Tue Nov 29, 2005 8:09 AM ET 
CHICAGO
(Reuters) - Fatter rear ends are causing many drug injections to miss
their mark, requiring longer needles to reach buttock muscle,
researchers said on Monday.
Standard-sized needles failed to
reach the buttock muscle in 23 out of 25 women whose rears were
examined after what was supposed to be an intramuscular injection of a
drug.
Two-thirds of the 50 patients in the study did not receive
the full dosage of the drug, which instead lodged in the fat tissue of
their buttocks, researchers from The Adelaide and Meath Hospital in
Dublin said in a presentation to the annual meeting of the Radiological
Society of North America.
Besides patients receiving less than
the correct drug dosage, medications that remain lodged in fat can
cause infection or irritation, researchers Victoria Chan said.
"There
is no question that obesity is the underlying cause. We have identified
a new problem related, in part, to the increasing amount of fat in
patients' buttocks," Chan said.
"The amount of fat tissue overlying the muscles exceeds the length of the needles commonly used for these injections," she said.
The 25 men and 25 women studied at the Irish hospital ranged in age from 21 to 87.
The
buttocks are a good place for intramuscular injections because there
are relatively few major blood vessels, nerves and bones that can be
damaged by a needle. Plentiful smaller blood vessels found in muscle
carry the drug to the rest of the body, while fat tissue contains
relatively few blood vessels.
Obesity affects more than 300
million people worldwide and is based on a measure of height versus
weight that produces a body mass index above 30. An estimated 65
percent of U.S. adults are overweight or obese.
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