Among other properties, dipyridamole acts as a vasodilator. It should be used with caution in patients with severe coronary artery disease, including unstable angina and/or recent myocardial infarction, left ventricular outflow obstruction or haemodynamic instability (e.g. decompensated heart failure).
Dipyridamole should be used with caution in patients with coagulation disorders.
In patients with myasthenia gravis, readjustment of therapy may be necessary after changes in dipyridamole dosage (see Drug Interactions).
Patients treated with regular oral doses of dipyridamole should not receive additional intravenous dipyridamole. If pharmacological stress testing with intravenous dipyridamole for coronary artery disease is considered necessary, then oral dipyridamole should be discontinued 24 hours prior to testing.
A small number of cases have been reported in which unconjugated dipyridamole was shown to be incorporated into gallstones to a variable extent (up to 70% by dry weight of stone). These patients were all elderly, had evidence of ascending cholangitis and had been treated with oral dipyridamole for a number of years. There is no evidence that dipyridamole was the initiating factor in causing gallstones to form in these patients. It is possible that bacterial deglucuronidation of conjugated dipyridamole in the bile may be the mechanism responsible for the presence of dipyridamole in gallstones.
Excipients in the formulation:
• Liquid maltitol (E965) 2500mg in each 5 ml. Patients with a rare hereditary problem of fructose intolerance should not take this medicine.
• Propylene glycol (E1520). This medicine contains 136.3mg in each 5 ml. Co-administration with any substrate for alcohol dehydrogenase such as ethanol may induce serious adverse effects in neonates.
• Ethanol. This medicine contains 10.4 mg of alcohol (ethanol) in each 5 ml. The amount in 5 ml of this medicine is equivalent to less than 3 ml beer or 1 ml wine. The small amount of alcohol in this medicine will not have any noticeable effects.
• The medicine also contains parahydroxybenzoates which are known to cause urticaria, generally delayed type reactions such as contact dermatitis and rarely, immediate reaction with urticaria and bronchospasm.
• This medicine contains less than 1 mmol sodium (23 mg) per ml, that is to say essentially 'sodium-free'.