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Can Antipsychotic Medication Cause Long QT Syndrome?

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Posted on Tue, 28 Feb 2017
Question: I have a concern about taking old type antipsychotics which I don't want to but have no choice.

My apologies for this long list of questions, however it would be greatly appreciated if you could answer them all.

1. Is it possible for a drug alone to cause sudden death through lqts (assuming the person has no other factors that could affect the heart)?

2. Do you have any statistics on the number of deaths through people taking drugs that cause lqts and sudden cardiac death. I would really like to see the statistics on this and to be able to find how common the problem is. (It is extremely difficult to find any such figures on the internet).

3. If you had an ecg before you started taking drugs that affected your lqts, and then had an ecg again when you were on steady doses of the drugs you were taking and it came back normal,would you then say that you had a 0% risk of developing sudden cardiac death assuming you stuck to the same dose of the medication and didn’t cause any other factor to damage your heart.

4. After stopping taking a drug that cause lqts. How long after stopping it would your heart return to normal, or does it?

5. If you only take a drug that cause lqts occasionally can that lead to sudden cardiac death?
doctor
Answered by Dr. Benard Shehu (2 hours later)
Brief Answer:
Following advice

Detailed Answer:
Hi and thank you for asking!
I read your query and understood your concerns.

First of all a single drug (especially antipsychotics) may cause acquired long qt syndrome. Long qt syndrome may lead in 20-30℅ of cases to life threatening arrhythmias (Torsade de point and ventricular fibrillation) that if unassisted may lead to sudden death.

Secondly it's important to mention predisposing factors for life threatening arrhythmias and sudden deaths, such as:
- Female sex
- Electrolyte imbalance
- Concomitant use of diuretics or antibiotics
- Familiar history for sudden death
This factors increase the risk for drug induced long qt syndrome arrhythmias and death.

Thirdly if you have a normal ECG before and during the therapy than you shouldn't worry about sudden death. You haven't drug induced long qt syndrome and haven't any increased risk for cardiac death.

Finally after stopping the drug its effect on qt segment will be gone after a couple of days (1-3 days depending on the psychotic drug. If the drug is taken on occasions without any change on ecg or without any risk factor you have no risk for cardiac death.

Hope this will be of help!
Dr. Shehu
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
doctor
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Follow up: Dr. Benard Shehu (1 hour later)
Thank you very much for your reply, it is much appreciated.

You wrote: “First of all a single drug (especially antipsychotics) may cause acquired long qt syndrome. Long qt syndrome may lead in 20-30℅ of cases to life threatening arrhythmias (Torsade de point and ventricular fibrillation) that if unassisted may lead to sudden death.”

However what I would like to know is how common it is for people to develop lqts from taking drugs that cause lqts in the first place (if possible, excluding those people who develop it as a result of other means). And how common is it for those people to then go on and experience torsade de point and ventricular fibrillation?

Given I do not possess any of the other factors that predispose individuals to life threatening arrhythmias and sudden cardiac eath, and my only risk factor is taking drugs that cause lqts, does this make my risk of developing sudden cardiac death zero? Also has anyone ever died from sudden death and faced the same medical situation as me, that being that they're only risk factor was taking a drug that could cause lqts?

My most important question is do you have any statistics on the number of deaths caused by torsade de point and ventricular fibrillation caused by people taking drugs that cause lqts. I would really like to see some statistics on this and to be able to find out how common the problem is. Is the rate of sudden cardiac death through taking a drug that affects the lqts something like one in one million or what? This is the sort of simple statistics I am looking for. There must be some statistics on this matter!!

You also wrote: “Thirdly if you have a normal ECG before and during the therapy than you shouldn't worry about sudden death. You haven't drug induced long qt syndrome and haven't any increased risk for cardiac death.” Yes I understand that but in between regular ecgs, is it not possible to develop the problem, especially if you are increasing the doses of the drugs in between having ecgs.

Also when you wrote: “If the drug is taken on occasions without any change on ecg or without any risk factor you have no risk for cardiac death.” What I was asking more was is it necessary to have an ecg at all if you only use the drug occasionally? Is there are any risk attached of lqts to only using it occasionally?

Also are there any warning signs with lqts or torsade de point and ventricular fibrillation or can the first symptom be sudden cardiac death? Are there any statistics on how common warning signs are before a fatal incident occurs.

Many thanks





doctor
Answered by Dr. Benard Shehu (13 hours later)
Brief Answer:
Following advice

Detailed Answer:
Hi back,
The risk of developing long QT syndrome in patients without predisposing factors is very minimal (less then 5℅).

The percentage of peoples with long QT syndrome that develop Torsade de point and ventricular fibrillation (without precipitating factors) is 30℅ (arround of 1.5℅of peoples taking antipsichotics).

However is advisable to monitor the patients ecg in the beginning of therapy and once a month. If there's no prolongation of qt on the ecg than the risk for sudden death and arrhythmia is almost zero.

Although you use the drug once awhile I strongly recommend that you should monitor your ecg once a month. This will help to prevent any unwanted side effects and will reasure you that everything is ok.

