increase in appetite. Depending on its magnitude, weight gain poses further health risks, such as obesity, and should be closely monitored. Though study drop-out was generally low and similar between the conditions, the study did not examine whether the difference between the 67% adherence rate in the low-dose group and 61% adherence rate in the high-dose group was statistically significant. It is possible that the medication is harder to tolerate at higher doses, but beyond study drop-out and certain side effect outcomes like weight gain, the impact of medication adherence was not examined here. Weight gain may be an especially relevant side effect for individuals with alcohol use disorder, as self-esteem issues often play a role in relapse. Weight gain could exacerbate negative self-image, potentially undermining their recovery efforts. Thus, an increase in appetite carries significant implications for individuals with current or past alcohol use disorder, as it may affect both physical health and emotional well-being.
The findings from this phase 2 clinical trial suggest that the challenges associated with craving, specifically feelings of discomfort and impulsivity, that accompany alcohol use might be addressed through a medication combination that simultaneously blocks receptors in the adrenergic and serotonergic systems of the brain.
Aubin, H.-J., Berlin, I., Guiraud, J., Bruhwyler, J., Batel, P., Perney, P., Trojak, B., Bendimerad, P., Guillou, M., Bisch, M., Grall-Bronnec, M., Labarrière, D., Delsart, D., Questel, F., Moirand, R., Bernard, P., Trovero, F., Pham, H. P., Tassin, J.-P., & Puech, A. (2024). Prazosin and cyproheptadine in combination in the treatment of alcohol use disorder: A randomized, double-blind, placebo-controlled trial. Addiction, 119(7), 1211-1223. doi: 10.1111/add.16484.
l
Alcohol use disorder is a major global contributor to morbidity and mortality, responsible for roughly 5% of the world’s disease burden, including premature death and disability. It is linked to over 200 diseases and injury-related health conditions, such as cirrhosis and cancer. The FDA in the United States and regulatory agencies in Europe have approved several medications for the treatment of alcohol use disorder, including acamprosate (also known by the brand name Campral), naltrexone (often prescribed as an extended-release injectable known by the brand name Vivitrol), and disulfiram (known by the brand name Antabuse). Most of these medications are designed for individuals who aim to abstain completely from alcohol. However, many less severe individuals may be either unwilling or feel unable to commit to complete abstinence. As a result, drinking reduction, rather than full abstinence, can operate as a patient-centered treatment goal associated with benefits in functioning that can be sustained over time for individuals who are not ready or do not want to stop entirely.
For people with alcohol use disorder, however, cutting back can be particularly difficult due to alcohol’s reinforcing effects, especially during consumption. Many describe this experience of craving as an inability to stop once they start drinking. This challenge differs from relapse, where an individual returns to alcohol use after previously stopping. On the other hand, craving, or what researchers often refer to as “behavioral sensitization,” (becoming more sensitive the effects of a substance) presents two distinct challenges. First, during alcohol consumption, continued drinking is driven by a subtle sense of discomfort—comparable to thirst—that compels individuals to seek relief, usually through continued alcohol use. Second, the ability to control impulsive behavior becomes impaired, making it harder to make healthy decisions. One theory as to why these impairments tend to coincide with each other is that emerge through the “decoupling” of two critical brain systems: the noradrenergic system and the serotonergic system. Decoupling refers to the lack of coordination between these systems, which normally work together to regulate mood, impulse control, and stress responses.
Much of what we know about the relationship between the brain and addictive behaviors comes from animal studies, where researchers typically induce addiction-like behaviors in mice by administering highly rewarding substances such as cocaine, methamphetamine, opioids, and alcohol. In these types of studies, researchers have also demonstrated that certain medications, which bind to specific receptors in the brain, can reduce the sensitivity to the rewarding effects of the substance (craving), thereby reducing alcohol consumption. For example, cyproheptadine, an antihistamine prescribed to treat allergic reactions, has been shown to block serotonin receptors, while prazosin, a medication used to treat hypertension and urinary urgency, blocks adrenergic receptors. In theory, the result of blocking receptors within these separate systems is that they might get “recoupled,” and become more coordinated.
In this study, the researchers aimed to determine whether a combination of these medications could help these systems become more coordinated and alleviate the discomfort and impulsivity associated with alcohol consumption. Hence, the treatment’s goal is to help individuals achieve their drinking reduction goals by addressing cravings. Specifically, the researchers wanted to see if this medication combination could reduce alcohol consumption in individuals diagnosed with severe alcohol use disorder over a three-month period.
