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What Causes Negative Reaction To Haloperidol?
Question: FOR Dr. Ilir Sharka ONLY
Hello Dr Sharka
I did not close the question, I do not know what happened!!
Anyway to continue with our question…
You said that people have an “idiosyncratic reaction to haloperidol (similar to allergic reactions)”, does this mean that once you have tried the drug and have not experienced any bad reaction that you never will?
One side effect I have read about for haloperidol and quetiapine is irregular heartbeat, which I understand though not life threatening, can be dangerous. Under what circumstances could this side effect become fatal? Also, once you stop taking the antipsychotics would your heartbeat automatically go back to normal or not?
Hello Dr Sharka
I did not close the question, I do not know what happened!!
Anyway to continue with our question…
You said that people have an “idiosyncratic reaction to haloperidol (similar to allergic reactions)”, does this mean that once you have tried the drug and have not experienced any bad reaction that you never will?
One side effect I have read about for haloperidol and quetiapine is irregular heartbeat, which I understand though not life threatening, can be dangerous. Under what circumstances could this side effect become fatal? Also, once you stop taking the antipsychotics would your heartbeat automatically go back to normal or not?
Brief Answer:
My answer as follows:
Detailed Answer:
Hello!
Welcome back again on HCM!
Regarding idiosyncratic reaction from haloperidol, it usually occurs in the first days from starting haloperidol.
But the fact that it doesn't occur in the first days, does not mean that it can not occur later. If the dose of haloperidol is raised after some time, it imposes some risk for the occurrence of this disorder.
Regarding irregular heart beat, you should know that it can be called cardiac arrhythmia in the medical dictionary. There are different types of cardiac arrhythmia (or irregular heart beat), from mild forms to life-threatening forms.
But, irregular heart beats are related to the QT interval prolongation. As I explained to you these changes in the ECG can be monitored and when this effect is noticed, the drug can be stopped.
Hope you will find this answer helpful!
Kind regards,
Dr. Iliri
My answer as follows:
Detailed Answer:
Hello!
Welcome back again on HCM!
Regarding idiosyncratic reaction from haloperidol, it usually occurs in the first days from starting haloperidol.
But the fact that it doesn't occur in the first days, does not mean that it can not occur later. If the dose of haloperidol is raised after some time, it imposes some risk for the occurrence of this disorder.
Regarding irregular heart beat, you should know that it can be called cardiac arrhythmia in the medical dictionary. There are different types of cardiac arrhythmia (or irregular heart beat), from mild forms to life-threatening forms.
But, irregular heart beats are related to the QT interval prolongation. As I explained to you these changes in the ECG can be monitored and when this effect is noticed, the drug can be stopped.
Hope you will find this answer helpful!
Kind regards,
Dr. Iliri
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
Thank you for that answer.
I was recently for approximately one month taking quetiapine at doses up to 75mg a night 3-4 nights a week to help with sleeping. Do you think I need to have an ecg?
Also even if the qt interval of your heart is affected by being on antipsychotics, doesn’t your heart simply return back to normal once you come off the drugs?
Also I have a few questions about neuroleptic malignant syndrome, if that is okay?
- Is neuroleptic malignant syndrome what you would worry about most if you were to try haloperidol?
- Can you tell me what the probability is of developing the syndrome after taking haloperidol?
- I have tried risperidone, quetiapine and olanzapine in the past and never developed the syndrome, does that make me any less likely to develop it?
- Can you tell me what the mortality rate is for it?
- Do you remain conscious throughout it?
I was recently for approximately one month taking quetiapine at doses up to 75mg a night 3-4 nights a week to help with sleeping. Do you think I need to have an ecg?
Also even if the qt interval of your heart is affected by being on antipsychotics, doesn’t your heart simply return back to normal once you come off the drugs?
Also I have a few questions about neuroleptic malignant syndrome, if that is okay?
- Is neuroleptic malignant syndrome what you would worry about most if you were to try haloperidol?
- Can you tell me what the probability is of developing the syndrome after taking haloperidol?
- I have tried risperidone, quetiapine and olanzapine in the past and never developed the syndrome, does that make me any less likely to develop it?
- Can you tell me what the mortality rate is for it?
- Do you remain conscious throughout it?
Brief Answer:
My answer as follows:
Detailed Answer:
Hello again!
Let me explain as follows:
A resting ECG is always necessary periodically when taking antipsychotics.
