. 2010 Jan 20;25(4):305–309. doi: 10.1007/s11606-009-1225-0

Table 1.

Potential Risk Factors in Methadone Deaths

Potential risk factors for respiratory depression	Potential risk factors for TdP
Advancing age⁵^,³²	Female gender³⁰
Medically compromised³⁴	Electrolyte imbalance²⁷^,²⁸
Liver or pulmonary pathology⁸	Liver or cardiac pathology⁸
Sleep apnea³³	Unexplained syncope or seizures²⁹
Polysubstance use¹⁹^,²¹	Other drug and medication use, especially those that impact QTc or inhibit CYP 3A428²⁸^,³⁰
Opioid-naïve/low tolerance³²	Prolonged QTc²⁴
High doses of methadone³⁴	High doses of methadone²⁷^,²⁸
Rapid titration of methadone dosing³⁴