Antipsychotic medication and venous thrombosis

Associations between venous thromboembolism and antipsychotics. A study of the WHO database of adverse drug reactions

BACKGROUND

Concern has been raised about the occurrence of venous thromboembolism (VTE) during treatment with antipsychotics. However, to date, clozapine is the only antipsychotic agent for which recurring evidence supports an association with VTE. Therefore, the aim of this study was to investigate the association between antipsychotic drugs, including clozapine and VTE.

STUDY DESIGN AND METHODS

Data mining of the WHO database of adverse drug reactions (ADRs) using Bayesian statistics is in routine use for early alerting to possible ADRs. An information component measure was used to investigate the association between antipsychotic drugs and VTE reactions in the database.

RESULTS

A total of 754 suspected cases of VTE related to treatment with antipsychotics had been reported. After excluding cases related to clozapine, 379 cases remained. A robust association was found for the second-generation antipsychotics group but not for the high-potency, first-generation antipsychotics group or the low-potency first-generation antipsychotics group. The individual compounds with statistically significant associations were olanzapine, sertindole and zuclopenthixol. A time-dependent analysis showed that the associations were positive for these drugs in 2002, 2001 and 2003, respectively. Case analyses were undertaken after excluding ten suspected duplicate reports. Of the remaining 369 cases, 91 cases were associated with olanzapine, 9 with zuclopenthixol and 6 with sertindole.

CONCLUSIONS

VTE was more often reported with the antipsychotic drugs olanzapine, sertindole and zuclopenthixol than with other drugs in the WHO database. Further studies are warranted to explain this disproportional reporting. Since the associations found were based on incomplete clinical data, the results should be considered as preliminary and interpreted cautiously.

Antipsychotics associated with pulmonary embolism in a Swedish medicolegal autopsy series

To determine the association between fatal pulmonary embolism and use of antipsychotic drugs in a Swedish medicolegal autopsy series. Persons aged 18-65 years and subjected to a medicolegal autopsy in 1992-2005 were selected. On the basis of external cause of death, determined by the forensic pathologist, unnatural deaths (including fatal intoxications) were excluded and participants in whom pulmonary embolism was the cause of death were identified. Use of antipsychotics was based on the results of the postmortem analyses and categorized as use of high-potency first-generation antipsychotics, low-potency first-generation antipsychotics, second-generation antipsychotics or no use of antipsychotics. Logistic regression analyses were performed. Use of antipsychotics was verified in 538 of the 14,439 included participants. Pulmonary embolism was recorded as the cause of death in 279 participants and 33 of these used antipsychotics. Use of low-potency first-generation antipsychotics and second-generation antipsychotics was significantly associated with fatal pulmonary embolism (adjusted odds ratio: 2.39; 95% confidence interval: 1.46-3.92 and 6.91; 95% confidence interval: 3.95-12.10, respectively). Out of 26 participants classified as high-potency first-generation antipsychotic drug users, none had pulmonary embolism as the cause of death. Pulmonary embolism was overrepresented among medicolegal autopsy cases identified as users of low-potency first-generation and second-generation antipsychotics.

Antidepressant drug use and risk of venous thromboembolism

STUDY OBJECTIVE

To evaluate the risk of idiopathic venous thromboembolism associated with antidepressant use and to further assess the risk by class of antidepressant and by individual antidepressant drug.

DESIGN

Nested case-control study.

DATA SOURCE

United Kingdom General Practice Research Database.

SUBJECTS

Seven hundred eighty-two case patients with a confirmed diagnosis of venous thromboembolism who were taking an antidepressant drug and 3085 matched control subjects.

MEASUREMENTS AND MAIN RESULTS

We identified all people in the database aged 70 years or younger with venous thromboembolism who had filled at least one prescription for an antidepressant drug between 1990 and 2005; up to four control subjects were matched to each case patient by age, sex, practice attended, index date, and duration of computerized medical record. We compared the risks of current and recent use of antidepressant drugs with nonuse of an antidepressant before the index date (date of diagnosis of venous thromboembolism) by using conditional logistic regression. Current exposure to tricyclic antidepressants was associated with a small increased risk of idiopathic venous thromboembolism compared with nonuse (odds ratio [OR] 1.4, 95% confidence interval [CI] 1.1-1.8), whereas we found no increased risk among users of selective serotonin reuptake inhibitors or other antidepressant drugs. When we evaluated individual drugs, we found that amitriptyline conferred an increased risk of thromboembolism (OR 1.7, 95% CI 1.2-2.4) that increased with increasing dose (> 25 mg/day). No other individual antidepressant drug was associated with an increase in risk of venous thromboembolism.

