Table 2.

Pharmacogenomic liability of medications commonly prescribed during pregnancy

Medication Class	Medication	Biomarker	Associated pharmacogenetic liability
Antimicrobials	Nitrofurantoina	Gluocose-6-phosphatedhydrogenasedeficiency) G6PD	Hemolytic anemia risk
Antidepressants	Citalopram/escitalopramb,(50)	CYP2C19	CYP2C19 ultrarapid metabolizers have lower plasma concentrations, increasing likelihood of treatment failure.
			CYP2C19 poor metabolizers have higher plasma concentrations; consider a 50% reduction of starting dose.
	Paroxetineb,(50)	CYP2D6	CYP2D6 ultrarapid metabolizers have lower plasma levels, increasing the probability of treatment failure.
			CYP2D6 Intermediate and poor metabolizers may have higher plasma concentrations and an increased risk of side effects. Consider a 50% reduction of starting dose in poor metabolizers.
Antiepileptics	Carbamazepinea	HLA	HLA-B*15:02 is associated with greater risk of Stevens-Johnson Syndrome (SJS) and toxic epidermal necrolysis (TEN)
			HLA-A*31:01 is associated with greater risk of maculopapular exanthema, drug reaction with eosinophilia, and SJS/TEN
	Oxcarbazepinea	HLA	HLA-B*15:02 is associated with greater risk of Stevens-Johnson Syndrome (SJS) and toxic epidermal necrolysis (TEN)
Antihypertensives	Metoprolola	CYP2D6	Poor metabolizers and extensive metabolizers who concomitantly use CYP2D6 inhibiting drugs will have increased metoprolol levels
Gastroenterology	Metoclopramidea	CYP2D6	CYP2D6 Poor metabolizers at are at potentially increased risk of dystonic and other adverse reactions. Lower maximum daily dose recommended in CYP2D6 metabolizers.
	Omeprazolea	CYP2C19	Systemic exposure to omeprazole varies with patient’s metabolism status at CYP2C19
	Ondansteronb,(44)	CYP2D6	Increased metabolism in CYP2D6 ultrarapid metabolizers, associated with decreased response to medication
Opioids	Codeinea,b,(12)	CYP2D6	CYP2D6 Ultra-rapid metabolizers can have higher than expected serum morphine levels, leading to respiratory depression. Ultra-rapid metabolizers may have higher levels of morphine in breastmilk, leading to infant respiratory depression.
	Codeinea	UGTB7*2	Infants who are breastfeeding and have the UGTB7*2 genotype have potentially reduced activity. In combination with a mother who is an ultrarapid metabolizer, this may lead to toxicity of morphine in the infant.

^aFDA Pharmacogenomic biomarkers in drug labeling: https://www.fda.gov/Drugs/ScienceResearch/ucm572698.htm

^bCPIC guidelines: https://cpicpgx.org/guidelines/

⁽ⁿ⁾Correlates to reference number in bibliography