Effects of Antithrombotic and Results of Drug Screening
Josef Hladovec in Antithrombotic Drugs in Thrombosis Models, 2020
Dipyridamole, a pyrimido-pyrimidine derivative, was originally used since 1961 as a vasodilating agent with main indications in coronary diseases. It is this origin as a vasodilating agent that dipyridamole has in common with some other drugs exerting antithrombotic effects, such as pentoxifylline, suloctidil, ketanserin, calcium channel blockers, beta-adrenolytics, etc. Nevertheless, the favorable clinical effect of dipyridamole based on vasodilatation, e.g., in angina pectoris, has never been positively proven and the rationality of such indications remains questionable. Of course, other mechanismsm might contribute to some favorable effects. Already in the phase of testing as a vasodilating agent, it was supposed that the main mechanism of action might be accumulation of adenosine in the plasma due to the inhibition of its cellular uptake and metabolism (deamination) e.g., in erythrocytes and endothelial cells. In this way, the well known vasodilating effect of adenosine could be potentiated. First experimental studies suggesting the use of dipyridamole as an antithrombotic appeared in 196595 and the following years saw an explosion of interest in this use of the drug even before that of aspirin. Experimental and clinical studies amounted to several thousands, but in spite of that, and just as in the case of aspirin, it is still uncertain how the drug acts or whether its clinical use is fully justified.
Alternative Approaches to Treatment of Women with Anti-Phospholipid Antibodies and Fetal Loss
E. Nigel Harris, Thomas Exner, Graham R. V. Hughes, Ronald A. Asherson in Phospholipid-Binding Antibodies, 2020
An antiplatelet agent, usually aspirin, has been an integral part of treatments for women with anti-phospholipid antibodies. Aspirin given in doses under 150 mg/day preferentially block arterial thromboxane synthesis.5 Such pediatric dosages are associated with few (if any) maternal or fetal risks. The doses given did not affect neonatal platelet aggregation studies.6 Concerns about in utero closure of the fetal ductus, but no significant fetal or neonatal consequences have been described in patients treated with much larger doses.7 The use of dipyridamole in pregnancy is largely European, because a U.S. consensus report suggested that this drug is not an effective antithrombotic agent when used alone or with aspirin in other groups of patients.8 Little has been reported with respect to potential fetal or maternal risks associated with dipyridamole.
How to master MCQs
Chung Nen Chua, Li Wern Voon, Siddhartha Goel in Ophthalmology Fact Fixer, 2017
Carotid artery stenosis can give rise to recurrent TIAs and stroke. The stenosis caused by an atheroma is found usually at the bifurcation of the common carotid artery. The bruit is best heard over the angle of the jaw. The annual risk of stroke is 8% for cerebral TIAs and 2% for ocular TIAs. However, the cause of death is usually myocardial infarction rather than stroke. Endarterectomy is superior to medical treatment in symptomatic cases with significant stenosis of over 70%. Endarterectomy has not been shown to be advantageous over medical treatment in moderate stenosis of between 50 and 60%. Aspirin is the medication of choice. Dipyridamole can be given as an alternative but has no additive effect.
Effect of dipyridamole on random pattern skin flap viability in rats
Published in Journal of Plastic Surgery and Hand Surgery, 2020
Dipyridamole is an antiaggregant agent devised to be used in coronary artery disease due to its vasodilating effect. It also blocks platelet adhesion and aggregation. It shows its effect through inhibition of phosphodiesterase enzyme located in platelets, blocking adenosine intake in erythrocytes and increasing prostaglandin I2 (PG I2) production in endothelium [9,26–35]. Clinically it is used in ischemic stroke, transient ischemic attack, acute coronary syndrome and prevention of thrombosis in patients with a prosthetic valve [34–36]. Cilostazol is an antiaggregant agent -similarly to dipyridamole- acting through phosphodiesterase inhibition. Considering proved beneficial effects of cilostazol and other anti aggregant agents such as acetylsalicylic acid, hirudin and clopidogrel on flap survival, we have concluded that dipyridamole might have beneficial effect in preventing distal flap necrosis in random pattern skin flaps [11,14,16–18,21,23,30,31].
Advances in small-molecule therapy for managing angina pectoris in the elderly
Published in Expert Opinion on Pharmacotherapy, 2019
Nida Waheed, Ahmad Mahmoud, Cecil A. Rambarat, Carl J. Pepine
Dipyridamole is another phosphodiesterase inhibitor that blocks adenosine metabolism by platelets and endothelial cells resulting in coronary vasodilation and inhibition of platelet aggregation. In the 1980s, a meta-analysis of 11 randomized controlled trials suggested improvement in angina, especially with higher doses of dipyridamole with longer durations of therapy [68]. However, by the 1990s, there were more studies indicating its lack of efficacy in treating angina. One study focused on prescribing patterns of dipyridamole among the elderly population (mean age in men 82.6 years, women 80.8 years) after the FDA had removed angina pectoris as an indication for its use and found that many elderly patients were prescribed dipyridamole despite limited evidence on its efficacy [69]. The PISA trial was subsequently performed and randomized 400 patients to assess the efficacy and safety of dipyridamole in patients with chronic stable angina [70]. It found that the antianginal and anti-ischemic effects of dipyridamole were comparable to placebo when assessed by total exercise duration, time to angina pain, and time to ST-segment depression. The PISA-PET study was subsequently performed in chronic stable angina patients with an average age of 61 years to assess if there was an effect on myocardial perfusion and coronary microvascular function with dipyridamole [71]. The main finding was decreased resting blood flow in ischemic areas of the myocardium without significant improvement in hyperemic flow.
Diagnosis of coronary artery disease: potential complications of imaging techniques
Published in Acta Cardiologica, 2022
Evangelos Sdogkos, Andrew Xanthopoulos, Grigorios Giamouzis, John Skoularigis, Filippos Triposkiadis, Ioannis Vogiatzis
Arrhythmias during diagnostic tests are usually due to the agents administered to detect stress-induced ischaemia. This can happen in both single-photon emission computed tomography (SPECT) and stress echocardiography. The occurrence of dangerous ventricular arrhythmias, although very unlikely, requires immediate treatment. Special care should also be taken when administering dipyridamole, or adenosine, to patients with atrioventricular conduction disorders since both may cause transient block at the atrioventricular node, and therefore the subsequent hemodynamic collapse of the patient. Nevertheless, dipyridamole is considered safer than dobutamine for major side effects (1/1000 vs. 1/300 exams) or deaths (1/10,000 vs. 1/5000), respectively. Finally, attention is required in patients with asthma or bronchospasm because the above stressors may exacerbate these diseases [8]. Regarding contrast echocardiography, ultrasound-enhancing agents’ use is extremely safe since they have not been proven to increase the rate of mortality or myocardial infarction. Minor adverse events include back pain, nausea, and headache and have a very low incidence. The incidence of severe allergic reactions and anaphylactoid reactions is considered negligible (0.01% and 0.006%, respectively). They are contraindicated only in case of a known or suspected hypersensitivity to their contents. [9]
Related Knowledge Centers
- Blood Pressure
- Ccl2
- Coronary Artery Disease
- Pulmonary Hypertension
- Thrombus
- Vasodilation
- Nucleoside Transporter
- Pde3 Inhibitor
- Medication
- Peripheral Artery Disease