CONCLUSION

Current exposure to amitriptyline, particularly at high doses, was associated with an increased risk of idiopathic venous thromboembolism.

Deaths from natural causes in people with mental illness: a cohort study

OBJECTIVES

To investigate natural-cause mortality risk in people with psychiatric admission histories in a national population-based cohort. To estimate risks in relation to psychiatric diagnostic categories and for specific causes of death.

METHODS

We studied a 21-year cohort (1973-93) of 4.1 million Danish adults with linkage to national psychiatric and mortality registers. Person years were stratified by psychiatric diagnostic category and age-standardized mortality ratios (SMRs) were estimated versus the general population.

RESULTS

Risks of death by natural causes were higher across a range of psychiatric illnesses in both sexes. We observed SMRs greater than 200 in men and women with alcoholism, drug abuse, organic psychoses, dementia, and learning difficulties. Alcoholism and drug misuse in particular were important causes of premature mortality. The highest cause-specific SMRs were for nervous system diseases, gastrointestinal diseases, lung diseases, and "all other natural causes"; the lowest were for neoplasm. The greatest excess, in terms of absolute numbers, was for circulatory disease mortality.

CONCLUSION

Adults experiencing a range of psychiatric illnesses are more likely to die at any age, and also prematurely, from natural causes. The consistency of elevated risk across psychiatric diagnoses and causes of death indicates an important health inequality. Those involved in planning and providing mental health services should address the heightened need for physical health care in psychiatric patients.

Assessment of risk of venous thromboembolism and its possible prevention in psychiatric patients

AIMS

The aim of the present study was to compile a specific algorithm of prevention of venous thromboembolism in hospitalized psychiatric patients because this specific issue has not been addressed sufficiently in the literature.

METHODS

The computer database MEDLINE was searched using key words (schizophrenia OR depression OR bipolar) AND (antipsychotic OR antidepressant) AND (venous thromboembolism OR pulmonary embolism) AND (prevention OR prophylaxis) in 2006.

RESULTS

Based on the literature regarding non-surgical and surgical patients with respect to specificities in mental disorders (obesity induced with psychotropic drugs, possible catatonia, physical restraint, potential dehydration, antipsychotic treatment), a scoring system and a synoptic algorithm of prevention of venous thromboembolism modified for hospitalized psychiatric patients, were suggested.

CONCLUSIONS

According to the authors' knowledge this is the first attempt to establish such guidelines exclusively in psychiatry. Individual preventative clinical measures are suggested, ranging from regular physical exercise of lower extremities to repeated parenteral application of high doses of heparin tailored to every patient's risk for venous thromboembolism. Economic data support implementation of a proposed decision procedure into psychiatric clinical practice. Prospective discussion of its international applicability would be beneficial from both the clinical and the scientific points of view.

In vitro effects of antipsychotics on human platelet adhesion and aggregation and plasma coagulation

1. Several studies suggest an association between venous thromboembolism and the use of antipsychotic drugs, especially clozapine, but the biological mechanisms are unknown. It has been suggested that antipsychotic drugs enhance aggregation of platelets and thereby increase the risk of venous thrombosis. The purpose of the present study was to examine the effects of clozapine and its main metabolite, N-desmethyl clozapine, as well as olanzapine, risperidone and haloperidol, on platelet adhesion and aggregation and on plasma coagulation in vitro. 2. Blood was collected from healthy subjects free of medication. Platelet adhesion to different protein surfaces and aggregation were measured in microplates. The coagulation methods of activated partial thromboplastin time (APTT) and prothrombin time were performed in platelet-poor plasma. 3. Clozapine was the only compound that increased platelet adhesion and aggregation and shortened APTT. The effect appeared at therapeutic concentrations and was significant but weak. 4. This weak effect of clozapine on haemostasis may explain, in part, the association of this compound and venous thromboembolism.