If the QT interval is affected, it can turn to normality when the drug is stopped (or after a short period of time).
Regarding Malignant neuroleptic syndrome, I would explain that it more frequent when taking haloperidol, compared to new generation antipsychotics like quetiapine, risperidone or olanzapine.
But, this is not the adverse effect which I worry the most. As I explained to you before, the most common adverse effects of haloperidol are dystonia, parkinson's syndrome and tardive dyskinesia. These adverse effects are very common when haloperidol is used for a long time and can have a direct impact in your quality of life. That is why I would not recommend taking haloperidol in young patients and for a long time.
While, Malignant neuroloptic syndrome occurs in less than 1% of the patients taking Haloperidol and the mortality rates from 5% in early detected and well treated patients up to 30% when there is delay in the diagnosis or treatment. It can cause confusion and in the advanced stages coma, but you do not loose conscience in an abrupt way (just gradually).
Hope to have been helpful!
Let me know about everything!
Regards,
Dr. Iliri
My answer as follows:
Detailed Answer:
Hello again!
Let me explain as follows:
A resting ECG is always necessary periodically when taking antipsychotics.
If the QT interval is affected, it can turn to normality when the drug is stopped (or after a short period of time).
Regarding Malignant neuroleptic syndrome, I would explain that it more frequent when taking haloperidol, compared to new generation antipsychotics like quetiapine, risperidone or olanzapine.
But, this is not the adverse effect which I worry the most. As I explained to you before, the most common adverse effects of haloperidol are dystonia, parkinson's syndrome and tardive dyskinesia. These adverse effects are very common when haloperidol is used for a long time and can have a direct impact in your quality of life. That is why I would not recommend taking haloperidol in young patients and for a long time.
While, Malignant neuroloptic syndrome occurs in less than 1% of the patients taking Haloperidol and the mortality rates from 5% in early detected and well treated patients up to 30% when there is delay in the diagnosis or treatment. It can cause confusion and in the advanced stages coma, but you do not loose conscience in an abrupt way (just gradually).
Hope to have been helpful!
Let me know about everything!
Regards,
Dr. Iliri
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
I understand a resting ecg is always necessary when taking antipsychotics however due to the way in which I was taking the tablets (not at a high dose and not every day), is it necessary to still have an ecg. My psychiatrist and doctor did not seem to think so because otherwise I would have been sent for one. Should I be on the cautious side and ask for one? Or given that I haven’t taken the drug in a number of weeks now is there any point (since the qt interval can turn back to normal)?
I have tried risperidone, quetiapine and olanzapine in the past and never developed malignant neuroleptic syndrome, does that make me any less likely to develop it?
Can you tell me the probability of developing the syndrome when taking the drug in the form of numbers like this: 1/100,000 patients?
I am confused by why you believe “dystonia, parkinson's syndrome and tardive dyskinesia” are worse than malignant neuroleptic syndrome because the latter is a disorder that can kill you very quickly, can you explain why you said what you said?
Is there anything I could do that would improve my chances of living if I got the syndrome? (Perhaps have somebody with me ready to go the hospital to explain to the doctors the name of the syndrome?)
I have tried risperidone, quetiapine and olanzapine in the past and never developed malignant neuroleptic syndrome, does that make me any less likely to develop it?
Can you tell me the probability of developing the syndrome when taking the drug in the form of numbers like this: 1/100,000 patients?
I am confused by why you believe “dystonia, parkinson's syndrome and tardive dyskinesia” are worse than malignant neuroleptic syndrome because the latter is a disorder that can kill you very quickly, can you explain why you said what you said?
Is there anything I could do that would improve my chances of living if I got the syndrome? (Perhaps have somebody with me ready to go the hospital to explain to the doctors the name of the syndrome?)
Brief Answer:
My opinion as follows:
Detailed Answer:
I understand your concern and would explain as follows:
- As you have used antipsychotics not every day and in low doses, there is not need to perform a resting ECG as it will probably result normal. I agree with your on the fact that your doctor would have asked it, if it were really necessary.
- As you have tried these other antipsychotics without developing malignant neuroleptic syndrome, this is a very reassuring fact that you have less chances to develop this syndrome with haloperidol. Anyway, Haloperidol belongs to a different pharmacological group compared to the other drugs and we can be very sure about such predictions.
