الحاجه أم ياسين عايزه اريثروسين ....؟ case 6

السلام عليكم

الحمد لله الذي هدانا لهذا وما كنا لنهتدي لولا أن هدانا الله

جزاك الله خيرا أيها المدير على هذه الحالة الرائعة حقا

فقد فتحت لي أفاقا جديدة وهامة

إن هذه الحالة تتمحور حول مجموعة هامة من الإنزيمات

The cytochrome P450 system

وهذه الإنزيمات تستحق فعلا أن نتحدث عنها قليلا في مساهمة قادمة

لأنها عماد التفاعلات الدوائية

[center]Erythromycin is metabolized by and inhibits the cytochrome P450 system,particularly the CYP3A4 isozyme, which can cause it to affect the metabolism of many different drugs



Macrolides that may significantly inhibit CYP450 3A4 include clarithromycin and erythromycin.

Azithromycin is generally believed to have little, if any,
effect on CYP450 3A4


So Erythromycin interferes with the metabolism of colchicine, this
can lead to increased blood levels and potential toxicity

The toxic effects of colchicine can include
Agranulocytosis
GIT: vomiting and diarrhea
Renal failure

The interaction betwenn erythromycin and colchicine is classified
as major drug interaction(potentially dangerous


On the other hand,Isoptin, a popular trade name for verapamil,is
a potent inhibitor of CYP450 3A4, leading to increased blood levels
of Erythromycin

This increased levels of Eryhtromycin will lead to prolongation
of the QT interval, and can culminate in life-threatening
cardiac arrhythmia(Torsade de pointes)

Do you remember Terfenadine ??

It was mentioned in previous case posted by the admin

It also predispodes to prolongation of the QT interval and consequently
the same dangerous result

Torsade de pointes

Many druds predispose to this dangerous rhythm
and many of them were withdrawn from the markets worlwide

including terfenadine itself

We will discuss these drugs in due course