This was a 12-week randomized controlled trial comparing 3 groups – high dose medication, low dose medication, and placebo with outcome assessments at 4, 8, and 12 weeks after study entry. A total of 154 participants meeting DSM-5 criteria for severe alcohol use disorder and the high-risk drinking level criteria of the World Health Organization were enrolled across 32 addiction treatment centers and primary care offices in France between November 2019 and June 2021, with the final visit on October 28, 2021. Notably, because the aim of this study was to test a medication that would be effective for managing craving among people continuing to drink alcohol, participants were excluded from the study if they had been abstinent or recently experienced withdrawal from alcohol.
In the low-dose group, participants took cyproheptadine (4 mg) in the morning and evening, a placebo at noon, and prazosin (5 mg) in the evening. The high-dose group received cyproheptadine (4 mg) 3 times daily (morning, noon, and evening) along with prazosin (5 mg) in the evening. The placebo group received placebo capsules for both medications. Treatments were administered over a 12-week period. The study included a total of 9 visits. The main goal of the study was to measure how much participants reduced their total alcohol consumption in grams of ethanol from the start of the trial to the last month of treatment (weeks 9-12). The researchers wanted to know whether there were real differences in total alcohol consumption between the high- and low-dose groups and the placebo group. Specifically, they wanted to see if the medications could reduce total alcohol consumption by at least 20 grams (slightly less than 1.5 US standard drinks) per day for people in the high-dose group and 10 grams per day for people in the low-dose group, compared to the placebo group. These goals were chosen because they would represent a meaningful improvement for patients.
In addition, the study looked at safety by tracking side effects, such as drowsiness, weight gain, and low blood pressure, as well as other serious adverse events. It also measured other indicators of success, such as the number of heavy drinking days (defined as more than 60 grams of alcohol for men or 40 grams for women), the number of days participants stayed alcohol-free, cravings for alcohol (measured by the Obsessive-Compulsive Drinking Scale), mood (measured by the Beck Depression Inventory), and how many participants reduced their drinking risk level by 2 levels. Another key measure was how many participants reduced their total alcohol intake by at least 50% from the beginning of the study to the third month.
Among the 154 participants initially enrolled, 108 were men (70%) and 46 were women (30%). The average age was 49 years old. The average alcohol consumption per day across all participants in the past month was approximately 109 grams (about 8 standard drinks). There was no significant differences between the 3 groups in terms of total alcohol consumption or any other measure of alcohol use or risk at the start of the study.
The high-dose medication reduced total alcohol consumption
The high-dose group reduced their drinking by 24 grams per day more than the placebo group. However, the low-dose group only reduced their drinking by 18 grams per day more than placebo; this difference did not quite reach statistical significance. As shown in the figure below, the high dose group had substantial reductions by 1 month and continued to decrease alcohol use by 2 months, which was stable out to 3 months (i.e., end of the 12-week trial). Of note, analyses that examined the impact of study drop-out – one that used a statistical technique to impute missing values and one which carried forward a participant’s last observation – showed similar results.
Both medication groups experienced improvements in other alcohol use outcomes
Both the high-dose group (42%) and the low-dose group (34%) were more likely to have a 2-level reduction in WHO risk level compared to placebo (20%). The high-dose group (but generally not the low dose group) also outperformed placebo on several dimensions of the obsessive-compulsive drinking scale. Interestingly, only the low dose group had greater reductions in depression compared to placebo at the 3-month follow-up (but not during the first 2 months of the trial).
Adverse events were common but mostly mild, with no serious adverse events reported in the high-dose group
There were 342 adverse events reported, affecting 73% of participants. Most of these events were mild or moderate. No serious adverse events occurred in the high-dose group, but the low-dose group had 5 serious adverse events among 4 participants. Both the low- and high-dose groups experienced more weight gain compared to the placebo group. Completion rates were high across all groups, with no significant differences in follow-up between them. Desriptively, 54% of the placebo group, 67% of the low-dose group, and 61% of the high-dose group successfully completed the trial with at least 80% adherence to the medication.
