The four most common equations used to calculate the BSA are included in this calculator. Journal of Oncology Practice / American Society of Clinical OncologyFreireich, E. J., Gehan, E. A., Rall, D. P., Schmidt, L. H., & Skipper, H. E. (1966).
Pinkel, D. (1958). The BSA is frequently used in determining the dosage of medications with a narrow therapeutic index, such as chemotherapeutic agents. For example, if you must administer 1 L (1,000 mL) of fluid over 4 hours, use the first formula to calculate the flow rate, like so: flow rate (mL/hr) = total volume (mL) ÷ infusion time (hr) flow rate (mL/hr) = 1,000 ÷ 4 flow rate (mL/hr) = 250 Chemotherapy Dosing Part I: Scientific Basis for Current Practice and Use of Body Surface Area. Experiments with small animals identify the lethal dose, which is probably going to be about the same (scaling for body size) as the lethal dose for humans. Some practitioners also believe patient adherence is better when fixed doses are prescribed rather than, for example, taking two large and one small tablet per day (Felici, Verweij, & Sparreboom, 2002).The idea behind BSA was that elimination of the drug was by the kidneys and liver and their capacity scaled with body surface area. (The early BSA advocates assumed that kidney removal rate was roughly proportional to surface area, and that turned out not to be true.) Patient response is measured as dosing is increased to get an idea of how high a dose a human can be given before side effects become intolerable.BSA is used for most old-style cytotoxic drugs, but things are different for targeted therapies. If you want to calculate the dose of a medication, you need to use the following equation: dose = weight * dosage. Body-surface area-based chemotherapy dosing: Appropriate in the 21st century? Dosing strategies for anticancer drugs: the good, the bad and body-surface area. The epidemic of obesity means many cancer patients are overweight. Doctors and scientists looked for a better way – alternatives that accounted for factors affecting drug exposure and clearance such as liver and kidney function (Beumer, Chu, & Salamone, 2012).Measures related to body size such as body surface area, height and weight are used to calculate the required doses, as they theoretically are a way to tailor doses according to body size and ability to clear the drug.Most drugs doctors prescribe are administered as in fixed doses. Dose size is one of the questions animal trials and clinical trials set out to answer. 1989;7:1748-1756. That is where dosing calculations start from, and for decades the “body surface area” of the patient has been an important factor in calculating doses.Body surface area (BSA) is one way of measuring how large a person is. These formulas all give slightly different results.
You can usually find this number on the medicament box or on the prescription. Additional factors that should be assessed include: previous exposure to chemotherapy or radiotherapy, and overall health status. (2012). LD10 is the dose that kills 10 percent of animals (LD means “lethal dose”). It is not a matter of scaling up directly with the body mass, as an obese person’s extra weight is disproportionately adipose tissue. (2012). To employ this formula, doctors must estimate the patient’s glomerular filtration rate (GFR) in the kidneys – a measure of how fast the patient’s body removes the chemotherapy agent in tbe blood to the urine. (2006). Carboplatin dosage: prospective evaluation of a simple formula based on renal function. The idea is that the patient answers questions or enters data through an internet intake system.
Body surface area correlates with the capacity of the kidneys and liver, which are the organs that detoxify and eliminate poisons. This BSA calculator works as a chemotherapy dose calculator also and will give you the total dose of chemotherapy drug with one single click of the mouse. This system works because most drugs for other maladies have a wide therapeutic index and less interpatient pharmacokinetic variability than oncology drugs do.
DuBois and DuBois. It is very important that you input an accurate result; Dosage is the prescribed amount of drug in mg per kg of body weight. Miller, A.
Body Surface Area in Dosing Anticancer Agents: Scratch the Surface! Hempel, G., & Boos, J.
Halls, MD . but I'm having second thoughts now.