Serum drug concentrations

Develop a plan for monitoring therapeutic outcomes, focusing on the individual symptom profile and level of function of each patient. Include a plan for dosage adjustments or alternate therapy if the patient fails to respond adequately. Include serum drug concentration monitoring as appropriate. 

Monitoring for successful therapy is critical in this serious infection to prevent complications, prevent resistance development, and decrease mortality. Routine assessment of clinical signs and symptoms, as well as laboratory tests (i.e., repeat blood cultures), microbiologic testing and serum drug concentrations, must be performed. 

Evaluate therapeutic serum drug concentrations as appropriate (e.g., vancomycin and gentamicin). 

Therapeutic drug monitoring (TDM) or applied pharmacokinetics is the use of serum drug concentrations to optimize therapy.28,36,37 Non-AIDS patients with drug-susceptible TB... 

SI (le Systeme International d UniUs) units are used in many countries to express clinical laboratory and serum drug concentration data. Instead of employing units of mass (such as micrograms), the SI system uses moles (mol) to represent the amount of a substance. A molar solution contains 1 mol (the molecular weight of the substance in grams) of the solute in 1 L of solution. The following formula is used to convert units of mass to moles (mcg/mL to pmol/L or, by substitution of terms, mg/mL to mmol/L or ng/mL to nmol/L). 

It has been generally assumed that therapeutic serum drug concentration ranges based on data obtained in adults were applicable to children. However, in many instances, when drug response is studied in children, differences in drug distribution and metabolism and in receptor sensitivity rendered this assumption invalid [39]. 

NSAIDs, nonsteroidal antiinflammatory drugs PI, protease inhibitor PT, prothrombin time SDC, serum drug concentrations. 

The evaluation of patients treated for IE includes assessment of signs and symptoms, blood cultures, microbiologic tests (e.g., MIC, minimum bactericidal concentration [MBC], or serum bactericidal titers), serum drug concentrations, and other tests to evaluate organ function. 

Screening for neuropsychiatric disorders is also important. Clinical response is more important than serum drug concentrations. 

Serum drug concentrations if previous anticonvulsant use is suspected or... 

Reich, M.R., Ohad, D.G., Overall, K.L. and Dunham, A.E. (2000) Electrocardiographic assessment of antianxiety medication in dogs and correlation with serum drug concentration [published erratum appears in Journal of American Veterinary Medical Association 2000 216 (12) 1936[. Journal of the American Veterinary Medical Association, 216, 1571-1575. 

Dosage in renal impairment Dosage and frequency are modified based on the degree of renal impairment and serum drug concentration. After a loading dose of 5-7.5 mg/kg, the maintenance dose and frequency are based on serum creatinine levels and creatinine clearance. 

Obtain serum drug concentrations at least 8-12 hr after a dose (preferably prior to next scheduled dose) therapeutic range 0.5-2.0 ng/ml... 

Indications and Dosages Alert During acute phase, a therapeutic serum lithium concentration of 1-1.4 mEq/L is required. For long-term control, the desired level is 0.5-1.3 mEq/L. Monitor serum drug concentration and clinical response to determine proper dosage. 

Bjerkenstedt L, Flyckt L, Overo KF, et al. Relationship between clinical effects, serum drug concentration and serotonin uptake inhibition in depressed patients treated with citalopram. EurJ Clin Pharmacol 1985 28 553-557. 

Foscarnet is available in an intravenous formulation only poor oral bioavailability and gastrointestinal intolerance preclude oral use. Cerebrospinal fluid concentrations are 43-67% of steady-state serum concentrations. Although the mean plasma half-life is 3-6.8 hours, up to 30% of foscarnet may be deposited in bone, with a half-life of several months. The clinical repercussions of this are unknown. Clearance of foscarnet is primarily renal and is directly proportional to creatinine clearance. Serum drug concentrations are reduced approximately 50% by hemodialysis. 

Once-daily administration of modified-release formulation of fluvastatin 80-320 mg/day was generally safe and well tolerated in 40 patients with primary hypercholesterolemia over 13 days (7). However, fluvastatin 640 mg in this formulation was not well tolerated six of seven patients had adverse events, including diarrhea, headache, and rises in serum transaminases. In addition, the pharmacokinetics of fluvastatin were non-linear at this dose, possibly because of saturation of first-pass metabolism, causing higher than expected serum drug concentrations. 

Clearance of foscarnet is primarily by the kidney and is directly proportionate to creatinine clearance. Serum drug concentrations are reduced by approximately 50% following a 3-hour hemodialysis. 

In practice, the monitoring of the serum drug concentration is generally unnecessary but there are criteria which may help the clinician to decide when monitoring is appropriate. These include ... 

Two similar drugs are therapeutically equivalent if they have comparable efficacy and safety. [Note Clinical effectiveness often depends both on maximum serum drug concentrations and the time after administration required to reach peak concentration. Therefore, two drugs that are bioequivalent may not be therapeutically equivalent.]... 

Patients should be chronically monitored for seizure control, side effects, social adjustment, drug interactions, compliance, quality of life, and toxicity. Screening for neuropsychiatric disorders is also important. Clinical response is more important than serum drug concentrations. 

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