The researchers found that the high-dose group of medication combination reduced alcohol consumption to a greater degree than placebo, though the low dose group did not. The most substantial improvements observed in the high-dose treatment group align with 2 key factors: (a) the known mechanisms of action of these medications and (b) the well-established dose-response relationship in treatment, where higher doses typically yield stronger effects.
Despite these promising findings, they also raise important questions about the role of harm reduction strategies within the broader treatment framework. Numerous studies have demonstrated the effectiveness of harm reduction strategies in alleviating the overall burden of substance use disorders, including alcohol use disorder. However, harm reduction may be harder to maintain in the long-term compared to abstinence-based approaches. The risk of perpetuating cravings through continued alcohol use is also higher with harm reduction than with abstinence, due to the previously mentioned effect of behavioral sensitization. Nevertheless, abstinence-based approaches come with their own set of unique challenges and trade-offs.
The researchers also reported that both the high- and low-dose treatment groups showed reductions in impulsivity and negative emotions, alongside decreases in drinking behavior. The improvements in impulsivity and reductions in depression—the primary measures assessed in this study—are critical indicators of sustained recovery. Moreover, these results may support the idea that reducing alcohol consumption can be an important first step for individuals who are not yet ready to commit to complete abstinence. In other words, if individuals start to feel better by drinking less, they may be encouraged to consider how much more improvement they could experience by abstaining from alcohol altogether.
Finally, one notable and related side effect observed in both medication groups was weight gain, which the study’s authors attributed to an increase in appetite. Depending on its magnitude, weight gain poses further health risks, such as obesity, and should be closely monitored. Though study drop-out was generally low and similar between the conditions, the study did not examine whether the difference between the 67% adherence rate in the low-dose group and 61% adherence rate in the high-dose group was statistically significant. It is possible that the medication is harder to tolerate at higher doses, but beyond study drop-out and certain side effect outcomes like weight gain, the impact of medication adherence was not examined here. Weight gain may be an especially relevant side effect for individuals with alcohol use disorder, as self-esteem issues often play a role in relapse. Weight gain could exacerbate negative self-image, potentially undermining their recovery efforts. Thus, an increase in appetite carries significant implications for individuals with current or past alcohol use disorder, as it may affect both physical health and emotional well-being.
The findings from this phase 2 clinical trial suggest that the challenges associated with craving, specifically feelings of discomfort and impulsivity, that accompany alcohol use might be addressed through a medication combination that simultaneously blocks receptors in the adrenergic and serotonergic systems of the brain.
Aubin, H.-J., Berlin, I., Guiraud, J., Bruhwyler, J., Batel, P., Perney, P., Trojak, B., Bendimerad, P., Guillou, M., Bisch, M., Grall-Bronnec, M., Labarrière, D., Delsart, D., Questel, F., Moirand, R., Bernard, P., Trovero, F., Pham, H. P., Tassin, J.-P., & Puech, A. (2024). Prazosin and cyproheptadine in combination in the treatment of alcohol use disorder: A randomized, double-blind, placebo-controlled trial. Addiction, 119(7), 1211-1223. doi: 10.1111/add.16484.
l
Alcohol use disorder is a major global contributor to morbidity and mortality, responsible for roughly 5% of the world’s disease burden, including premature death and disability. It is linked to over 200 diseases and injury-related health conditions, such as cirrhosis and cancer. The FDA in the United States and regulatory agencies in Europe have approved several medications for the treatment of alcohol use disorder, including acamprosate (also known by the brand name Campral), naltrexone (often prescribed as an extended-release injectable known by the brand name Vivitrol), and disulfiram (known by the brand name Antabuse). Most of these medications are designed for individuals who aim to abstain completely from alcohol. However, many less severe individuals may be either unwilling or feel unable to commit to complete abstinence. As a result, drinking reduction, rather than full abstinence, can operate as a patient-centered treatment goal associated with benefits in functioning that can be sustained over time for individuals who are not ready or do not want to stop entirely.
For people with alcohol use disorder, however, cutting back can be particularly difficult due to alcohol’s reinforcing effects, especially during consumption. Many describe this experience of craving as an inability to stop once they start drinking. This challenge differs from relapse, where an individual returns to alcohol use after previously stopping. On the other hand, craving, or what researchers often refer to as “behavioral sensitization,” (becoming more sensitive the effects of a substance) presents two distinct challenges. First, during alcohol consumption, continued drinking is driven by a subtle sense of discomfort—comparable to thirst—that compels individuals to seek relief, usually through continued alcohol use. Second, the ability to control impulsive behavior becomes impaired, making it harder to make healthy decisions. One theory as to why these impairments tend to coincide with each other is that emerge through the “decoupling” of two critical brain systems: the noradrenergic system and the serotonergic system. Decoupling refers to the lack of coordination between these systems, which normally work together to regulate mood, impulse control, and stress responses.
