Re: Бензодиазепиновая зависимость
#46В англоязычной википедии есть статья о эталонном представителе бензидиазепинов диазепаме. Статья довольно подробная, с большим количеством ссылок на источники.
http://en.wikipedia.org/wiki/Diazepam
Не могу не процитировать в разрезе сабжевой дискуссии один раздел от туда:
Tolerance and physical dependence
Diazepam as with other benzodiazepine drugs can cause tolerance, physical dependence, addiction and what is known as the benzodiazepine withdrawal syndrome. Withdrawal from diazepam or other benzodiazepines often leads to withdrawal symptoms that are similar to those seen during barbiturate or alcohol withdrawal. The higher the dose and the longer the drug is taken the greater the risk of experiencing unpleasant withdrawal symptoms. Withdrawal symptoms can occur from standard dosages and also after short-term use and can range from insomnia and anxiety to more serious symptoms including seizures and psychosis. Withdrawal symptoms can sometimes resemble pre-existing conditions and be misdiagnosed. Diazepam may produce less intense withdrawal symptoms due to its long elimination half life. Benzodiazepine treatment should be discontinued as soon as possible via a slow and gradual dose reduction regime.[4][63] Tolerance develops to the therapeutic effects of benzodiazepines; for example tolerance occurs to the anticonvulsant effects and as a result benzodiazepines are not generally recommended for the long-term management of epilepsy. Dose increases may overcome the effects of tolerance, however, tolerance may then develop to the higher dose and adverse effects may increase. The mechanism of tolerance to benzodiazepines includes, uncoupling of receptor sites, alterations in gene expression, down regulation of receptor sites and desensitisation of receptor sites to the effect of GABA. Approximately one third of individuals who take benzodiazepines for longer than 4 weeks become dependent and experience a withdrawal syndrome upon cessation.[4] The difference in rates of withdrawal (50–100%) varies depending on the patient sample being investigated. For example, a random sample of long-term benzodiazepine users typically finds that around 50% will experience little or no withdrawal symptoms, with the other 50% experiencing notable withdrawal symptoms. Certain select patient groups will show a higher rate of notable withdrawal symptoms, up to 100%.[64] Rebound anxiety, more severe than baseline anxiety, is also a common withdrawal symptom when discontinuing diazepam or other benzodiazepines.[65] Diazepam is therefore only recommended for short-term therapy at the lowest possible dose owing to risks of severe withdrawal problems from low doses even after gradual reduction.[66] There is a significant risk of pharmacological dependence on diazepam and patients experiencing symptoms of benzodiazepine withdrawal syndrome if it is taken for 6 weeks or longer.[67] In humans tolerance to the anticonvulsant effects of diazepam occurs frequently.[68]
А вот по клоназепаму:
http://en.wikipedia.org/wiki/Clonazepam
Tolerance and withdrawal
Main article: Benzodiazepine withdrawal syndromeLike all benzodiazepines, clonazepam is a benzodiazepine receptor agonist.[55][56] One third of individuals treated with benzodiazepines for longer than 4 weeks develop a dependence on the drug and experience a withdrawal syndrome upon dose reduction. High dosage and long term use increases the risk and severity of dependence and withdrawal symptoms. Withdrawal seizures and psychosis can occur in severe cases of withdrawal and anxiety and insomnia in less severe cases of withdrawal. Gradual reduction in dosage reduces the severity of the benzodiazepine withdrawal syndrome. Due to the risks of tolerance and withdrawal seizures clonazepam is generally not recommended for the long-term management of epilepsies. Increasing the dose can overcome the effects of tolerance but tolerance to the higher dose may occur and adverse effects may increase. The mechanism of tolerance includes receptor desensitisation, down regulation, receptor uncoupling and alterations in subunit composition and alterations in gene transcription coding.[5]
Tolerance
Tolerance to the anticonvulsant effects of clonazepam occurs in both animals and humans. In humans, tolerance to the anticonvulsant effects of clonazepam occurs frequently.[57][58] Chronic use of benzodiazepines leads to the development of tolerance with a decrease of benzodiazepine binding sites. The degree of tolerance is more pronounced with clonazepam than with chlordiazepoxide.[59] In general, short-term therapy is more effective than long-term therapy with clonazepam for the treatment of epilepsy.[60] Many studies have found that tolerance develops to the anticonvulsant properties of clonazepam with chronic use, which limits its long term effectiveness as an anticonvulsant.[61]
Withdrawal
Abrupt or over-rapid withdrawal from clonazepam may result in the development of the benzodiazepine withdrawal syndrome, causing psychosis characterised by dysphoric manifestations, irritability, aggressiveness, anxiety, and hallucinations.[62][63][64] Sudden withdrawal may also induce the potentially life threatening condition status epilepticus. Antiepileptic drugs, benzodiazepines such as clonazepam in particular, should be reduced slowly and gradually when discontinuing the drug to reduce withdrawal effects.[43] Carbamazepine has been trialed in the treatment of clonazepam withdrawal and has been found to be ineffective in preventing clonazepam withdrawal status epilepticus from occurring.[65]
Обращают на себя внимание заметки о возникновении толерантности не только к анксиолитическому эффекту этих препаратов, но и к противосудорожному. Толерантность - это как раз то явление, которое шагает рука об руку с зависимостью(речь, естественно, о физической зависимости). Если бы препарат только лишь вызывал зависимость(т.е. способность вызывать абстинентный синдром, в случае отмены), но при этом продолжал помогать - это ещё хорошо. Беда как раз в том, что препарат через некоторое время перестаёт действовать.
Вот где сама суть проблемы, вот где драма. Когда препарат уже не действует, не работает, не помогает. Но, в то же время, из-за тяжести синдрома отмены, который не все способны вытерпеть, продолжать приём бесполезного препарата приходится.
Вот это и есть та самая ЗАВИСИМОСТЬ, которая представляет для многих, кто принимает бензо годами, проблему. Настоящую, реальную, НЕ надуманную и никаким своим местом НЕ психологическую проблему.