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Dr. Bob is Robert Hsiung, MD,
[email protected]Shown: posts 1 to 12 of 12. This is the beginning of the thread.
Posted by ed_uk on January 3, 2005, at 21:11:48
To everyone who has ever taken an MAOI....
Did you pdoc provide any medication to take in the event of a hypertensive crisis?
What did you get? Nifedipine? Chlorpromazine?
Ed.
Posted by jerrympls on January 3, 2005, at 21:17:52
In reply to In the event of a hypertensive crisis....., posted by ed_uk on January 3, 2005, at 21:11:48
> To everyone who has ever taken an MAOI....
>
> Did you pdoc provide any medication to take in the event of a hypertensive crisis?
>
> What did you get? Nifedipine? Chlorpromazine?
>
> Ed.HI ed-
I think I got Nifedipine with the instructions being to break the capsule in my mouth then swallow, lie down and call 911. This was when I was on Nardil last December.
Jerry
Posted by sfy on January 3, 2005, at 21:21:04
In reply to In the event of a hypertensive crisis....., posted by ed_uk on January 3, 2005, at 21:11:48
> To everyone who has ever taken an MAOI....
>
> Did you pdoc provide any medication to take in the event of a hypertensive crisis?
>
> What did you get? Nifedipine? Chlorpromazine?
>
> Ed.Nifedipine. Always carried it around with me - never even reached for it in 2 years on Nardil.
Posted by ed_uk on January 3, 2005, at 22:06:49
In reply to Re: In the event of a hypertensive crisis....., posted by sfy on January 3, 2005, at 21:21:04
Oral phentolamine is no longer available in the US or the UK but it is used in some countries as a treatment for erectile dysfunction. I think oral phentolamine is available in Mexico and Brazil. IV phentolamine (Regitine) is still available in the UK for the treatment of hypertensive crises.
Has anyone been given oral phentolamine for use in case of a hypertensive crisis?
Ed.
Posted by Maxime on January 4, 2005, at 21:31:17
In reply to In the event of a hypertensive crisis....., posted by ed_uk on January 3, 2005, at 21:11:48
> To everyone who has ever taken an MAOI....
>
> Did you pdoc provide any medication to take in the event of a hypertensive crisis?
>
> What did you get? Nifedipine? Chlorpromazine?
>
> Ed.Chlorpromazine and I have been on Parnate for 2 years now and never needed to use it. I have eaten cheese, drank red wine. I have a high tolerance for tyramine. I take 80-100 mg of Parnate.
Max
Posted by ed_uk on January 4, 2005, at 21:50:11
In reply to Re: In the event of a hypertensive crisis....., posted by Maxime on January 4, 2005, at 21:31:17
Hi Max!
What dose of chlorpromazine does your pdoc suggest for a hypertensive crisis? 50mg? 100mg?
Ed.
Posted by Maxime on January 4, 2005, at 23:41:21
In reply to Re: In the event of a hypertensive crisis..... » Maxime, posted by ed_uk on January 4, 2005, at 21:50:11
> Hi Max!
>
> What dose of chlorpromazine does your pdoc suggest for a hypertensive crisis? 50mg? 100mg?
>
> Ed.Between 50 and 100 depending on how I feel. I would take 100. It is the dosage I have heard most people take. Luckily I have never to take it.
Maxime
Maxime
Posted by Maxime on January 4, 2005, at 23:44:19
In reply to Re: In the event of a hypertensive crisis..... » Maxime, posted by ed_uk on January 4, 2005, at 21:50:11
> Hi Max!
>
> What dose of chlorpromazine does your pdoc suggest for a hypertensive crisis? 50mg? 100mg?
>
> Ed.Oh and you should probably take something for the headache you will get. Over the counter is fine. But don't worry about having one. Just keep the med with you and enjoy life.
Maxime
Posted by SLS on January 5, 2005, at 7:56:37
In reply to Re: In the event of a hypertensive crisis..... » ed_uk, posted by jerrympls on January 3, 2005, at 21:17:52
> > To everyone who has ever taken an MAOI....
> >
> > Did you pdoc provide any medication to take in the event of a hypertensive crisis?
> >
> > What did you get? Nifedipine? Chlorpromazine?
> >
> > Ed.
>
> HI ed-
>
> I think I got Nifedipine with the instructions being to break the capsule in my mouth then swallow, lie down and call 911. This was when I was on Nardil last December.
>
> Jerry
>Actually, you might want to remain standing to reduce intracranial pressure.
- Scott
Posted by SLS on January 5, 2005, at 7:59:10
In reply to Re: Oral Phentolamine: Mexico and Brazil, posted by ed_uk on January 3, 2005, at 22:06:49
> Oral phentolamine is no longer available in the US or the UK but it is used in some countries as a treatment for erectile dysfunction.
Yes. Oral phentolamine would be the ideal emergency measure for treating a hypertensive crisis.
The US trials for ED did not show sufficient efficacy to pursue it.
- Scott
Posted by don_bristol on January 5, 2005, at 10:59:41
In reply to In the event of a hypertensive crisis....., posted by ed_uk on January 3, 2005, at 21:11:48
> To everyone who has ever taken an MAOI....
>
> Did you pdoc provide any medication to take in the
> event of a hypertensive crisis?
>
> What did you get? Nifedipine? Chlorpromazine?
>
> Ed.