Much of what we know about the relationship between the brain and addictive behaviors comes from animal studies, where researchers typically induce addiction-like behaviors in mice by administering highly rewarding substances such as cocaine, methamphetamine, opioids, and alcohol. In these types of studies, researchers have also demonstrated that certain medications, which bind to specific receptors in the brain, can reduce the sensitivity to the rewarding effects of the substance (craving), thereby reducing alcohol consumption. For example, cyproheptadine, an antihistamine prescribed to treat allergic reactions, has been shown to block serotonin receptors, while prazosin, a medication used to treat hypertension and urinary urgency, blocks adrenergic receptors. In theory, the result of blocking receptors within these separate systems is that they might get “recoupled,” and become more coordinated.
In this study, the researchers aimed to determine whether a combination of these medications could help these systems become more coordinated and alleviate the discomfort and impulsivity associated with alcohol consumption. Hence, the treatment’s goal is to help individuals achieve their drinking reduction goals by addressing cravings. Specifically, the researchers wanted to see if this medication combination could reduce alcohol consumption in individuals diagnosed with severe alcohol use disorder over a three-month period.
This was a 12-week randomized controlled trial comparing 3 groups – high dose medication, low dose medication, and placebo with outcome assessments at 4, 8, and 12 weeks after study entry. A total of 154 participants meeting DSM-5 criteria for severe alcohol use disorder and the high-risk drinking level criteria of the World Health Organization were enrolled across 32 addiction treatment centers and primary care offices in France between November 2019 and June 2021, with the final visit on October 28, 2021. Notably, because the aim of this study was to test a medication that would be effective for managing craving among people continuing to drink alcohol, participants were excluded from the study if they had been abstinent or recently experienced withdrawal from alcohol.
In the low-dose group, participants took cyproheptadine (4 mg) in the morning and evening, a placebo at noon, and prazosin (5 mg) in the evening. The high-dose group received cyproheptadine (4 mg) 3 times daily (morning, noon, and evening) along with prazosin (5 mg) in the evening. The placebo group received placebo capsules for both medications. Treatments were administered over a 12-week period. The study included a total of 9 visits. The main goal of the study was to measure how much participants reduced their total alcohol consumption in grams of ethanol from the start of the trial to the last month of treatment (weeks 9-12). The researchers wanted to know whether there were real differences in total alcohol consumption between the high- and low-dose groups and the placebo group. Specifically, they wanted to see if the medications could reduce total alcohol consumption by at least 20 grams (slightly less than 1.5 US standard drinks) per day for people in the high-dose group and 10 grams per day for people in the low-dose group, compared to the placebo group. These goals were chosen because they would represent a meaningful improvement for patients.
In addition, the study looked at safety by tracking side effects, such as drowsiness, weight gain, and low blood pressure, as well as other serious adverse events. It also measured other indicators of success, such as the number of heavy drinking days (defined as more than 60 grams of alcohol for men or 40 grams for women), the number of days participants stayed alcohol-free, cravings for alcohol (measured by the Obsessive-Compulsive Drinking Scale), mood (measured by the Beck Depression Inventory), and how many participants reduced their drinking risk level by 2 levels. Another key measure was how many participants reduced their total alcohol intake by at least 50% from the beginning of the study to the third month.
Among the 154 participants initially enrolled, 108 were men (70%) and 46 were women (30%). The average age was 49 years old. The average alcohol consumption per day across all participants in the past month was approximately 109 grams (about 8 standard drinks). There was no significant differences between the 3 groups in terms of total alcohol consumption or any other measure of alcohol use or risk at the start of the study.
The high-dose medication reduced total alcohol consumption
The high-dose group reduced their drinking by 24 grams per day more than the placebo group. However, the low-dose group only reduced their drinking by 18 grams per day more than placebo; this difference did not quite reach statistical significance. As shown in the figure below, the high dose group had substantial reductions by 1 month and continued to decrease alcohol use by 2 months, which was stable out to 3 months (i.e., end of the 12-week trial). Of note, analyses that examined the impact of study drop-out – one that used a statistical technique to impute missing values and one which carried forward a participant’s last observation – showed similar results.
