Table 1. . Traumatic brain injury drug–gene pairs.

Medication	Use(s)	Gene	Variant	Association	Clinical recommendation
Phenytoin	Post-traumatic seizures, post-traumatic epilepsy	HLA-B	*15:02	Increased risk for SCAR	Avoid
		CYP2C9	Intermediate/poor metabolizers	Decreased systemic clearance	Use lower dose
Ketamine	Sedation, analgesia	CYP2B6	*6/*6	Decreased systemic clearance	N/A†
Midazolam	Sedation	CYP3A5	*3	Decreased systemic clearance	N/A†
Fentanyl	Sedation, analgesia	CYP3A5	*3	Decreased systemic clearance	N/A†
		OPRM1	rs1799971 (GG)	Decreased sensitivity	N/A†
		ABCB1	rs1045642 (TT)	Increased brain/CSF concentrations	N/A†
Morphine	Sedation, analgesia	ABCB1	rs1045642 (TT)	Increased brain/CSF concentrations	N/A†
		OPRM1	rs1799971 (GG)	Decreased sensitivity	N/A†
Citalopram, escitalopram, sertraline	Post-traumatic depression	CYP2C19	Poor metabolizers	Decreased systemic clearance	Decrease dose
			Ultra-rapid metabolizers	Increased systemic clearance	Use alternative agent‡
Paroxetine		CYP2D6	Ultra-rapid metabolizers	Increased systemic clearance	Use alternative agent
			Poor metabolizers	Decreased systemic clearance	Use alternative agent
Fluvoxamine					Decrease dose

^†No specific clinical guidance available.

^‡Does not apply to sertraline.

CSF: Cerebrospinal fluid; N/A: Not available or defined; SCAR: Severe cutaneous adverse reaction.