- Yes, the frequency of this syndrome is about 1/100000 patients. It is unpredictable. You can not predict it. But if your feel muscle pain and fever, these are signs which indicate that you should go to the hospital. But there is no way to predict these symptoms.
Regarding the other adverse effects such as tardive dyskinesia, parkinson's syndrome, I agree with you on the fact that these are not life-threatening conditions. But they are progressive medical conditions, which damage your ability to move, walk and talk normally, with a slow gradual progression and worsening. As they are more frequent compared to malignant neuroleptic syndrome, I would recommend you to consider them, because they can really worsen your quality of life, and unfortunately the treatments are not very effective.
Hope to have been helpful!
Let me know about everything!
Wishing all the best,
Dr. Iliri
My opinion as follows:
Detailed Answer:
I understand your concern and would explain as follows:
- As you have used antipsychotics not every day and in low doses, there is not need to perform a resting ECG as it will probably result normal. I agree with your on the fact that your doctor would have asked it, if it were really necessary.
- As you have tried these other antipsychotics without developing malignant neuroleptic syndrome, this is a very reassuring fact that you have less chances to develop this syndrome with haloperidol. Anyway, Haloperidol belongs to a different pharmacological group compared to the other drugs and we can be very sure about such predictions.
- Yes, the frequency of this syndrome is about 1/100000 patients. It is unpredictable. You can not predict it. But if your feel muscle pain and fever, these are signs which indicate that you should go to the hospital. But there is no way to predict these symptoms.
Regarding the other adverse effects such as tardive dyskinesia, parkinson's syndrome, I agree with you on the fact that these are not life-threatening conditions. But they are progressive medical conditions, which damage your ability to move, walk and talk normally, with a slow gradual progression and worsening. As they are more frequent compared to malignant neuroleptic syndrome, I would recommend you to consider them, because they can really worsen your quality of life, and unfortunately the treatments are not very effective.
Hope to have been helpful!
Let me know about everything!
Wishing all the best,
Dr. Iliri
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
Thank you for that answer.
I am glad to hear that having tried other antipsychotics I am less likely to develop malignant neuroleptic syndrome, but are you sure you are correct about that, are you sure that makes me less likely to get it? Also do you know how much less likely that makes me to develop the syndrome in terms of my odds? (And yes I understand haloperidol is from a different pharmacological group and therefore there is still a very severe risk.)
I asked you to tell me the probability of developing malignant neuroleptic syndrome when taking haloperidol, and I asked you to use a format like 1/100,000. I asked you to provide me the answer in that format because that would be easy for me to understand and would not be confusing like when doctors talk of deaths per ‘patient years’. The figure I wrote of 1/100,000 was a random number, I was just showing you the format that I would like you to use to show your answer. So can you please provide me an accurate figure for the number of people that will develop malignant neuroleptic syndrome because of taking haloperidol?
I am glad to hear that having tried other antipsychotics I am less likely to develop malignant neuroleptic syndrome, but are you sure you are correct about that, are you sure that makes me less likely to get it? Also do you know how much less likely that makes me to develop the syndrome in terms of my odds? (And yes I understand haloperidol is from a different pharmacological group and therefore there is still a very severe risk.)
I asked you to tell me the probability of developing malignant neuroleptic syndrome when taking haloperidol, and I asked you to use a format like 1/100,000. I asked you to provide me the answer in that format because that would be easy for me to understand and would not be confusing like when doctors talk of deaths per ‘patient years’. The figure I wrote of 1/100,000 was a random number, I was just showing you the format that I would like you to use to show your answer. So can you please provide me an accurate figure for the number of people that will develop malignant neuroleptic syndrome because of taking haloperidol?
Brief Answer:
My answer as follows:
Detailed Answer:
Hello again!
I would explain that the incidence of Malignant neuroleptic syndrome is about 0.01-0.02% in patients taking haloperidol. Converted in another scale, it would be 10-20/100.000 patients.
I can not determine exactly how much less likely you are supposed to develop this syndrome, considering the fact that you have tried those other anti-psychotics.
As you see, the risk for this disorder is really low, and considering the fact that you didn't develop this syndrome when taking the other anti-psychotics, it means that your risk can be ten times lower compared to other patients, which calculated would be 1-2/100.000.
Hope to have clarified some of your uncertainties!
Kind regards,
Dr. Iliri
My answer as follows:
Detailed Answer:
Hello again!
