Concentration metabolic monitoring

CALCIUM CHANNEL BLOCKERS ANTIGOUT DRUGS Serum concentrations pf verapamil are significantly 1 when co-administered with sulfinpyrazone Uncertain, but presumed to be due to t hepatic metabolism Monitor PR and BP at least weekly until stable. Watch for poor response to verapamil... 

CALCIUM CHANNEL BLOCKERS CALCIUM CHANNEL BLOCKERS Co-administration of nifedipine and diltiazem leads to t plasma concentrations of both drugs Uncertain, but presumed mutual inhibition of CYP3A isoform-mediated metabolism Monitor PR, BP and ECG at least weekly until stable. Warn patients to report symptoms of hypotension (light-headedness, dizziness on standing, etc.)... 

ST JOHN S WORT VINCA ALKALOIDS -VINBLASTINE, VINCRISTINE L of plasma concentrations of vinblastine and vincristine, with risk of inadequate therapeutic response. Reports of AUC 1 by 40%, elimination half-life 1 by 35%, and clearance t by 63% in patients with brain tumours taking vincristine Due to induction of CYP3A4-mediated metabolism Monitor for clinical efficacy, and T dose of vinblastine and vincristine as clinically indicated in the latter case, monitor clinically and radiologi-cally for clinical efficacy in patients with brain tumours, and T dose to obtain the desired response... 

CICLOSPORIN GRISEOFULVIN 1 plasma concentrations of ciclosporin (may be as much as 40%) and risk of rejection in patients who have received transplants Induction of ciclosporin metabolism Monitor ciclosporin levels closely... 

OESTROGENS ANTICANCER AND IMMUNOMODULATING DRUGS - cidosporin, corticosteroids, tacrolimus Possibly t plasma concentrations of these immunomodulating drugs Inhibition of metabolism Monitor blood levels of these drugs warn patients to report symptoms such as fever and sore throat... 

It is important to monitor closely serum blood levels of chloramphenicol, particularly in patients with impaired liver or kidney function or when administering chloramphenicol with other drugs metabolized by the liver. Blood concentration levels exceeding 25 mcg/mL increase the risk of the patient developing bone marrow depression. 

HYDANTOINS Fhenytoin is the most commonly prescribed anticonvulsant because of its effectiveness and relatively low toxicity. However, a genetically linked inability to metabolize phenytoin has been identified. For this reason, it is important to monitor serum concentrations of the drug on a regular basis to detect signs of toxicity Fhenytoin is administered orally and parenterally. If the drug is administered parenterally, the IV route is preferred over the intramuscular route because erratic absorption of phenytoin causes pain and muscle damage at the injection site... 

Hyperglycemia is the most common metabolic complication. A too rapid infuson of amino add-carbohydrate mixtures may result in hyperglycemia, glycosuria, mental confuson, and loss of consciousness Blood glucose levels may be obtained every 4 to 6 hours to monitor for hyperglycemia and guide the dosage of dextrose and insulin (if required). To minimize these complications the primary health care provider may decrease the rate of administration, reduce the dextrose concentration, or administer insulin. 

Spin probes are quite readily metabolized reductively by cells and have been utilized to monitor metabolic activity (lannore etal., 1990) The line widths of the e.s.r. signals are also sensitive to the presence of O2 in both intracellular and extracellular environments and hence O2 concentrations may be determined with TBN or alternative spin probes (Glockner and Swartz, 1991). 

If an aromatic compound reacts with an OH radical to form a specific set of hydroxylated products that can be accurately identified and quantified in biological samples, and one or more of these products are not identical to naturally occurring hydroxylated species, i.e. not produced by normal metabolic processes, then the identification of these unnatural products can be used to monitor OH radical activity therein. This is likely to be the case if the aromatic detector molecule is present at the sites of OH radical generation at concentrations sufficient to compete with any other molecules that might scavenge OH radical. 

While generally not of major concern, omeprazole may inhibit the metabolism of warfarin, diazepam, and phenytoin lansoprazole may decrease theophylline concentrations. Drug interactions with omeprazole are of particular concern in patients who are considered slow metabolizers, as are approximately 3% of the Caucasian population. Unfortunately, it is unclear which patients have the polymorphic gene variation that makes them slow metabolizers.17 The metabolism of esomeprazole may also be altered in patients with this polymorphic gene variation. Patients on potentially interacting drugs should be monitored for development of drug-related problems. 

CYP3A4 and 2D6 are the major enzymes involved in the metabolism of galantamine. Pharmacokinetic studies with inhibitors of this system have resulted in increased galantamine concentrations or reductions in clearance. Similarly to donepezil, if inhibitors are given concurrently with galantamine, monitoring for increased cholinergic side effects should be done. Studies with inducers of these enzymes have not been completed.37... 

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