Schizophrenia, neuroleptic medication and mortality

BACKGROUND

There is an excess of death from natural causes among people with schizophrenia.

AIMS

Schizophrenia and its treatment with neuroleptics were studied for their prediction of mortality in a representative population sample of 7217 Finns aged >/= 30 years.

METHOD

A comprehensive health examination was carried out at baseline. Schizophrenia was determined using the Present State Examination and previous medical records.

RESULTS

During a 17-year follow-up, 39 of the 99 people with schizophrenia died. Adjusted for age and gender, the relative mortality risk between those with schizophrenia and others was 2.84 (95% CI 2.06-3.90), and was 2.25 (95% CI1.61-3.15) after further adjusting for somatic diseases, bloodpressure, cholesterol, body mass index, smoking, exercise, alcohol intake and education. The number of neuroleptics used at the time of the baseline survey showed a graded relation to mortality. Adjusted for age, gender, somatic diseases and other potential risk factors for premature death, the relative risk was 2.50 (95% CI1.46-4.30) per increment of one neuroleptic.

CONCLUSIONS

There is an urgent need to ascertain whether the high mortality in schizophrenia is attributable to the disorder itself or the antipsychotic medication.

Deep venous thrombosis and pulmonary embolism following physical restraint

OBJECTIVE

We describe a case of deep venous thrombosis (DVT) and pulmonary embolism (PE) following the use of physical restraint in a patient with a diagnosis of acute delusional psychotic disorder.

METHOD

A new case report of DVT and PE associated with prolonged physical restraint is presented. The literature on physical restraint, DVT, and PE was reviewed using a search of Medline and Psychinfo from 1966 to the present.

RESULTS

Four other reported cases of DVT and PE were found in association with physically restrained patients.

CONCLUSION

Risk of DVT and PE in association with immobilization during physical restraint may occur in spite of no pre-existing risk factors. Medical guidelines for the prevention of thrombosis following physical restraint are presented. Despite the absence of controlled trials of treatment effectiveness, the catastrophic outcome of DVT and PE warrants early and vigorous intervention in patients undergoing physical restraint.

Massive pulmonary thromboembolism demonstrated at necropsy in Japanese psychiatric patients treated with neuroleptics including atypical antipsychotics

BACKGROUND

There may be an increased risk of pulmonary thromboembolism (PTE) with antipsychotic drugs, so this association was investigated in autopsy cases of sudden unexpected death determined by the Department of Legal Medicine of a Japanese university hospital.

METHODS AND RESULTS

Records of 1,125 forensic autopsies (808 males, 317 females) performed during the study period for investigation of the cause of sudden unexpected death were reviewed and a logistic regression analysis was performed to explore whether age, gender, body mass index (BMI), and antipsychotic drug use were associated with fatal PTE. Among all records, 34 (3.0%; 14 males, 20 females) indicated the use of antipsychotic drugs and 28 (2.5%; 9 males, 19 females) indicated PTE as the cause of death. Of the 28 subjects who died from PTE, 8 had taken antipsychotic drugs (29%) and all were female. Female gender and antipsychotic drug use accounted for a significantly higher risk of PTE death with an odds ratio of 4.22 (95% confidence interval (CI), 1.82-9.78; p<0.01) and 10.49 (95% CI, 3.95-27.85; p<0.01), respectively.

CONCLUSIONS

Japanese women taking antipsychotic drugs may be at particular risk for PTE.

Left atrial thrombosis associated with antipsychotic drugs

The authors report a case of a 36-year-old shizophrenic patient with left atrial thrombosis. There have been small number of case reports of antipsychotic drugs-associated thromboembolic events. All of them are venous ones. This paper describes the first case of atrial thrombosis associated with antipsychotic drugs.

In vitro effects of risperidone and 9-hydroxy-risperidone on human platelet function, plasma coagulation, and fibrinolysis

BACKGROUND

Thrombotic events have been reported with the use of antipsychotic compounds, although the incidence, predisposing factors, and biological mechanisms associated with these events in psychiatric patients are subject to debate.

