Glucose 6 phosphate dehydrogenase deficiency
Sixty drug labels that have PGx on risks and complications when the
drugs are used in glucose 6 phosphate dehydrogenase (G6PD)-deficient
patients. Fifty-three of these drugs have an actionable level of
information (such as contraindicated in patients with G6PD deficiency),
three have an informative level of information (e.g., succimer has been
used for the treatment of lead poisoning in five patients with G6PD
deficiency without adverse reactions; patients with a known history of
G6PD deficiency was excluded from some clinical trials; or patients with
a known history of G6PD deficiency was excluded from some clinical
trials), and two have testing required level of information (tafenoquine
and pegloticase) for all agencies. The labels for primaquine labels were
inconsistent: the FDA-approved drug label for primaquine states that
G6PD testing should be performed before using the drug and that the drug
should not be prescribed for patients with severe G6PD deficiency.
However, the HCSC-approved product monograph information level was
actionable for primaquine and states that caution should be exercised
while using the drugs in individuals with G6PD deficiency due to the
risk of hemolytic anemia, which we assume is based on the previous
testing. Similarly the information levels for rasburicase are also
variable: the FDA-approved label has and testing required and states
that patients at higher risk for G6PD deficiency, such as those of
African or Mediterranean ancestry, should be screened prior to starting
treatment, because rasburicase is contraindicated in patients with G6PD
deficiency. The EMA-, Swissmedic-, and PMDA-approved labels were
actionable and stated that rasburicase is contraindicated in patients
with G6PD deficiency due to risk of hemolytic anemia, which we again
believe is based on the assumption that the patient would have the
information on G6PD status prior to drug use. The HCSC-approved label
level was testing recommended and states that patients at higher risk
for G6PD deficiency (e.g., those of African or Mediterranean ancestry)
be screened prior to starting treatment, due to the risk of severe
hemolytic anemia.
TMMDA had actionable information in 17 and informative information in
three of the drug labels. For seven of the drugs (ceftriaxone,
ciprofloxacin, glibenclamide, gliclazide, nitroglycerin,
sulfamethoxazole/trimethoprim, and vitamin C), the information in the
labels differs between the original and/or generic forms.