Red heads may require higher doses of local and systemic anaesthesia.

By Dr Manu Ayer Oct 24

A new study has found that individuals with red hair often require higher doses of local and systemic anaesthetics to achieve the same level of pain relief or sedation than people with other hair colour. (1)  This study was not based on new clinical data but based on a systematic review of a wide array of previous research published over the last two decades. 

The relationship between red hair and pain perception has been a subject of scientific enquiry since the early 2000s. Previous studies found that individuals with red hair, as well as those with the corresponding melanocortin-1 receptor (MC1R) mutations, exhibited a greater resistance to the effects of systemic and local anesthetics, and these observed disparities in anaesthesia sensitivity may be attributed to their genetic variations in the MC1R gene, a key determinant of hair and skin colour.

Previous studies have reported that red heads tend to have a greater fear of dental care compared to people with other hair colour, which may account for their need for higher doses of both for local and general anaesthetic agents. Additionally, some studies noted that red-haired patients were more sensitive to the side effects of certain anaesthetic drugs, necessitating more careful monitoring and dose adjustments. 

Whatever the explanation for these findings, clinicians should be aware of these potential idiosyncrasies when administering anaesthesia to red haired patients and consider adopting personalized approaches based on genetic and phenotypic factors. A thorough evaluation of a patient's hair colour and any known MC1R genotype could aid in the selection and dosage of anaesthetic agents, optimizing safety and effectiveness.

Enhancing our comprehension of the genetic and molecular underpinnings of anaesthesia sensitivity in this population could pave the way for more customized anaesthetic management approaches, ultimately improving patient outcomes and minimizing the risk of adverse events.

1) 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 2024 Meretsky et al. Cureus 16(6): e61797. DOI 10.7759/cureus.61797