----------------------------------------------------------------------
Ed, here is a couple of posts I made not long ago on this topic. I found that the old orthodoxy recommended nifedipine but that it has now been rather superceded by more appropriate meds.Take a look at these two links:
http://www.dr-bob.org/babble/20040527/msgs/351834.html
where I refer to "Dangers of Immediate-Release Nifedipine for Hypertensive Crises" and "Alternatives to Nifedipine in Hypertensive Urgencies.Also there is http://www.dr-bob.org/babble/20040527/msgs/352527.html
where (after talking about dosages) I add a few comments about emergency pills for MAOIs.Of course, I am not a doctor and if anyone has useful alternative points of view about this topic then I would welcome them here.
Best wishes
Don
Posted by ed_uk on January 5, 2005, at 16:46:20
In reply to Re: In the event of a hypertensive crisis..... » ed_uk, posted by don_bristol on January 5, 2005, at 10:59:41
Hi Don,
Thank you very much for your post :-)
Captopril sounds like an interesting option but I think that it's important to consider the mechanism by which the MAOI hypertensive crisis is believed to occur.
The problem with most articles about hypertensive emergencies is that they are not specific to MAOIs and tend to lump all forms of hypertensive crisis together.
Proposed mechanism of MAOI-tyramine hypertensive crisis.....
'Tyramine is an indirectly-acting sympathomimetic amine, one of its actions being to release norepinephrine (noradrenaline) from the adrenergic neurones associated with blood vessels which causes a rise in blood pressure by stimulating their constriction.
Normally any ingested tyramine is rapidly metabolised by the enzyme monoamine oxidase in the gut wall and liver before it escapes into general circulation. However, if the activity of the enzyme at these sites is inhibited (by the presence of an MAOI), any tyramine passes freely into circulation causing not just a rise in blood pressure, but a highly exaggerated rise due to the release from the adrenergic neurones of the large amounts of norepinephrine which accumulate there during inhibition of the MAO.'
..................................................................................................................................................................................................................................................Norepinephrine causes vasoconstriction and hence hypertension via stimulation of alpha-1 receptors. Because of this, alpha blockers such as phentolamine would seem to be the most logical treatment. Chlorpromazine, an antipsychotic, also blocks alpha-1 receptors which is why it has been used to treat MAOI hypertensive crises.
What concerns me about captopril is that although it is often an effective antihypertensive for most types of hypertension, it doesn't work on the actual cause of MAOI hypertensive crises. I don't know whether captopril would be effective treatment for MAOI-tyramine hypertension or not. One advantage of captopril is that it has been succesfully and safely used to treat other types of hypertensive crisis.
MAOI-tyramine hypertensive crises often resemble norepinephrine-secreting pheochromacytoma hypertensive crises.
From Martindale...
'Phaeochromocytoma is a rare catecholamine-secreting tumour of the adrenal medulla. Patients with phaeochromocytoma are usually hypertensive and suffer headache, palpitations, and excessive sweating; the hypertension may be either episodic or sustained. However, if the tumour is predominantly adrenaline-secreting, tachyarrhythmias may be associated with a normal or even decreased arterial pressure and if the tumour secretes mainly noradrenaline, vasoconstriction may lead to contraction of the venous pool and hypovolaemia. If the effects of the release of catecholamines are not controlled a life-threatening crisis ultimately ensues and may range from a shock-like syndrome with multiple organ failure to hypertensive crisis, depending on the predominance of the catecholamine secreted.'
IV Phentolamine is the traditional drug of choice for the management of a pheochromacytoma hypertensive crisis in hospital. In less urgent situations oral alpha blockers may be used. Oral phenoxybenzamine (Dibenzyline/Dibenyline) is an example; prazosin (Hypovase/Minipress) is also used. Beta blockers can be safely used to control tachycardia only after alpha blockers have been administered.
As far as I know, oral prazosin (an alpha-1 antagonist) has never been tested in MAOI hypertensive crises. It would seem to be a logical treatment. It is much more readily available than oral phentolamine and lacks many of the side effects of chlorpromazine. As is the case with phentolamine and chlorpromazine, excessive doses can cause hypotension. I doubt that this would occur if a low initial dose was used. I think that oral prazosin could be a useful emergency treatment for an MAOI hypertensive crisis. A suitable dose could be 0.5-1 mg. The peak plasma concentration of prazosin occurs after 1-3 hours..... this could be too slow- it is quicker than chlorpromazine though!
I still think that oral nifedipine might be suitable for some people who take MAOIs. Perhaps the safety of nifedipine could be increased by swallowing the capsule whole rather than biting into it. There is no logic behind administering nifedipine sublingually because it is not well absorbed until it is swallowed. Some of the fatalities due to nifedipine have occured in people who shouldn't really have been given nifedipine in the first place.
It's imporant to bear in mind the contra-indications of nifedipine.....
Cautions: withdraw if ischaemic pain occurs or existing pain worsens shortly after initiating treatment; poor cardiac reserve; heart failure or significantly impaired left ventricular function (heart failure deterioration observed); severe hypotension; reduce dose in hepatic impairment; diabetes mellitus; may inhibit labour; pregnancy; breast-feeding; avoid grapefruit juice (may affect metabolism).
Contra-indications: cardiogenic shock; advanced aortic stenosis; within 1 month of myocardial infarction; unstable or acute attacks of angina; porphyria.
In the UK, immediate release nifedipine is still approved for the treatment of Raynaud's phenomenon. For safety reasons, the initial dose has been reduced from 10mg down to 5mg. If people do still use nifedipine for an MAOI hypertensive crisis I think that it would be best to take an initial dose of 5mg rather than the traditional 10mg. Also, I think it might be safer to swallow the capsule whole... biting into capsules may cause a more rapid fall in blood pressure, this could be dangerous.Ed.
This is the end of the thread.
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