This is pretty much the simplest model of maintenance dosing When it is given by continuous infusion the drug accumulates gradually. The timeframe for maintenance therapy is up to the oncologist, patient, and insurance company. Jenne, J. W., et al. Such drugs need only a low maintenance dose in order to keep the amount of the drug in the body at the appropriate level, but this also means that, without an initial higher dose, it would take a long time for the amount of the drug in the body to reach that level. Clinical Pharmacology & Therapeutics 13.3 (1972): 349-360. Consolidation chemo, which is often the intent behind adjuvant chemo, is a stronger dose that the doctor hopes will wipe out any remaining malignant cells.
It is an example of how the loading or maintenance dose should remain unchanged; instead the dosing interval should be extended. If the therapeutic index is narrow, dosing the drug too infrequently will give rise to alternation periods of toxicity and ineffectiveness. Other drugs will be different. Even if a second-line therapy is intended, there is an interim period. Birkett's 1996 article for the Australian Prescriber, "The effect of pathophysiology on pharmacokinetics in the critically ill patient—concepts appraised by the example of antimicrobial agents. Although the gains in cancer treatment come slowly, there is progress, and a greater percentage of patients is making it through first-line treatment with a good prognosis. The term is used to distinguish regular or precautionary maintenance from fixing things that are broken. Even though Birkett's 1996 article for the Australian Prescriber is virtually identical to the 2009 book chapter (and is available for free), one might still for some reason want to read other things. The Journal of Clinical Pharmacology 32.7 (1992): 597-602. Drugs.com provides accurate and independent information on more than 24,000 prescription drugs, over-the-counter medicines and natural products.
", "Pharmacokinetic-based design and modification of dosage regimens. As discussed in the chapter on half-life, this is because increasing drug concentration usually results in a more rapid rate of elimination, and eventually the plasma drug concentration reaches a point at which the dose rate and the clearance rate are equal. A loading dose rapidly achieves the peak concentration necessary to compete with clearance, so that the desired effect is achieved and maintained sooner. Apart from equations, "points were awarded for explaining the rationale for giving a loading dose and for relevant diagrams", as well as examples of drugs. For example, in HVAC preventive maintenance, inspecting and changing filters are typically the first steps, followed by cleaning the entire system. Continuing the maintenance dose for about 4 to 5 half lives (t½) of the drug will approximate the steady state level. ", "Dosage regimen design: pharmacodynamic considerations. More patients are being put on maintenance therapy for two good reasons. Generally speaking, for most drugs, the dosing interval is approximately one half life. It usually lasts two to three years for blood cancer patients. Drug Storage & Maintenance 1. There are also decent articles by Williams (1992) and Thompson (1992) Neither is available as free text, and so one would need to engage in some level of institutional access whoring or some sort of darkweb shenanigans to get hold of them. As the examiners expect graphs and examples, it might be helpful to illustrate the abovediscussed points using something which is a combination of both.
Having a proper step by step guide will help employees avoid further damages. If the dosing interval is the same as the half-life of the drug, the loading dose should be twice the maintenance dose (i.e. "Pharmacodynamic properties of antibiotics: application to drug monitoring and dosage regimen design." "Continuous versus intermittent infusion of vancomycin in severe staphylococcal infections: prospective multicenter randomized study." Increased renal clearance (hyperdynamic states, eg. Thompson, Gary A. ", "Continuous versus intermittent infusion of vancomycin in severe staphylococcal infections: prospective multicenter randomized study. For drugs not given IV, these doses need to be divided by the bioavailability.
 One or more doses higher than the maintenance dose can be given together at the beginning of therapy with a loading dose.. Researchers continue to find and test new drugs. "Pharmacokinetic-based design and modification of dosage regimens." This is probably a waste of time if it is happening on the night before the exam.
