L2 ( CYP 2C19 ) Flashcards
True or false?
CYP 2C19 enzyme responsible for metabolism of the following drugs :
1️⃣ Proton pump inhibitors (lansoprazole, omeprazole, pantoprazole)
2️⃣ Clopidogrel
3️⃣ Anxiolytic drug: Diazepam
4️⃣ Antimalarial: proguanil
5️⃣ Antidepressants (citalopram, escitalopram, imipramine, amitriptyline and clomipramine)
True ✅
Complete the sentence:
The principal defective alleles for the CYP2C19 genetic polymorphism that resulting in inactive enzyme are….
1️⃣ CYP2C192 (c.19154G>A, aberrant splice site) in exon 5
2️⃣ CYP2C193(c.17948G>A, premature stop codon) in exon 2
3️⃣ CYP2C194 (a mutation in the initiation codon)
4️⃣ CYP2C197 (a splice mutation in intron 5)
Complete the sentence:
PMs ( poor metabolizer )can be defined as …..
individuals carrying two defective CYP2C19 alleles.
True or false?
The clinical relevance of the CYP2C19 polymorphism has been demonstrated
for proton pump inhibitors and clopidogrel.
True ✅
True or false?
PMs ( poor metabolizer ) for the CYP2C19 polymorphism showed up to a 10-fold increase in the area under the curve (AUC) of omeprazole compared with EMs ( Extensive metabolizer) .
True ✅
True or false?
The presence of a defective CYP2C19 allele has been associated with improved Helicobacter pylori cure rates after
1️⃣ dual therapy (omeprazole and amoxicillin)
2️⃣ triple therapy (omeprazole or lansoprazole, clarithromycin, and
amoxicillin)
True ✅
True or false?
The cure rate achieved with dual therapy was much higher (100%) in PMs ( poor metabolizer) compared with 60% and 29% in EMs ( Extensive metabolizer) .
True ✅
Note :
These differences likely reflect the higher achievable intragastric pH in
the PM group.
True or false?
CYP2C19 PM genotype is beneficial in the treatment of gastric ulcer and gastroesophageal reflux disease due to the impaired metabolism of PPIs and therefore higher plasma concentrations of the PPIs in individuals having the CYP2C19 PM genotype.
True ✅
Complete the sentence:
Clopidogrel is a prodrug requires conversion to it’s active form via …
CYP2C19
True or false?
IMs (imitated metabolizer) and PMs ( poor metabolizer) of CYP2C19 may have reduced response to the antiplatelet agent clopidogrel and potentially require higher doses or alternative
antiplatelet therapy for better clinical outcomes.
True ✅
True or false?
In IMs ( imitated metabolizer )and PMs (poor metabolizer) , usual doses of clopidogrel are less effective at inhibiting platelet aggregation and preventing cardiovascular events than in EMs ( effective metabolizer)
True ✅
Complete the sentence:
Diazepam is demethylated by ….
CYP2C19
True or false?
The plasma half-life of diazepam is about 4-fold longer in individuals forPM genotypes than in individuals homozygous for the wild-type CYP2C19*1.
True ✅
True or false?
Physicians routinely prescribe a lower dose of diazepam for Asian patients,which is attributed to the high frequency of CYP2C19*2 and *3 in Asians.
True ✅
True or false?
Toxic doses of diazepam may occur in PMs and therefore more care would be required for the decision of diazepam dose, particularly in Asians.
True ✅
