Clark's rule is a
medical term
Medicine is the science and practice of caring for patients, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care pract ...
referring to a mathematical formula used to calculate the proper dosage of
medicine
Medicine is the science and Praxis (process), practice of caring for patients, managing the Medical diagnosis, diagnosis, prognosis, Preventive medicine, prevention, therapy, treatment, Palliative care, palliation of their injury or disease, ...
for children aged 2–17 based on the weight of the patient and the appropriate adult dose.
The formula was named after
Cecil Belfield Clarke (1894–1970), a
Barbadian physician who practiced throughout the UK, the West Indies and Ghana.
Overview
The procedure is to take the child's
weight
In science and engineering, the weight of an object is a quantity associated with the gravitational force exerted on the object by other objects in its environment, although there is some variation and debate as to the exact definition.
Some sta ...
in
pounds, divide by 150 lb, and multiply the fractional result by the adult dose to find the equivalent child dosage. For example, if an adult dose of medication calls for 30 mg and the child weighs 30 lb, divide the weight by 150 (30/150) to obtain 1/5 and multiply 1/5 times 30 mg to get 6 mg.
Though it is more common for physicians to use medications that have suggested manufacturer's doses for children, familiarity of Clark's rule is used as an additional layer of protection against potentially deadly
medication errors
A medical error is a preventable adverse effect of care ("iatrogenesis"), whether or not it is evident or harmful to the patient. This might include an inaccurate or incomplete diagnosis or treatment of a disease, injury, syndrome, behavior, i ...
in clinical practice.
Fried's rule
Similar to Clark's rule is ', by which the formula is modified to be used for infants.
The formula is nearly identical, except with the child's weight replaced by the infant's age in months.
Fried's rule was named after
Kalman Fried (1914–1999), an Israeli geneticist and pediatrician who developed his own formula while treating and observing children at the
Hebrew University of Jerusalem
The Hebrew University of Jerusalem (HUJI; ) is an Israeli public university, public research university based in Jerusalem. Co-founded by Albert Einstein and Chaim Weizmann in July 1918, the public university officially opened on 1 April 1925. ...
-affiliated
Hadassah Medical Center
Hadassah Medical Center () is an Israeli medical organization established in 1934 that operates two university hospitals in Jerusalem (one in Ein Karem and one in Mount Scopus) as well as schools of medicine, dentistry, nursing, and pharmacology ...
in the 1960s. Fried though was more renowned as a
geneticist
A geneticist is a biologist or physician who studies genetics, the science of genes, heredity, and variation of organisms. A geneticist can be employed as a scientist or a lecturer. Geneticists may perform general research on genetic process ...
rather than a
pediatrician
Pediatrics (American English) also spelled paediatrics (British English), is the branch of medicine that involves the medical care of infants, children, adolescents, and young adults. In the United Kingdom, pediatrics covers many of their youth ...
.
Young's rule
The earlier '
for calculating the correct dose of medicine for a child is similar: it states that the child dosage is equal to the adult dosage multiplied by the child's age in years, divided by the sum of 12 plus the child's age.
Young's rule was named after
Thomas Young (1773–1829), an English polymath, physician and physicist.
References
External links
Clinical Calculation(5th Ed) Ch 12: Pediatric Dosage
Year of introduction missing
Clinical pharmacology
Rules of thumb
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