OBJECTIVE

The in vitro actions of risperidone and its active metabolite 9-hydroxy-risperidone (9-OH-risperidone) on human platelet function, plasma coagulation, and fibrinolysis were examined to explore whether hematologic effects might be a mechanism for thrombotic events with these compounds.

METHODS

Blood was donated by healthy white male subjects who were free of medications (particularly acetylsalicylic acid and nonsteroidal anti-inflammatory compounds). Platelet shape change and adhesion/aggregation reactions to risperidone and 9-OH-risperidone induced by adenosine diphosphate (ADP), collagen, epinephrine, and 5-hydroxytryptamine (5-HT) were tested in human platelet-rich plasma. Arachidonic acid metabolism was assessed in human platelets and rat aortic rings. Plasma coagulation was tested in human platelet-poor plasma. Fibrinolysis was measured in human whole blood.

RESULTS

The 12 study subjects ranged in age from 20 to 40 years (median age 30 years). At concentrations of 1 x 10(-5) mol/L (approximately 4180 ng/mL), neither risperidone nor 9-OH-risperidone induced platelet shape change or aggregation, amplified reactions to ADP, or modified platelet adhesion/aggregation induced by collagen or ADP, but they did attenuate epinephrine-induced platelet aggregation (-50% in the case of 9-OH-risperidone; P < 0.05) and 5-HT-induced platelet aggregation (drug concentrations yielding 50% inhibition of 5-HT-induced platelet aggregation, 0.5 and 0.2 ng/mL, respectively). Cyclooxygenase, thromboxane A2 synthase, 12-lipoxygenase, prostacyclin synthase, plasma coagulation, and fibrinolysis were unaffected.

CONCLUSIONS

Risperidone and 9-OH-risperidone reduced epinephrine- and 5-HT-induced human platelet aggregation but did not significantly alter other measures of platelet function, plasma coagulation, or fibrinolysis in vitro.

Fatal Venous Thromboembolism Associated with Antipsychotic Therapy

OBJECTIVE:

To describe the occurrence of pulmonary embolism (PE) as a rare adverse effect of clozapine that is treatable, but sometimes fatal, and survey the literature on the subject in the hope of increasing awareness of the potential danger that may result from drug interactions.

CASE SUMMARY:

A 47-year-old woman treated with clozapine and paroxetine was admitted to the hospital with dyspnea and swelling of the leg. The patient was diagnosed as having PE and was treated with intravenous heparin. On hospital day 7, sudden acute respiratory failure developed and the patient died. Postmortem examination confirmed the existence of massive PE.

DISCUSSION:

The woman had no identifiable risk factors other than receiving a combination of clozapine and paroxetine, with a demonstrated elevated clozapine blood concentration. Use of the Naranjo probability scale revealed a probable likelihood that the adverse reaction was drug related.

CONCLUSIONS:

The association of antipsychotic drugs and venous thromboembolism has been previously described, but is still a rare finding. This case highlights the importance of monitoring and possibly discontinuing treatment when venous thrombosis is suspected. There should be careful monitoring, especially in patients with risk factors for thrombosis. Finally, antidepressant—antipsychotic drug combinations can increase the risk of rare adverse effects, such as venous thromboembolism, even in the absence of other risk factors.

Massive pulmonary embolism in a young patient on clozapine therapy

Clozapine-associated induction of venous thromboembolism has potentially catastrophic consequences. We report a case of sudden death caused by bilateral main pulmonary trunk thrombosis in a 31-year-old man receiving clozapine therapy. The patient presented with general weakness and exertional dyspnea. Bilateral main pulmonary trunk thrombosis was clearly demonstrated by helical chest computed tomography.

Psychotropic drugs and fatal pulmonary embolism

PURPOSE

To examine the association between the use of psychotropic drugs and fatal pulmonary embolism.

