Research has indicated that individuals with red hair exhibit distinct responses to various anesthetic agents, partly due to genetic factors associated with their hair color. A notable genetic variant in red-haired individuals is the mutation in the melanocortin-1 receptor (MC1R) gene, which has been correlated with altered sensitivity to anesthesia and pain perception (Chua et al., 2004; Myles et al., 2012; Augustinsson et al., 2024).
Studies have demonstrated that red-haired individuals may require higher doses of inhaled anesthetics, such as desflurane and isoflurane, to achieve comparable levels of anesthesia when compared to those with darker hair (Meretsky et al., 2024; Myles et al., 2012). This increased requirement has been documented across multiple studies, including a comprehensive review that specifically noted the greater anesthetic potency needed for red-haired patients during general anesthesia (Meretsky et al., 2024). Furthermore, these subjects show heightened sensitivity to thermal pain, which implies that their pain threshold may be lower, contributing to their altered anesthetic requirements (Liem et al., 2005; Gradwohl et al., 2015).
The findings from Chua et al. suggest that midazolam, a commonly used sedative, results in significantly less sedation in red-haired individuals compared to those with other hair colors (Chua et al., 2004; Gradwohl et al., 2015). This phenomenon indicates a potential resistance to certain anesthetic agents, underscoring the need for anesthesiologists to consider hair color as a variable in anesthetic management. Intraoperative awareness, defined as the patient’s awareness of their surroundings during anesthesia, appears to be more prevalent among red-haired patients, reinforcing the necessity for careful monitoring and tailored anesthetic approaches (Gradwohl et al., 2015; Sessler, 2015).
Moreover, local anesthetics, notably lidocaine, have shown reduced efficacy in red-haired individuals, leading to potential challenges in achieving adequate analgesia in dental procedures or other settings requiring local anesthesia (Liem et al., 2005; Droll et al., 2012). This resistance to local anesthetics could be a contributing factor to the anxiety some individuals with red hair experience regarding dental care (Binkley et al., 2009).
In summary, the evidence strongly supports the notion that red-haired individuals display resistance or altered responses to various anesthetic agents, necessitating an individualized approach in their anesthetic management to ensure effective and safe outcomes.
References:
- Augustinsson, A., Franze, E., Almqvist, M., Stomberg, M., Sjöberg, C., & Jildenstål, P. (2024). Red-haired people’s altered responsiveness to pain, analgesics, and hypnotics: myth or fact?—a narrative review. Journal of Personalized Medicine, 14(6), 583.
https://doi.org/10.3390/jpm14060583
- Binkley, C., Beacham, A., Neace, W., Gregg, R., Liem, E., & Sessler, D. (2009). Genetic variations associated with red hair color and fear of dental pain, anxiety regarding dental care and avoidance of dental care. The Journal of the American Dental Association, 140(7), 896-905.
https://doi.org/10.14219/jada.archive.2009.0283
- Chua, M., Tsueda, K., & Doufas, A. (2004). Midazolam causes less sedation in volunteers with red hair. Canadian Journal of Anesthesia/Journal Canadien D Anesthésie, 51(1), 25-30.
https://doi.org/10.1007/bf03018542
- Droll, B., Drum, M., Nusstein, J., Reader, A., & Beck, M. (2012). Anesthetic efficacy of the inferior alveolar nerve block in red-haired women. Journal of Endodontics, 38(12), 1564-1569.
https://doi.org/10.1016/j.joen.2012.08.014
- Gradwohl, S., Aranake, A., Abdallah, A., McNair, P., Lin, N., Fritz, B., … & Avidan, M. (2015). Intraoperative awareness risk, anesthetic sensitivity, and anesthetic management for patients with natural red hair: a matched cohort study. Canadian Journal of Anesthesia/Journal Canadien D Anesthésie, 62(4), 345-355.
https://doi.org/10.1007/s12630-014-0305-8
- Liem, E., Joiner, T., Tsueda, K., & Sessler, D. (2005). Increased sensitivity to thermal pain and reduced subcutaneous lidocaine efficacy in redheads. Anesthesiology, 102(3), 509-514.
https://doi.org/10.1097/00000542-200503000-00006
- Meretsky, C., Plitt, V., Friday, B., Schiuma, A., & Ajebli, M. (2024). A comparative analysis of the efficacy of local anesthetics and systemic anesthetics in the red-headed versus non-red-headed patient population: a comprehensive review. Cureus.
https://doi.org/10.7759/cureus.61797
- Myles, P., Buchanan, F., & Bain, C. (2012). The effect of hair colour on anaesthetic requirements and recovery time after surgery. Anaesthesia and Intensive Care, 40(4), 683-689.
https://doi.org/10.1177/0310057x1204000415
- Sessler, D. (2015). Red hair and anesthetic requirement. Canadian Journal of Anesthesia/Journal Canadien D Anesthésie, 62(4), 333-337.
https://doi.org/10.1007/s12630-015-0325-z