1.
Dipyridamole and paracetamol overdose resulting in multi-organ failure.
Cullis, PS, Watson, D, Cameron, A, McKee, RF
Scottish medical journal. 2013;(3):e14-7
Abstract
Dipyridamole intoxication is rare and few reports exist amongst the current literature. A case of dipyridamole and paracetamol overdose is described in a previously healthy 58-year-old woman, which resulted in multi-organ failure requiring dialysis, inotropic support, ventilation and extensive surgical intervention for small bowel ischaemia. This case highlights the dangers of an unusually large overdose of a commonly prescribed drug, and reviews current knowledge of dipyridamole intoxication.
2.
Combination antiplatelet therapy for secondary stroke prevention: enhanced efficacy or double trouble?
Usman, MH, Notaro, LA, Nagarakanti, R, Brahin, E, Dessain, S, Gracely, E, Ezekowitz, MD
The American journal of cardiology. 2009;(8):1107-12
Abstract
The evaluation of antithrombotic agents for secondary stroke prevention has focused on stroke reduction. The aim of this analysis was to focus specifically on the increase in bleeding risk. The annualized rates of total and major bleeding events in secondary stroke prevention trials of antithrombotics were assessed and cross compared. A Medline search for major randomized clinical studies with a follow-up duration of > or =1 year identified 13 studies. Pooled data sets were used to compare mean bleeding rates for aspirin (< or =325 mg/day), clopidogrel, anticoagulants (warfarin and other vitamin K antagonists), aspirin plus clopidogrel, and aspirin plus extended-release dipyridamole (ER-DP). Total bleeding occurred at mean rates of 4.8% with aspirin (< or =325 mg/day) alone, 2.9% with clopidogrel alone, 3.6% with aspirin plus ER-DP, 10.1% with aspirin plus clopidogrel, and 16.8% with anticoagulation. Major bleeding occurred at mean rates of 1% with aspirin (< or =325 mg/day) alone, 0.85% with clopidogrel, 0.93% with aspirin plus ER-DP, 1.7% with aspirin plus clopidogrel, and 2.5% with anticoagulation. In conclusion, the combination of aspirin and clopidogrel is associated with significantly greater bleeding than either aspirin (< or =325 mg/day) or clopidogrel alone. Aspirin plus ER-DP has a greater bleeding rate than clopidogrel but a lower rate than aspirin (< or =325 mg/day) alone.
3.
Dipyridamole for preventing stroke and other vascular events in patients with vascular disease.
De Schryver, EL, Algra, A, van Gijn, J
The Cochrane database of systematic reviews. 2003;(1):CD001820
Abstract
BACKGROUND Patients with transient ischaemic attacks (TIA) and minor ischaemic strokes are at risk of serious vascular events (death from all vascular causes, non-fatal stroke, or non-fatal myocardial infarction). Their risk of vascular events lies between 4 and 11 percent per year. Aspirin only, in a daily dose of 30 mg or more, offers only modest protection in such patients: it reduces the incidence of major vascular events by 13 percent. In a single trial, adding dipyridamole (an alternative antiplatelet agent) to aspirin was associated with a 22 percent reduction in the risk of major vascular events compared with aspirin alone. However, a systematic review of all trials of antiplatelet agents by the Antithrombotic Trialists' Collaboration showed that, in high risk patients, there was virtually no difference between the aspirin-dipyridamole combination and aspirin alone. We therefore sought to assess the effects of dipyridamole in more detail. OBJECTIVES 1) To assess the efficacy of dipyridamole versus control in the secondary prevention of vascular events in patients with vascular disease in the presence and absence of other antiplatelet drugs. 2) To assess the safety of dipyridamole versus control in the secondary prevention of vascular events in patients with vascular disease in the presence and absence of other antiplatelet drugs. SEARCH STRATEGY The Cochrane Stroke Group Trials Register was searched and other relevant Cochrane Groups were contacted to search their specialised registers (last search 29 April 2002). In addition the Cochrane Controlled Trials Register, MEDLINE and EMBASE were searched and Dutch manufacturers of dipyridamole were contacted to identify further published and unpublished studies. SELECTION CRITERIA Randomised long term secondary prevention trials with concealed treatment allocation, treatment for > 1 month, starting within 6 months after presentation of a arterial vascular disease were selected (coronary artery disease, myocardial infarction, angina pectoris, retinopathy, nephropathy, peripheral arterial disease, stroke, TIA, amaurosis fugax). Therapy consisted of dipyridamole in any dose in the presence or absence of other antiplatelet drugs compared with no drug or an antiplatelet drug(s) other than dipyridamole (control group). DATA COLLECTION AND ANALYSIS Two reviewers selected trials which met the inclusion criteria and extracted details of randomisation methods, blinding of treatments and assessments, whether intention-to-treat analysis was possible from the published data, whether treatment groups were comparable with regard to major prognostic factors, the number of patients who were excluded or lost to follow-up, definition of outcome events, and entry and exclusion criteria. The methodological quality of each trial was assessed by the two reviewers on the basis of these extracted data. In addition, dose and type of antiplatelet treatments, duration of follow-up and the numbers of defined outcome events were recorded. Data published by the Antithrombotic Trialists' Collaboration were used. The remaining data were independently extracted by the same two reviewers and cross checked. Data were analysed according to the intention-to-treat principle. Relative and absolute risk reductions were calculated by means of the statistical software provided by the Cochrane Collaboration (RevMan). MAIN RESULTS Twenty-six trials were included, with a total of 19842 patients, among whom 1399 vascular deaths and 3085 fatal and non-fatal vascular events occurred during follow-up. Compared with control, dipyridamole had no clear effect on vascular death (RR 1.02, 95% CI 0.90 to 1.17). This result was not influenced by the dose of dipyridamole or type of presenting vascular disease. Compared with control, dipyridamole appeared to reduce the risk of vascular events (RR 0.90, 95% CI 0.83 to 0.98), but this effect was only statistically significant due to a single large trial in patients presenting with cerebral ischaemia (6602 patients). Comparing dipyridamole plus aspirin with aspirin alone: there was no clear difference in vascular death, the RR was 1.03 (95% CI 0.87 to 1.22); the combination was associated with fewer vascular events with an RR of 0.90 (95% CI 0.80 to 1.00). Combination treatment of dipyridamole and aspirin compared with placebo had an RR of 0.89 (95% CI 0.79 to 1.01) for vascular death and an RR of 0.74 (95% CI 0.68 to 0.80) for vascular events. REVIEWER'S CONCLUSIONS This review found that, for patients who presented with arterial vascular disease, there was no evidence that dipyridamole, in the presence or absence of an other antiplatelet drug (chiefly aspirin) reduced the risk of vascular death, though it may reduce the risk of further vascular events. However, this benefit was found in only a single large trial and only in patients presenting after cerebral ischaemia. There was no evidence that dipyridamole alone was more efficacious than aspirin. Further trials comparing the effects of the combination of dipyridamole with aspirin with aspirin alone are justified.