Creating a new problem: The use of baclofen in the management of alcohol use disorder (Drug and Alcohol Review, 2016)
Autoren: W. Akosile & M. Klan
(pp, 03.06.2016)
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Struktur des Inhalts
Der Volltext im englischen Original
Baclofen is a gamma-aminobutyric acid (GABA)-B agonist, licensed as a muscle relaxant and used in the treatment of spasticity [1]. There is mixed evidence in the literature about the use of baclofen in the management of alcohol use disorder [1–3]. However, there is some suggestion from a case report that under-dosing patients may explain the absence of effects [4].There is evidence that baclofen may be effective in the management of a number of psychiatric illnesses [1], anxiety disorder [5] and post-traumatic stress disorder [1,6], reduces the severity of binge eating in women with bulimia or binge eating disorder [7], and reduces severity of withdrawal symptoms in other substance use disorders [1]. Baclofen is structurally similar to GABA and also acts on GABA-A receptors [8]. Previous authors have suggested that its activity on GABA-A receptors may mediate its abuse potential [9]. Previous researchers have reported cases of patients experiencing delirium or withdrawal after abruptly stopping oral or intrathecal use of baclofen [10]. There is also evidence that patients can develop tolerance (escalating use) after commencing intrathecal baclofen [11], but we know of no case reports of patients developing use disorders after prescription of baclofen for the management of alcohol use disorder. We report the case of a 26-year-old man with polysubstance use disorder (past amphetamine use, current nicotine and alcohol use) who had been prescribed baclofen (25 mg three times daily) in March 2014 for the management of alcohol use disorder. Within the first month of use, he had begun using 50–75 mg as a pro re nata while socialising around alcohol to curb cravings, with good effect. Over the next 5 months, he increased his use steadily, and by August 2014 was using up to 500 mg per day. At no stage was any intoxication, euphoria or sedation noted by the patient. The patient abruptly ceased baclofen use while travelling and developed withdrawal symptoms at roughly 36 h after his last use. These symptoms were described by the patient to include symptoms similar to benzodiazepine withdrawal (diaphoresis, tremors, insomnia), and an unusual paraesthesia sensation. The latter was described as similar to formication (which the patient had previously experienced in alcohol withdrawal), but much ‘deeper’.The experience was described as ‘a snail with spikes crawling around the body’ deep under the skin, but was not associated with visual hallucinations or delusions. The sensation was noted to be most prominent at the anterior neck and medial anterior chest, and was the most distressing aspect of his withdrawal syndrome. The patient attempted to decrease the amount of baclofen taken with the aid of his general practitioner, with moderate success. Attempts to reduce the amount below 200 mg per day were limited by withdrawal symptoms, for which the patient used diazepam (up to 30 mg/day) with only mild success. On admission for inpatient detoxification, the patient was put on a tapering dose of diazepam (initial dose 80 mg/day in divided incremental doses, decrease over 12 days) and baclofen (initial dose 30 mg/day, decrease over 7 days). The patient developed symptoms on the second night of admission, the most concerning being the paraesthesia previously described. This was treated with risperidone 1 mg three times daily for the first 3 days, and then promethazine 25 mg pro re nata nocte afterward, with both agents giving good relief. The patient’s Benzodiazepine Withdrawal Scale scoring was persistently high on the subjective measures—38/68 at admission, peak 64/68 at morning of day 3 (67 h after admission) [12]. Objective scoring of benzodiazepines withdrawal symptoms remained low throughout the admission. The patient was discharged at day 13, with the intention of undergoing a residential rehabilitation program. The patient had a symptom profile in keeping with diagnostic and statistical manual of mental disorders, fifth edition (DSM-V) severe substance use disorder in showing; tolerance, a withdrawal syndrome, difficulty stopping use of baclofen, cravings for baclofen and use in larger amounts than intended [13]. It is also important to note that, unlike in many of the reported cases of baclofen withdrawal and delirium, where management comprises high doses of baclofen and subsequent tapering [10], he improved on regular fixed doses of benzodiazepines, pro re nata risperidone and promethazine, and only small tapering doses of baclofen. This finding is in contrast to a previous case report that reported that benzodiazepines were not useful in the treatment of baclofen withdrawal and delirium [8]. Indeed, our patient’s withdrawal syndrome was characteristic of benzodiazepine withdrawal syndrome, but with prominent formication-like paraesthesia. Although there is mixed evidence for the use of baclofen in the treatment of alcohol use disorder [1,2], the potential for it creating problems of ist own when used in very high doses, notably the potential for a DSM-V severe substance use disorder, needs to be considered.
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Kommentar von Baclofen-Wiki
Dieser Kurzreport beginnt mit der längst widerlegten Behauptung, dass Baclofen zwar ein GABA-B-Agonist sei, aber aufgrund der Strukturverwandtschaft mit GABA auch am GABA-A-Rezeptor wirke und deshalb abhängig machen könne. Die Autoren berufen sich bei dieser irrtümlichen Annahme auf einen älteren Text von Olmedo & Hoffmann (2000), der wiederum von Nasti & Brakoulias (2011) aufgegriffen und von den im Arznei-Telegramm zitierten Autoren Akosile & Klan (2016) deshalb vermeintlich als verifiziert eingestuft wurde. Überhaupt erinnert der Report von Akosile & Klan (2016) in Aufbau und Sprache mitunter auf geradezu „plagiierende“ Weise an die Arbeit von Nasti & Brakoulias (2011). Unter dieser falschen Voraussetzung passt dann natürlich der folgende Fallbericht über einen 26-jährigen Patienten mit polytoxer Suchtgeschichte (früherer Amphetaminmissbrauch, gegenwärtige Nikotin- und Alkoholabhängigkeit) prima ins Bild. Besagter Patient sprach im ersten Monat positiv auf 3 x 25 mg Baclofen zur Unterdrückung von Craving an. Nachdem er seine Tagesdosis in den folgenden fünf Monaten auf 500 mg gesteigert hatte (ohne nennenswerte unerwünschte Arzneimittelwirkungen), setzte er Baclofen abrupt ab und erlebte nach eigenen Angaben daraufhin ähnliche Entzugserscheinungen wie bei einem klassischen Benzodiazepin- resp. Alkoholentzug (Diaphorese, Tremor, Schlafstörungen, Parästhesien). Was hier als gefährliche Nebenwirkung einer hochdosierten Baclofenbehandlung hochstilisiert wird, ist lange bekannt: Genau wie z. B. Antidepressiva oder Neuroleptika sollte auch Baclofen nicht abrupt abgesetzt, sondern langsam ausgeschlichen werden. Was bei einer kompetenten medizinischen Begleitung in der Regel auch bekannt und gewährleistet ist. (pp, 12.06.2016)
