(2) Switching to a long-acting benzodiazepine. With relatively short-acting benzodiazepines such as alprazolam (Xanax) and lorazepam (Ativan) (
Table 1, Chapter I), it is not possible to achieve a smooth decline in blood and tissue concentrations. These drugs are eliminated fairly rapidly with the result that concentrations fluctuate with peaks and troughs between each dose. It is necessary to take the tablets several times a day and many people experience a "mini-withdrawal", sometimes a craving, between each dose.
For people withdrawing from these potent, short-acting drugs it is advisable to switch to a long-acting, slowly metabolised benzodiazepine such as diazepam. Diazepam (Valium) is one of the most slowly eliminated benzodiazepines. It has a half-life of up to 200 hours, which means that the blood level for each dose falls by only half in about 8.3 days. The only other benzodiazepines with similar half-lives are chlordiazepoxide (Librium), flunitrazepam (Rohypnol) and flurazepam (Dalmane), all of which are converted to a diazepam metabolite in the body. The slow elimination of diazepam allows a smooth, gradual fall in blood level, allowing the body to adjust slowly to a decreasing concentration of the benzodiazepines. The switch-over process needs to be carried out gradually, usually in stepwise fashion, substituting one dose at a time. There are several factors to consider. One is the difference in potency between different benzodiazepines. Many people have suffered because they have been switched suddenly to a different, less potent drug in inadequate dosage because the doctor has not adequately considered this factor. Equivalent potencies of benzodiazepines are shown in
Table 1 (Chapter I), but these are only approximate and differ between individuals.
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