Pharmacogenetics to Avoid Loss of Hearing (PALOH) trial: a protocol for a prospective observational implementation trial oleh Richard Body, Mark A Turner, William G Newman, John Henry McDermott, Gino Miele, Peter Roberts, Fiona Ulph, Rhona MacLeod, Shaun Ainsworth, Rachel Mahood, Duncan Stoddard, Ajit Mahaveer, Rachel Corry, Julia Garlick, Laura Kemp, Karen Harvey, Nicola Booth