Outcomes Research Consortium - Red Hair and Anesthesia

Red Hair and Anesthesia

150 years after their discovery, how anesthetic gases work remains unknown. They work well in all mammals, rodents, insects, worms, fish, bacteria, and even plants. The dose required in various species doesn’t differ much from the dose in humans. In non-human species, there are distinct genetic characteristics that clearly influence anesthetic sensitivity. But until recently, no genetic factors were known to influence anesthetic requirement in humans. In a series of studies, Consortium members have shown that the effective dose of anesthetic gases is about 20% greater in natural redheads than in people with other hair colors. Red hair results from a mutation of the melanocortin-1 receptor. The Consortium’s results thus indicate that something about this receptor influences anesthetic action. Red hair was the first phenotype (physically apparent characteristics linked to a genetic mutation) linked to anesthetic requirement in humans, and remains the only one. Consortium research on red hair and anesthetic requirement has been covered by the San Francisco Examiner, The Globe and Mail, and Readers Digest. In further research, members of the Consortium found that redheads are resistant to local anesthetics. Consequently, they are more likely to suffer pain during dental procedures — and are therefore reluctant to receive needed dental care. Consortium research on red hair and dental avoidance has been covered by Macleans, the Boston Herald, and The New York Times.