TUNA, look what I found in the ZONA thread!!!
"To: Dauntless (850 )
From: Tunica Albuginea Saturday, Nov 22 1997 11:50AM EST
Reply #867 of 873
Dauntless, I am back at the Zona thread today because the Viuvs thread is closed this AM: Vivus longs are taking a well deserved
rest and enjoying the recent Vivus run up on the FDA's approval of their manufacturing complex in NJ.
And so here I am; willoing ( and able ) to answer any and all of your questions:
For thwe newcomers the case involves a case of Pheochromocytoma I treated several years ago with IV phentolamine
in the operating room while her tumor was being taken out.Phentolamine was given to control her pre-operative BO of ~ 220/120.
Dauntless is dauntlessly asking, and Tuna is .... dauntlessly ...responding:
Q:- What was the concentration & infusion rate of the phentolamine drip - i.e. - were you pushing it in faster than the patient could eliminate it?
A:Phentolamine was given as I have always given it ( for extravasated Dopamine,or for abdominal aortic distal dissection afecting the renal arteries, etrc,) as per our protocol at the medical
centre: 60mg/100 cc of normal saline, which comes to 0.6 mg/ml;
we start the solution 0.1 mg / minute ; the effect is immediate; it lasts
3 - 10 minutes. the medication is then titrated rapidly upwards every
3-6 min under direct intraarterial continuous monitoring through an intraarterial line.The patient also had a baloon - tipped pulmonary
flotation catheter ( Swan-Ganz ) to monitor intravascular volume.
It is a weel known fact that patients with pheochromocytoma are
EXTREMELY vasoconstricted from the excess adrenaline and thus are INTRAVASCULARLY VLOUME DEPLETED; thus the aim was to also infuse fluid in to maintain a pulmonary capillary wedge pressure of around 15 - 20 mmHg.
Anestesologist and I were jointly discussing the hemodynamic data
and jointly deciding on infusion rates:
You have to be very carefull how you handle these tumors: at the slightest otuch your are SQEEZING ADRENALINE into their system and their blood pressure sky rockets within minutes: you then need to increase the IV rate.
When you have finally ISOLATED the tumor and are now ready to ligate the vessels THAT TIE IT TO THE PATIENT then you
FIRST TURN PHENTOLAMINE OFF, because when you tie the vessels off there is NO MORE ADRENALINE being pumped into the patient and THE BLOOD PRESSURE will D R O P drammatically so you have to have phentolamine off first or you are going to put the patient into shock and kill her.
Q:- What other drugs/anesthetics were being administered at the same time?
A:the patient was given inhalational anesthesia by the chief of the Anesthesia Dept at the Medical center.A combination of Nitous Oxide, Isofluorene, oxygen with Pavulon as a muscle relaxant is what was popular at that time ( and can be used even today, although there are some even better products available today ).She was a little
tachycardic and small doses of inderal were given to keep her heart rate ~ 70-80. Thaat did not affect her BP when we gave it.
She was on NO other drugs since she was an otherwise helthy 33 year old.
Q:- Do you recall what the blood levels of phentolamine were during your single bad experience with IV administration?
A: With all due respect Dauntless, this is a silly question, GG.::
--We don't measure phentolamine levels when you have a drug whose halg life is 5 minutes.
--The technology to measure this is not used clinically.( By the way Dauntleess, an aside question: do you foresee having to mesure patient's phentolamine blood levels who are on it for ED therapy?That I think will kill all the fun right there!! ).
--By the time we got the level back, ( 3 days later, gg, the patient would be edead or recovering!!!
Also Dauntless, for accuracy's sake this was NOT a SINGLE horrific episode of low BP .The patient's blood pressure was dancing up and down like a yo- yo all through the 1 1/2 hour that we were trying to isolate the tumor.The operation was slow ecactly because we were trying to keep her BP normal;
Q: " - How did the blood levels compare with those seen in the patients enrolled in the studies receiving oral phentolamine?".
A: My my, ANOTHER silly qustion Dauntlesss; we must be collecting them today;
a} again, we do not do phentolamine levels in clinical practice.
b} -THERE WAS NO ORAL PHENTOLAMINE GIVEN AT THAT TIME FOR ANY REASON, GGGGG
-THERE WAS NO ORAL PHENTOLAMINE GIVEN AT THAT TIME FOR ANY REASON, GGGGG
-THERE WAS NO ORAL PHENTOLAMINE GIVEN AT THAT TIME FOR ANY REASON, GGGGG
-THERE WAS NO ORAL PHENTOLAMINE GIVEN AT THAT TIME FOR ANY REASON, GGGGG
BECAUSE
BECAUSE
BECAUSE
- the half life is too short ( 5 min ).
-that means you have to give a very large amount orally to have enough drug around to get any effect.
-however, because the toxic/therapeutic ratio on this drug is so small, giving large oral doses will kill you through shock.
c}the studies comparing IV with oral phantolamine where done
OVER 40 ( Read, F O R T Y } YEARS ago Dauntless.
They are no longer even referenced in the current pharmacology index!!!!
The studies showed that oral phentolamine used to treat hypertension was unsafe and ineffective and thus oral phentolamine was D U M P E D !!! ( as in dumped ).
Q: " - Did this patient have any diseases or conditions that might have contributed to the BP swings? "
A: No. She was a helthy 33 year old.
I hope this very informative question and answer session on Vasomax will be usefull to you Dauntless and lead you to the only correct next cours of action: Dump th estock.
< GGGGGGGGGGGGGGGG >
( More in the future on this subject from brother Asensio for those interested to hear more on the matter . ggg. ).
TA |
