Risk of Blood Clots Linked to Seroquel, Other Atypical Antipsychotics: Study

The use of newer atypical antipsychotic medications, such as Seroquel, Thorazine and Risperdal, has been associated with an overall increase in the risk of blood clots, according to British researchers.  

A new study published in the British Medical Journal looks at the rate of blood clots in people who are taking various antipsychotic drugs. The findings indicate that people who use any antipsychotics are at greater risk for venous thromboembolism, or blood clots, but the highest risk was associated with people who take atypical antipsychotics.

The researchers looked at clinical records of 115,000 people in the U.K. and found a 32% increased risk of blood clots among those that had been prescribed antipsychotics in the last two years. The risk increased to 56% for people who had been using the drugs as recently as the last three months, and patients who had been newly prescribed antipsychotics in the last three months were 97% more likely to suffer blood clots than people not taking the drugs.

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The results of the study indicate that atypical antipsychotics, as a class, were more closely associated with blood clot risks than conventional antipsychotics. The findings also indicate that patients taking two or more different antipsychotics were at even more risk, with double the chance of suffering a blood clot than someone taking none of the drugs.

Side effects of Seroquel were associated with the highest risk, with users suffering blood clots at a nearly 3-to-1 ratio over people not taking any antipsychotics.

Seroquel (quetiapine fumarate) is an atypical-antipsychotic that is a top selling drug for AstraZeneca, generating nearly $5 billion a year in sales. Originally approved by the FDA in 1997 for the treatment of schizophrenia, it has been frequently prescribed off-label for uses that were not approved as safe and effective at the time, such as anxiety, obsessive dementia, compulsive disorders and autism.

AstraZeneca had faced about 22,500 Seroquel lawsuits from plaintiffs who claimed the drug caused diabetes and weight gain. However, the company has reached Seroquel settlements in the majority of those cases.

An editorial posted in connection with the study noted that the reason patients had been prescribed the atypical antipsychotics could not be determined in 99% of the cases. With one drug, prochlorperazine, scientists estimated that 80% of the prescriptions were for off-label uses, such as nausea and vomiting.

9 Comments

  • TeresaJanuary 15, 2024 at 12:01 am

    I was just diagnosed with blood clots in my lungs. I just read seroquel can cause blood clots.i don't know what to do. I need it because I have severe insomnia.i don't know what to do

  • GladysNovember 25, 2021 at 3:34 am

    My sister died in July 2021. She did not have any medical condition but Bipolar Disease. She had been taking Quetiapina for years. She was only 59 years old but died in her sleep. I blame Quetiapina for her sudden death.

  • AtillaSeptember 16, 2021 at 2:04 pm

    My mom has just been prescribed Quetiapine due to AZ. She has Mitral valve calcification. She had several blood clots in her body in the past. She is on Warfarin and Metoprolol. After reading package insert of Quetiapine on the net I was scared. I need clarification. Why does FDA not ban it?

  • ColleenAugust 27, 2021 at 10:40 pm

    I'm a 20-year-old female who was prescribed Serouquel in April of 2021, on the 1st of August 2021 I was diagnosed with having a pulmonary embolism. Doctors didn't know why I had it cause I'm an active and healthy person with no apparent genetic conditions... After reading this page, I suspect that it was the seroquel

  • WilliamDecember 15, 2020 at 5:45 pm

    I was prescribed Seroquel in November of 2018. In July of 2020 I was diagnosed with massive clotting in my femoral veins...especially the thrombus/ common vien... running from my knee past my groin and up mid abdominal. I have been on blood tests thinner and it shrank some but is now almost completely precluded in my common where it now stops in my groin area, again knee to groin! I am a Veteran a[Show More]I was prescribed Seroquel in November of 2018. In July of 2020 I was diagnosed with massive clotting in my femoral veins...especially the thrombus/ common vien... running from my knee past my groin and up mid abdominal. I have been on blood tests thinner and it shrank some but is now almost completely precluded in my common where it now stops in my groin area, again knee to groin! I am a Veteran and hopeful for surgery with the VA soon.

  • EvanJune 30, 2020 at 4:29 am

    I’ve been on seroquel for almost 7 years. In June of 2018 I was diagnosed having 3 PE blood clots in my left lung. Not sure if there’s a link, but definitely think there is. I’m lucky to survive this, and fear everyday that it’ll happen again.

  • Donna BFebruary 25, 2014 at 7:19 pm

    I have recently been diagnosed of having a blood clot in a valve in my small bowel. Gp at hospital said this was due to me being lieden factor v. Which I have apparently had all of my 44yrs of life. I am now wondering if I was born with this condition, if at all I have it or has this blood clot been caused due to the fact being prescribed and me taking qutiapine for approximatly 12 months.

  • HeatherNovember 24, 2012 at 6:40 pm

    My 35 year old sister just died. The Coroner told us it was due to three blood clots that moved through her heart and killed her instantaneously. Pamela, do EVERYTHING you can to get her off of that medicine before it's too late. My sister died on October 26th, 2012. 3 days before her 37th birthday.

  • PamelaNovember 1, 2012 at 12:04 pm

    My sister, who is 63, took Seroquel for about 5 years, and then developed diabetes and blood clots. She is in the hospital for the 3rd time now after having had an aortic aneurism. She is in critical condition. THey are calling it a blood disorder, but I feel sure the only problem she really had was insomnia. She has Asperger's. Is there any way to help her and her husband?

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