Big butts hinder drug injections

Fatter rear ends are causing many drug injections to miss their mark, requiring longer needles to reach buttock muscle, researchers say.

Standard-sized needles failed to reach the buttock muscle in 23 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, researcher 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," she said.

"The amount of fat tissue overlying the muscles exceeds the length of the needles commonly used for these injections."

The 25 men and 25 women studied at the Irish hospital ranged from 21 to 87 years old.

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 per cent of US adults are overweight or obese.

- REUTERS