Drug interactions primary mechanism

Vincristine resistance has been studied in Chinese hamster ovary cell lines cells resistant to vincristine also are resistant to vinblastine and vindesine. Suggestions were made that, in cells with relatively low levels of drug resistance, at least two prominent mechanisms of resistance can occur (22). In the first instance, cellular resistance may be attributable to membrane alterations that are reversible, functionally, by treatment with verapamil. In the second, resistance has been postulated to be due to an altered sensitivity of tubulin to the effects of the drugs the primary basis for postulating an altered interaction with tubulin was that a subgroup of cells resistant to vincristine showed enhanced sensitivity to taxol, a drug that can stabilize microtubules. It should be emphasized that differential sensitivities of tubulins from different tumor cells to the effects of vincristine or vinblastine has been proposed as a basis for the susceptibilities of cells to the cytotoxic effects of such drugs (23). Differences have been described in the electrophoretic patterns for tubulins obtained from vin-... 

Oxcarbazepine is a derivative of carbamazepine and although its precise mechanism of action is unknown it has similar properties as carbamazepine and is also used for the treatment of primary generalized tonic-clonic seizures and partial seizures. Also the adverse effects are similar to those of carbamazepine. However the drug interaction profile is different as oxcarbazepine has hardly any enzyme-inducing capacity. 

Metabolism often plays a central role in the efficacy of a drug and/or the toxicity associated with exposure to a drug or other xenobiotics. Metabolism may convert a prodrug to the pharmacologically active form, and may be a primary determinant of peak plasma concentration and half-life. Alternatively, competition for metabolism may be the mechanism for a drug-drug interaction. 

Describe the primary pharmacokinetic mechanisms that underlie drug interactions. 

It has been generally accepted that anesthetics interact with membrane lipids as a primary step of anesthesia. The detailed mechanism of the anesthetic action is, however, still controversial. This is mainly due to the absence of specific information on delivery sites in membranes. The NMR data for the delivery site of drugs in membranes are of great use. 

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