Dipyridamole adverse effects

The incidence of major adverse reactions to dipyridamole was determined in a multicenter retrospective study, involving 73 806 patients who underwent intravenous dipjridamole stress imaging in 59 hospitals and 19 countries (4). The main conclusion was that the risk of serious dipjridamole-induced adverse effects is very low, a conclusion that is in line with other reports (5), and comparable to that reported for exercise testing in a similar patient population. Combined major adverse events among the entire patient population included 7 cardiac deaths (0.95 per 10000), 13 non-fatal myocardial infarctions (1.76 per 10000), 6 non-fatal sustained ventricular dysrhythmias (0.81 per 10000) (ventricular tachycardia in 2 and ventricular fibrillation in 4), 9 transient cerebral ischemic attacks (1.22 per 10000), 1 stroke, and 9 severe cases of bronch-ospasm (1.22 per 10000). Minor non-cardiac adverse effects were less frequent among the elderly and more frequent in women and patients taking maintenance aspirin. 

Dipyridamole- ° thallium imaging has been used to assess cases of suspected coronary disease (SEDA-15, 506) (SEDA-16, 537) (SEDA-17, 539). It is difficult to distinguish the adverse effects of dipyridamole from those of the pharmaceutical agent (dipyridamole- thal-lium), since dipyridamole can cause bronchospasm. In one series of 400 examinations, there was severe chest pain due to myocardial ischemia in 9% of cases, milder chest pain (probably not associated with cardiac events) in 21%, and severe hypotension in 2.5% (10). Others have reported instances of cardiovascular collapse (SEDA-15, 506). 

Adverse effects with dipyridamole thallium testing are minimal, the main adverse effects being chest pain (with or without ischemic changes on the ECG), headache, dizziness, and nausea. Adverse effects are related to the increased adenosine activity and can be ameliorated by xanthine compounds because they are direct competitive antagonists of adenosine. Caffeine products must be avoided for about 24 hours prior to the test. Adenosine is associated with a higher incidence of adverse effects (80% versus 50%), but these are very transient, and some studies have shown that patients prefer it over dipyridamole. Both agents are relatively contraindicated in patients with a history of bronchospasm. 

A 79-year-old woman taking a combination of low-dose aspirin and extended-release dipyridamole (Aggrenax) became profoundly bradycardic (36 bpm), dizzy and almost fainted 2 minutes after the start of an adenosine infusion for radionuclide myocardial imaging. Adenosine was stopped, and she recovered within 2 minutes. The last dose oiAggrenox had been taken 12 hours previously. However, note that bradycardia is a known adverse effect of adenosine. ... 

These reports need to be set in a broad context. A very extensive study of high-dose dipyridamole echocardiography (10451 tests in 9 122 patients) noted significant adverse effects in only 96 patients, with major adverse reactions occurring in just 7 patients. Three of the 7 developed asystole and two of these patients were taking unnamed beta blockers. ... 

Regadenoson has an improved side effect profile in comparison to adenosine and dipyridamole. However, it may also precipitate myocardial infarction. This adverse effect is secondary to coronary steal phenomenon induced by regadenoson administration. Most likely, in this mechanism A2A vasodilatation causes intercoronary and transmxual steal phenomenon which in the presence of a preexisting stenotic lesion results in myocardial infarction [6]. 

Platelet inhibitors are widely used in the treatment and prevention of coronary artery disease. In addition to acetic salicylic acid (ASA), two major groups of platelet inhibitors are used phosphodiesterase inhibitors, including dipyridamole, and thienopyridines. Clopidogrel is the most widely used antiplatelet agent and in combination with ASA, it is the standard-of-care (SoC) for acute coronary s5mdromes and percutaneous coronary interventions. However, the mechanisms of action include pathways that affect the metabolic activity of bone cells and pharmacologic modulation of these pathways may have adverse effects on the bones. 

Adverse reactions at therapeutic doses are usually minimal and transient. With long-term use, initial side effects usually disappear. The following reactions were reported in 2 heart valve replacement trials comparing dipyridamole and warfarin therapy to either warfarin alone or warfarin and placebo dizziness, abdominal distress, headache, and rash. 

It appears that xanthine derivatives such as caffeine and theophylline might antagonise some of the haemodynamic effects of dipyridamole because they act as competitive antagonists of adenosine (an endogenous vasodilator involved in the action of dipyridamole). Due to these opposing effects, parenteral aminophylline has been used to treat adverse events associated with intravenous dipyridamole, - and it is recommended that aminophylline should be made available before beginning dipyridamole echocardiography. ... 

---