I would explain that the incidence of Malignant neuroleptic syndrome is about 0.01-0.02% in patients taking haloperidol. Converted in another scale, it would be 10-20/100.000 patients.
I can not determine exactly how much less likely you are supposed to develop this syndrome, considering the fact that you have tried those other anti-psychotics.
As you see, the risk for this disorder is really low, and considering the fact that you didn't develop this syndrome when taking the other anti-psychotics, it means that your risk can be ten times lower compared to other patients, which calculated would be 1-2/100.000.
Hope to have clarified some of your uncertainties!
Kind regards,
Dr. Iliri
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
Thank you for that answer.
The percentage that you kindly provided, "0.01-0.02%", I was suprised by, I thought it would be worse. Because haloperidol is an older antipsychotic I thought the percentage would have been higher and from the brief research I have done online the percentage I think is 0.2-3.2% (and 0.01-0.02% is for newer antipsychotics). (Please correct me if I am wrong doctor.)
Do you know of any other medications other than haloperidol that are as effective as haloperidol for controlling agitation, excluding benzodiazepines (because I have a tolerance to them)?
The percentage that you kindly provided, "0.01-0.02%", I was suprised by, I thought it would be worse. Because haloperidol is an older antipsychotic I thought the percentage would have been higher and from the brief research I have done online the percentage I think is 0.2-3.2% (and 0.01-0.02% is for newer antipsychotics). (Please correct me if I am wrong doctor.)
Do you know of any other medications other than haloperidol that are as effective as haloperidol for controlling agitation, excluding benzodiazepines (because I have a tolerance to them)?
Brief Answer:
My answer as follows:
Detailed Answer:
Hello again!
Yes, you are right to say that this is a low percentage, but different studies show different data.
In fact the occurrence of this syndrome can vary from 0.1-2.2% of the patients.
Of course haloperidol carries a five fold higher risk for this syndrome compared to new generation anti-psychotics.
Anyway, different studies show different data, and we can not come into a
Regarding the time of onset of neuroleptic malignant syndrome, I would explain that it ranges from 1-44 days after initiation of anti-psychotic drug therapy; mean onset is 10 days.
The male-to-female ratio is 2:1, which means that it happens twice in men compared to women.
All anti-psychotics are helpful against agitation. But the time of their effect differs. Usually haloperidol and old anti-psychotics have a faster effect compared to newer anti-psychotics, but they are not preferred as long term therapy because of their adverse effects (as we have mentioned above).
Anyway, I am not a specialist of the field (psychiatry) and can not give a professional opinion on anti-psychotics.
You should discuss with your psychiatrist on the above issues and maybe try low doses of haloperidol or try to use higher doses of your previous used anti-psychotics.
Maybe an anti-epilepsy drug (carbamazepine, valproate) could also help stabilize your situation, when combined with an anti-psychotic.
Hope you will find this answer helpful!
Kind regards,
Dr. Iliri
My answer as follows:
Detailed Answer:
Hello again!
Yes, you are right to say that this is a low percentage, but different studies show different data.
In fact the occurrence of this syndrome can vary from 0.1-2.2% of the patients.
Of course haloperidol carries a five fold higher risk for this syndrome compared to new generation anti-psychotics.
Anyway, different studies show different data, and we can not come into a
Regarding the time of onset of neuroleptic malignant syndrome, I would explain that it ranges from 1-44 days after initiation of anti-psychotic drug therapy; mean onset is 10 days.
The male-to-female ratio is 2:1, which means that it happens twice in men compared to women.
All anti-psychotics are helpful against agitation. But the time of their effect differs. Usually haloperidol and old anti-psychotics have a faster effect compared to newer anti-psychotics, but they are not preferred as long term therapy because of their adverse effects (as we have mentioned above).
Anyway, I am not a specialist of the field (psychiatry) and can not give a professional opinion on anti-psychotics.
You should discuss with your psychiatrist on the above issues and maybe try low doses of haloperidol or try to use higher doses of your previous used anti-psychotics.
Maybe an anti-epilepsy drug (carbamazepine, valproate) could also help stabilize your situation, when combined with an anti-psychotic.
Hope you will find this answer helpful!
Kind regards,
Dr. Iliri
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
Thank you for that answer.
With neuroleptic malignant syndrome, can it kill healthy young people even when there is an early diagnosis or is it only people with serious pre-existing health conditions and the very young and elderly?
Would starting from a very low dose make my chances of developing neuroleptic malignant syndrome zero or would there still be some risk?
