TABLE 2.

Recommendations for dose adjustment for different CYP2C19 phenotypes.

First author year	Study design	Sample size	Phenotype	Recommendations for dose adjustment
Zubiaur et al. (2021)	prospective observational study	106	UMs	3 times the standard dose
			RMs	2 times the standard dose
			NMs	the standard dose
			IMs	0.5 times the standard dose
			PMs	0.25 times the standard dose
Tanaka et al. (2020)	prospective observational study	19	IMs	Reduce the initial maintenance dose
			PMs
Blanco-Dorado et al. (2020)	prospective observational study	78	RMs	Increase the initial maintenance dose
			UMs
Li et al. (2020)	prospective observational study	93	RMs	PO 400 mg, twice a day
			NMs	PO 400 mg, twice a day
			IMs	PO 200 mg, twice a day
Hicks et al. (2020)	prospective observational study	202	UMs	VRZ is recommended to be avoided
			RMs	PO 300 mg, twice a day
			NMs, IMs, PMs	PO 200 mg, twice a day
Miao et al. (2019)	retrospective cohort study	105	NMs	the standard dose
			IMs	1.64 times the standard dose
			PMs	2.61 times the standard dose
Lin et al. (2018)	prospective observational study	105	RMs	IV 300 mg, twice a day
			IMs	IV 200 mg/Oral 350 mg, twice a day
			PMs	IV 150 mg/Oral 250 mg, twice a day
PharmGKB (2017)	NA	NA	UMs	1.5 times the standard dose
			IMs	the standard dose
			PMs	0.5 times the standard dose
Lamoureux et al. (2016)	retrospective study	35	UMs	IV 6.75 mg/kg, twice a day
			RMs	IV 3.94 mg/kg, twice a day
			NMs	IV 2.57 mg/kg, twice a day
Wang et al. (2014b)	prospective observational study	144	PMs	PO 200 mg, twice a day
			non-PMs	IV 200 mg/PO 300 mg, twice a day

UMs, CYP2C19 ultra-rapid metabolizers; RMs, CYP2C19 rapid metabolizers; NMs, CYP2C19 normal metabolizers; IMs, CYP2C19 intermediate metabolizers; PMs, CYP2C19 poor metabolizers; PO, oral administration; IV, intravenous injection; NA, not applicable.