There's no warning signs the only signs are present at ecg this is why you should do it once a month.

Hope this will be of help
Dr. Shehu

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
doctor
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Follow up: Dr. Benard Shehu (10 hours later)
Thank you for your reply.

I am slightly confused about your statistics. You said that "The percentage of peoples with long QT syndrome that develop Torsade de point and ventricular fibrillation (without precipitating factors) is 30℅ (arround of 1.5℅of peoples taking antipsichotics)." 1.5% of people who take antipsychotics seems like a very high number to me. Are you sure it is correct?
doctor
Answered by Dr. Benard Shehu (1 hour later)
Brief Answer:
Following advice

Detailed Answer:
Hi back,

Yes my statistics are correct arround 1.5% of patients who take antipsychotics may develop arrhythmias.

Since this percentage is relatively high (because it may lead to life threatening situations); it's recommended that patients who take antipsychotics should do the ecg before, and once a month (or once in two months).

If the ECG is normal you shouldn't worry about sudden death and arrhythmias.

Hope this will be of help!
Wish you health!
Dr. Shehu
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
doctor
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Follow up: Dr. Benard Shehu (1 hour later)
Many thank for your reply.

Out of all the patients on antipsychotics, assuming they all were given regular ecgs, am I correct to assume that none of them would experience fatal arrhythmias and sudden death because their ecgs would notify you that the patient is in danger in continuing their medication?

Also, although ecgs are very important, isn't it possible to develop lqts and torsade de pointes in-between ecgs (especially if you are increasing the doses of medications you are taking)?
doctor
Answered by Dr. Benard Shehu (8 hours later)
Brief Answer:
Following advice

Detailed Answer:
Hi back,

Yes as long as the basal ECG (before therapy) is normal and you haven't any predisposing factors for long QT syndrome you haven't any increased risk.

Only in patients with higher risk (those with predisposing factors, mentioned above) is recommended that the ecg should be done within one week after starting (or increasing the dose) therapy.

Hope this will be of help!
Wish you health!
Dr. Shehu
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
doctor
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Follow up: Dr. Benard Shehu (31 hours later)
Thank you for your answers.

Can you also please tell me if there have ever been any documented incidents of an individual with a normal healthy heart experiencing long qt syndrome and/or sudden cardiac death through taking the drug lisdexamfetamine or any other stimulant type drug such as adderall?

Also how accurate are ECGs at identifying long qt syndrome? Please try to provide a percentage out of 100 if you can.
doctor
Answered by Dr. Benard Shehu (19 hours later)
Brief Answer:
Following advice

Detailed Answer:
Hi back,

Lisdexamfetamine is one of the safiest antipsychotic drugs and there's no reported sudden cardiac death from it (in patients with basal normal ecg.

Ecg is the only way to detect and to evaluate long QT syndrome. QT is an ECG parametees and its prolongation is detected on ecg. This is why ecg has 100% of accuracy.

Wish you health!
Dr. Shehu
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
doctor
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Follow up: Dr. Benard Shehu (31 hours later)
Thank you for your answer but I am slightly confused by it.

All over the internet there are warnings about drugs that cause long qt syndrome and I have read in a number of places that lisdexamfetamine is one of them. I have also read that many antidepressants can cause the syndrome, is this not correct?

Another medication that I was taking on a regular basis was domperidone, but this has now become a prescription only medication because of the effect it has on the qt interval of the heart. Are you saying that this drug also does not cause long qt syndrome?
doctor
Answered by Dr. Benard Shehu (11 hours later)
Brief Answer:
Following advice...

Detailed Answer:
Hi back,

Apart from what you have read on line, the studies has shown that lisdexamfetamine has no significant effects (compared with placebo) on corrected QT intervals.

On the other hands Domperidone is a drug that prolong the QT interval and as a such it shouldn't be administered in patients who are taking antidepressants.

Hope this will be of help!
Wish you health!
Dr. Shehu
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
doctor
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Dr. Benard Shehu

Cardiologist

Practicing since :2004

Answered : 2257 Questions

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Can Antipsychotic Medication Cause Long QT Syndrome?

Brief Answer: Following advice Detailed Answer: Hi and thank you for asking! I read your query and understood your concerns. First of all a single drug (especially antipsychotics) may cause acquired long qt syndrome. Long qt syndrome may lead in 20-30℅ of cases to life threatening arrhythmias (Torsade de point and ventricular fibrillation) that if unassisted may lead to sudden death. Secondly it's important to mention predisposing factors for life threatening arrhythmias and sudden deaths, such as: - Female sex - Electrolyte imbalance - Concomitant use of diuretics or antibiotics - Familiar history for sudden death This factors increase the risk for drug induced long qt syndrome arrhythmias and death. Thirdly if you have a normal ECG before and during the therapy than you shouldn't worry about sudden death. You haven't drug induced long qt syndrome and haven't any increased risk for cardiac death. Finally after stopping the drug its effect on qt segment will be gone after a couple of days (1-3 days depending on the psychotic drug. If the drug is taken on occasions without any change on ecg or without any risk factor you have no risk for cardiac death. Hope this will be of help! Dr. Shehu