Withdrawal Symptoms Associated With Specific Drugs

WITHDRAWAL SYMPTOMS ASSOCIATED WITH SPECIFIC DRUGS... 

Flutamide was the first drug used in prostate cancer therapy for which the withdrawal syndrome was reported. In that study, 40% of patients showed a decline in prostate specific antigen (PSA) levels after cessation of flutamide from the therapeutic protocol. The decline in PSA levels was associated with an improvement of the clinical symptoms. Based on these paradoxical observations, the concept of sequenced androgen ablation was proposed [217]. Several phase II clinical studies were performed, demonstrating safety and tolerability, however, a direct comparison in randomised phase III trials is necessary [218]. 

In addition to the previous definition, withdrawal can be further described as the development of a substance-specific syndrome after cessation of or reduction in intake of a substance that was used regularly by the individual to induce a state of intoxication. Withdrawal causes significant distress to the individual and is associated with impairment in social, occupational, or other areas of functioning. Withdrawal is usually associated with substance dependence. Withdrawal generally is also associated with a craving to readminister the drug to relieve the symptoms. 

Bupropion appears to reduce nicotine withdrawal symptoms and may simulate the actions of nicotine on the brain reward system. The most common side-effects related to bupropion are insomnia (30-45% at a dose of 300 mg/day) and dry mouth. Other commonly reported adverse events include hypertension, headache, and nausea. Seizures are a known risk associated with the use of somewhat higher doses compared with other antidepressants (0.1-0.4%), especially for the immediate-release form of the drug and when given at dosages of 450 mg/day or higher. Bupropion, unlike the TCAs, is virtually free of adverse cardiovascular effects, which makes it quite attractive for specific populations. 

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