Also, earlier you said "considering the fact that you didn't develop this syndrome when taking the other anti-psychotics, it means that your risk can be ten times lower compared to other patients", are you sure about this doctor? Ten times less likely seems an awful lot, can you tell me where you found this information out?
With neuroleptic malignant syndrome, can it kill healthy young people even when there is an early diagnosis or is it only people with serious pre-existing health conditions and the very young and elderly?
Would starting from a very low dose make my chances of developing neuroleptic malignant syndrome zero or would there still be some risk?
Also, earlier you said "considering the fact that you didn't develop this syndrome when taking the other anti-psychotics, it means that your risk can be ten times lower compared to other patients", are you sure about this doctor? Ten times less likely seems an awful lot, can you tell me where you found this information out?
Brief Answer:
My answer as follows:
Detailed Answer:
Hello again!
I understand your concern and would explain that starting at low doses and increasing slowly lowers the risk for developing malignant neuroleptic syndrome, but it does not make it 0. There is still some chances (in the first days as above explained) to develop this syndrome.
It can affect young and old patients, but surely it is more frequent when other commodities are present, like heart failure or a myopathy.
Regarding your last question, I would explain that I have come into this conclusion after reading many studies on this syndrome and anti-psychotics. There are many studies on this issue (we can read them on specialized medical literature on Pubmed), but there are different data in different studies. Anyway, the risk is much lower when other anti-psychotics have been tried. The mechanism remains unknown.
Hope to have clarified some of your uncertainties!
Wishing good health,
Dr. Iliri
My answer as follows:
Detailed Answer:
Hello again!
I understand your concern and would explain that starting at low doses and increasing slowly lowers the risk for developing malignant neuroleptic syndrome, but it does not make it 0. There is still some chances (in the first days as above explained) to develop this syndrome.
It can affect young and old patients, but surely it is more frequent when other commodities are present, like heart failure or a myopathy.
Regarding your last question, I would explain that I have come into this conclusion after reading many studies on this syndrome and anti-psychotics. There are many studies on this issue (we can read them on specialized medical literature on Pubmed), but there are different data in different studies. Anyway, the risk is much lower when other anti-psychotics have been tried. The mechanism remains unknown.
Hope to have clarified some of your uncertainties!
Wishing good health,
Dr. Iliri
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
Thank you for that answer.
I was just rereading your second to last post, and noticed that some of your sentence was missing, can you complete it for me? The sentence was: “Anyway, different studies show different data, and we can not come into a”.
In your second to last post you wrote: “Regarding the time of onset of neuroleptic malignant syndrome, I would explain that it ranges from 1-44 days after initiation of anti-psychotic drug therapy; mean onset is 10 days.” If I took haloperidol for one day and then stopped, would I then theoretically be at risk for developing NMS for up to 44 days? And if not 44 days then do you know how many?
I was just rereading your second to last post, and noticed that some of your sentence was missing, can you complete it for me? The sentence was: “Anyway, different studies show different data, and we can not come into a”.
In your second to last post you wrote: “Regarding the time of onset of neuroleptic malignant syndrome, I would explain that it ranges from 1-44 days after initiation of anti-psychotic drug therapy; mean onset is 10 days.” If I took haloperidol for one day and then stopped, would I then theoretically be at risk for developing NMS for up to 44 days? And if not 44 days then do you know how many?
Brief Answer:
My answer as follows:
Detailed Answer:
Hello again!
I am sorry about the sentence, maybe a system error. I wanted to say" Anyway, different studies studies show different data, and we can not come into a specific conclusion, because the patient populations differs from study to study.".
If you took haloperidol for just one day, its effects would go away within 48 hours, so you would not be at any risk for malignant neuroleptic syndrome in the next days. Just for that 48 hours.
Hope to have been helpful!
Kind regards,
Dr. Iliri
My answer as follows:
Detailed Answer:
Hello again!
I am sorry about the sentence, maybe a system error. I wanted to say" Anyway, different studies studies show different data, and we can not come into a specific conclusion, because the patient populations differs from study to study.".
If you took haloperidol for just one day, its effects would go away within 48 hours, so you would not be at any risk for malignant neuroleptic syndrome in the next days. Just for that 48 hours.
Hope to have been helpful!
Kind regards,
Dr. Iliri
Note: For further queries related to coronary artery disease and prevention, click here.
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
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