Both medication groups experienced improvements in other alcohol use outcomes
Both the high-dose group (42%) and the low-dose group (34%) were more likely to have a 2-level reduction in WHO risk level compared to placebo (20%). The high-dose group (but generally not the low dose group) also outperformed placebo on several dimensions of the obsessive-compulsive drinking scale. Interestingly, only the low dose group had greater reductions in depression compared to placebo at the 3-month follow-up (but not during the first 2 months of the trial).
Adverse events were common but mostly mild, with no serious adverse events reported in the high-dose group
There were 342 adverse events reported, affecting 73% of participants. Most of these events were mild or moderate. No serious adverse events occurred in the high-dose group, but the low-dose group had 5 serious adverse events among 4 participants. Both the low- and high-dose groups experienced more weight gain compared to the placebo group. Completion rates were high across all groups, with no significant differences in follow-up between them. Desriptively, 54% of the placebo group, 67% of the low-dose group, and 61% of the high-dose group successfully completed the trial with at least 80% adherence to the medication.
The researchers found that the high-dose group of medication combination reduced alcohol consumption to a greater degree than placebo, though the low dose group did not. The most substantial improvements observed in the high-dose treatment group align with 2 key factors: (a) the known mechanisms of action of these medications and (b) the well-established dose-response relationship in treatment, where higher doses typically yield stronger effects.
Despite these promising findings, they also raise important questions about the role of harm reduction strategies within the broader treatment framework. Numerous studies have demonstrated the effectiveness of harm reduction strategies in alleviating the overall burden of substance use disorders, including alcohol use disorder. However, harm reduction may be harder to maintain in the long-term compared to abstinence-based approaches. The risk of perpetuating cravings through continued alcohol use is also higher with harm reduction than with abstinence, due to the previously mentioned effect of behavioral sensitization. Nevertheless, abstinence-based approaches come with their own set of unique challenges and trade-offs.
The researchers also reported that both the high- and low-dose treatment groups showed reductions in impulsivity and negative emotions, alongside decreases in drinking behavior. The improvements in impulsivity and reductions in depression—the primary measures assessed in this study—are critical indicators of sustained recovery. Moreover, these results may support the idea that reducing alcohol consumption can be an important first step for individuals who are not yet ready to commit to complete abstinence. In other words, if individuals start to feel better by drinking less, they may be encouraged to consider how much more improvement they could experience by abstaining from alcohol altogether.
Finally, one notable and related side effect observed in both medication groups was weight gain, which the study’s authors attributed to an increase in appetite. Depending on its magnitude, weight gain poses further health risks, such as obesity, and should be closely monitored. Though study drop-out was generally low and similar between the conditions, the study did not examine whether the difference between the 67% adherence rate in the low-dose group and 61% adherence rate in the high-dose group was statistically significant. It is possible that the medication is harder to tolerate at higher doses, but beyond study drop-out and certain side effect outcomes like weight gain, the impact of medication adherence was not examined here. Weight gain may be an especially relevant side effect for individuals with alcohol use disorder, as self-esteem issues often play a role in relapse. Weight gain could exacerbate negative self-image, potentially undermining their recovery efforts. Thus, an increase in appetite carries significant implications for individuals with current or past alcohol use disorder, as it may affect both physical health and emotional well-being.
The findings from this phase 2 clinical trial suggest that the challenges associated with craving, specifically feelings of discomfort and impulsivity, that accompany alcohol use might be addressed through a medication combination that simultaneously blocks receptors in the adrenergic and serotonergic systems of the brain.
Aubin, H.-J., Berlin, I., Guiraud, J., Bruhwyler, J., Batel, P., Perney, P., Trojak, B., Bendimerad, P., Guillou, M., Bisch, M., Grall-Bronnec, M., Labarrière, D., Delsart, D., Questel, F., Moirand, R., Bernard, P., Trovero, F., Pham, H. P., Tassin, J.-P., & Puech, A. (2024). Prazosin and cyproheptadine in combination in the treatment of alcohol use disorder: A randomized, double-blind, placebo-controlled trial. Addiction, 119(7), 1211-1223. doi: 10.1111/add.16484.
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