In pharmacokinetics, a maintenance dose is the maintenance rate [mg/h] of drug administration equal to the rate of elimination at steady state. When different medicines are used it is called switch maintenance. There are no professional guidelines and therapy may last only a couple months or several years.
early sepsis), Increased maintenance dose or dose rate; also possibly dencreased dosing interval, Decreased hepatic clearance (decreased hepatic blood flow or inhibited liver enzyme function), Oral loading dose would need to be decreased to accommodate for the decreased first pass metabolism, Increased hepatic clearance (increased hepatic blood flow or hepatic parenchymal clearance). Today’s arsenal of chemotherapy agents includes many different classes of medicines. Advanced drug delivery reviews 77 (2014): 3-11. Maintenance chemo stands in contrast to consolidation chemotherapy. The major factors involved in deciding on how often one should dose the drugs should be determined by the following factors: The longer the dosing interval in proportion to half-life, the greater the fluctuation of concentration between doses. The peak level is very high, and the trough is very low in once daily dosing. The graph comes from Wysocki et al (2000); they targeted trough levels of 15mg/L and maintenance levels of 20-25mg/L. It must be ensure that drugs which are stored remain preserved during their storage.
This is not an all-inclusive list of maintenance medications and it is subject to change at least quarterly or more frequently at Express Scripts Canadas discretion. "Dosage regimen design: a pharmacokinetic approach." One could do worse than the 1982 Dosage regimen design by DeVane and Jusko. Oral loading dose would need to be increased to accommodate for the increased first pass metabolism, Decreased protein binding (due to lower levels of protein). 3. "Pharmacokinetics of theophylline; application to adjustment of the clinical dose of aminophylline." Blot, Stijn I., Federico Pea, and Jeffrey Lipman. However, in the spirit of encouraging bad behaviour, some alternative peer-reviewed resources can be suggested. This time could be filled with a drug holiday. Vancomycin and β-lactams: examples of drugs which are subject to increased renal clearance in the context of hyperdynamic circulatory states, for example in early sepsis. Steady state and the therapeutic effect are achieved much sooner.
"Cp vs time - iv infusion with loading dose", https://en.wikipedia.org/w/index.php?title=Maintenance_dose&oldid=919321609, Creative Commons Attribution-ShareAlike License, This page was last edited on 3 October 2019, at 02:33. The drugs are stocked in containers, such as boxes and on flexible racks and shelves etc.
Williams, Roger L. "Dosage regimen design: pharmacodynamic considerations." ", Pharmacokinetics of theophylline; application to adjustment of the clinical dose of aminophylline. Question 10 from the first paper of 2009 asked, "What factors may affect these values [calculations involved in determining the loading dose and maintenance dose for an intravenous infusion] in the critically ill? For patients with advanced cancer in which primary chemotherapy treatment has not resulted in a remission, maintenance therapy can sometimes help extend lifespan. This is probably ok for a drug which is expected to have some sort of long-term effect, but if you are waiting for something critically and immediately important (pain relief, control of AF etc) you probably can't afford to spend five days patiently watching the concentration increase. This chapter is vaguely relevant to parts from Section B(v) of the 2017 CICM Primary Syllabus, which expects the exam candidate to "explain the concepts of intravenous bolus and infusion kinetics". The steady state concentration is determined only by two major factors, the dose rate and the clearance rate. About Asthma, Maintenance: Asthma is an inflammatory disorder of the airways, characterized by periodic attacks of wheezing, shortness of breath, chest tightness, and coughing. Hormone therapy given after primary treatment could be considered maintenance therapy.
This is a graph of vancomycin concentrations, comparing intermittent dosing with continuous infusion. The following memorable illustrative examples should be committed to storage and then regurgitated upon the examiners: Previous chapter: First order, zero order and non-linear elimination kinetics, Next chapter: Plasma drug concentration measurements in clinical practice. Reuning, R. H., R. A. Sams, and R. E. Notari. Or it could be used for maintenance therapy. The American Society of Clinical Oncology webpage on this topic expresses a concern that giving a patient maintenance therapy may forestall the psychological shift from patient to survivor. A loading dose is most useful for drugs that are eliminated from the body relatively slowly.