Metabohzer extensive metabolizer

Benzodiazepines are well absorbed, and the oral route is preferred in most situations. In the treatment of status epilepticus, the preferred route is usually intravenous. Benzodiazepines are extensively metabolized by the microsomal drug-metabohzing system frequently an active compound is broken down to another agent that is also active pharmacologically. This is the reason for the long duration of action of several benzodiazepines. 

Aromatase inhibitors may be classified into two types. Type 1 aromatase inhibitors bind to the aromatase enzyme irreversibly, so they are called inactivators. In some cases they are dubbed mechanism-based or suicide inhibitors when they are metabolized by the enzyme into reactive intermediates that bind covalently to the active site. Type 1 aromatase inhibitors are usually steroidal in structure as represented by exemestane (1), formestane (13), and atamestane (14). Formestane (13) was launched by Ciba-Geigy in 1992. As formestane (13) is readily and extensively metabohzed when administered orally, it is used as a depot formulation for injection. 

As more adults with ADHD are being treated with methylphenidate, the possibility of drug interactions with methylphenidate increases (9). However, based on a study in extensive and poor CYP2D6 metabohzers, it has been suggested that CYP2D6 is not involved in the metabolism of methylphenidate, and that drugs that are inhibitors of CYP2D6 should not affect methylphenidate plasma concentrations (10). 

The second case refers to hormones, pharmaceuticals, and other compounds that are ingested, metabolized, and excreted by mammals (Table 1). Usually a hormone or pharmaceutical is extensively metabohzed in the body and is excreted by mammals as a mixture of different metabolites. Although the general belief is that metabolism renders a drug more water soluble and consequently less hazardous for the aquatic environment, there are exceptions for pro-drugs and specifically acting metabolites. The third case refers to environmental transformation products of pesticides and other environmental pollutants (Table 1), which are formed both by abiotic and biotic transformation processes. 

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