METHODS

We conducted a national case-control study of fatal pulmonary embolism. Cases were 75 New Zealand men and women aged 15-59 years who died between 1 January 1990 and 31 December 1998, where the underlying cause of death was certified as codes 415.1, 451 or 453 of the International Classification of Diseases (9th Revision). Four controls, matched for sex and age, were selected from the general practice to which each case had belonged. Information was abstracted from the records of general practitioners, family planning clinics and psychiatric services. Odds ratios and 95% confidence intervals (95% CI) were estimated using conditional logistic regression. The key analyses were restricted to cases (n = 62) and controls (n = 243) without major risk factors for venous thromboembolism.

RESULTS

Compared to non-use, the adjusted odds ratio for current use of antipsychotic drugs was 13.3 (95% CI: 2.3-76.3). Low potency antipsychotics appeared to carry the highest risk (odds ratio: 20.8 [95% CI: 1.7-259.0]). The main drug involved was thioridazine. The odds ratio for current use of antidepressants was also increased, at 4.9 (95% CI: 1.1-22.5).

CONCLUSIONS

Our results for conventional antipsychotics are consistent with previous studies of non-fatal venous thromboembolism. The finding for antidepressants needs to be replicated in other studies.

Psychopharmacohazardology: major hazards of the new generation of psychotherapeutic drugs

Balancing the benefits and risks of prescribing psychotherapeutic drugs requires knowledge of the baseline risks of genetics, lifestyle and morbidity of untreated illness. Superimposed upon these risks are some rare but potentially dangerous, uncomfortable or irreversible hazards of the antipsychotics, mood stabilizers, antidepressants and tranquillizers. Knowledge of these hazards facilitates monitoring and prompt intervention at the earliest sign of problems.

Antipsychotic-induced venous thromboembolism: a review of the evidence

Psychiatric disorders themselves and treatment with conventional antipsychotic medications have in a number of early studies been associated with venous thromboembolism. In general, information on the relationship between antipsychotics and this possible adverse effect is in the form of case reports and open cross-sectional studies. However, recently the association between conventional antipsychotics and venous thrombosis has been strengthened as a result of the publication of a large, nested, case-control study. In this study, low-potency antipsychotic drugs were more strongly associated with venous thrombosis than high-potency drugs. In addition, recent epidemiological data support an association between the atypical antipsychotic agent clozapine and venous thromboembolism. The risk for venous thromboembolism seems to be highest during the initial months of treatment with antipsychotics. The biological mechanisms responsible for this possible adverse drug reaction are unknown, but a number of hypotheses have been suggested. The increased risk may be the result of drug-induced sedation, obesity, hyperleptinaemia, antiphospholipid antibodies and increased activity in the coagulation system. The association could also be related to underlying risk factors present in patients with psychosis such as smoking. Despite the limitations of present knowledge, clinicians should be aware of this possible adverse drug reaction and should consider interrupting or changing the antipsychotic regimen in patients in whom this reaction is suspected. More studies are needed in order to further elucidate this adverse effect, particularly to determine the incidence rate, possible predisposing factors and the biological mechanisms involved.

Acute massive pulmonary thromboembolism associated with risperidone and conventional phenothiazines

To assess the contribution of antipsychotic medication in Japanese patients suffering acute massive pulmonary thromboembolism, records of patients with idiopathic pulmonary thromboembolism associated with antipsychotic medication who were seen in a Japanese Emergency Center from January 1996 to December 2000 were reviewed. Age, gender, physical status, clinical presentation, antiphospholipid antibody, outcome, psychiatric profile, and antipsychotic medication use were examined. Seven patients had acute pulmonary thromboembolism associated with antipsychotic drug use, representing 44% of all patients with idiopathic pulmonary thromboembolism. The 7 patients developed symptoms in the early morning. More women than men were affected. In 5 cases, chlorpromazine and other phenothiazines had been prescribed, whereas in 2 cases, risperidone, a mixed serotonin 5HT(2A) and dopamine D(2) receptor antagonist, had been taken for 40 days and 6 days, respectively. In 4 cases, including the patients taking risperidone, antiphospholipid antibodies were not present. Although statistically significant conclusions can not be drawn from this study, the data suggest that patients receiving risperidone, as well as conventional phenothiazines, are at risk for acute pulmonary thromboembolism, even if otherwise healthy. Strong affinity for the 5HT(2A) receptor of the novel antipsychotic may increase coagulability and the risk of thromboembolism.