Dipyridamole

Indications and Usage Dipyridamole Injection is indicated as an alternative to exercise in thallium myocardial perfusion imaging for the evaluation of coronary artery disease in patients who cannot exercise adequately. In a study of about 1100 patients who underwent coronary arteriography and Dipyridamole Injection assisted thallium imaging, the results of both tests were interpreted blindly and the sensitivity and specificity of the dipyridamole thallium study in predicting the angiographic outcome were calculated. The sensitivity of the dipyridamole test (true positive dipyridamole divided by the total number of patients with positive angiography) was about 85%. The specificity (true negative divided by the number of patients with negative angiograms) was about 50%. In a subset of patients who had exercise thallium imaging as well as dipyridamole thallium imaging, sensitivity and specificity of the two tests were almost identical.

DOSAGE AND ADMINISTRATION The dose of intravenous Dipyridamole Injection as an adjunct to thallium myocardial perfusion imaging should be adjusted according to the weight of the patient. The recommended dose is 0.142 mg/kg/min (0.57 mg/kg total) infused over 4 minutes. Although the maximum tolerated dose has not been determined, clinical experience suggests that a total dose beyond 60 mg is not needed for any patient. Prior to intravenous administration, Dipyridamole Injection should be diluted in at least a 1:2 ratio with sodium chloride injection 0.45%, sodium chloride injection 0.9% or dextrose injection 5% for a total volume of approximately 20 to 50 mL. Infusion of undiluted dipyridamole may cause local irritation. Thallium-201 should be injected within 5 minutes following the 4-minute infusion of dipyridamole. Do not mix Dipyridamole Injection with other drugs in the same syringe or infusion container. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Shaking the vial should redissolve any crystals that may have formed during storage.

CONTRAINDICATIONS Hypersensitivity to dipyridamole or any of the other components of the drug.

ADVERSE REACTIONS Adverse reaction information concerning intravenous Dipyridamole Injection is derived from a study of 3911 patients in which intravenous dipyridamole was used as an adjunct to thallium myocardial perfusion imaging and from spontaneous reports of adverse reactions and the published literature. Serious adverse events (cardiac death, fatal and non-fatal myocardial infarction, ventricular fibrillation, asystole, sinus node arrest, symptomatic ventricular tachycardia, stroke, transient cerebral ischemia, seizures, anaphylactoid reaction, angioedema, and bronchospasm) are described above (see WARNINGS ). In a study of 3911 patients, the most frequent adverse reactions were: chest pain/angina pectoris (19.7%), electrocardiographic changes (most commonly ST-T changes) (15.9%), headache (12.2%) and dizziness (11.8%). Adverse reactions occurring in greater than 1% of the patients in the study are shown in the following table: Table 1 Drug-Related Adverse Reactions (%) Occurring in Greater than 1% of Patients Incidence (%) of Drug-Related Adverse Events Chest pain/angina pectoris 19.7 Headache 12.2 Dizziness 11.8 Electrocardiographic Abnormalities/ST-T changes 7.5 Electrocardiographic Abnormalities/Extrasystoles 5.2 Hypotension 4.6 Nausea 4.6 Flushing 3.4 Electrocardiographic Abnormalities/Tachycardia 3.2 Dyspnea 2.6 Pain Unspecified 2.6 Blood Pressure Lability 1.6 Hypertension 1.5 Paresthesia 1.3 Fatigue 1.2 Less common adverse reactions occurring in 1% or less of the patients within the study included: Cardiovascular System Electrocardiographic abnormalities (0.8%), arrhythmia (0.6%), palpitation (0.3%), ventricular tachycardia (0.2%-see WARNINGS ), bradycardia (0.2%), myocardial infarction (0.1%–see WARNINGS ), AV block (0.1%), syncope (0.1%), orthostatic hypotension (0.1%), atrial fibrillation (0.1%), supraventricular tachycardia (0.1%), ventricular arrhythmia (0.03%–see WARNINGS ), heart block (0.03%), cardiomyopathy (0.03%), edema (0.03%). Central and Peripheral Nervous System Hypothesia (0.5%), hypertonia (0.3%), nervousness/anxiety (0.2%), tremor (0.1%), abnormal coordination (0.03%), somnolence (0.03%), dysphonia (0.03%), migraine (0.03%), vertigo (0.03%). Gastrointestinal System Dyspepsia (1%), dry mouth (0.8%), abdominal pain (0.7%), flatulence (0.6%), vomiting (0.4%), eructation (0.1%), dysphagia (0.03%), tenesmus (0.03%), appetite increase (0.03%). Respiratory System Pharyngitis (0.3%), bronchospasm (0.2%–see WARNINGS ), hyperventilation (0.1%), rhinitis (0.1%), coughing (0.03%), pleural pain (0.03%). Other Myalgia (0.9%), back pain (0.6%), injection site reaction unspecified (0.4%), diaphoresis (0.4%), asthenia (0.3%), malaise (0.3%), arthralgia (0.3%), injection site pain (0.1%), rigor (0.1%), earache (0.1%), tinnitus (0.1%), vision abnormalities unspecified (0.1%), dysgeusia (0.1%), thirst (0.03%), depersonalization (0.03%), eye pain (0.03%), renal pain (0.03%), perineal pain (0.03%), breast pain (0.03%), intermittent claudication (0.03%), leg cramping (0.03%). In additional postmarketing experience, there have been rare reports of allergic reaction including urticaria, pruritus, dermatitis and rash.

Drug Interactions Oral maintenance theophylline and other xanthine derivatives such as caffeine may abolish the coronary vasodilatation induced by intravenous Dipyridamole Injection administration. This could lead to a false negative thallium imaging result (see CLINICAL PHARMACOLOGY – Mechanism of Action ). Myasthenia gravis patients receiving therapy with cholinesterase inhibitors may experience worsening of their disease in the presence of dipyridamole.

DESCRIPTION Dipyridamole is a coronary vasodilator described as 2,2',2'',2'''-[(4,8 Dipiperidinopyrimido[ 5,4-d]pyrimidine-2,6-diyl)dinitrilo]-tetraethanol. The structural formula is: C 24 H 40 N 8 O 4 MW 504 . 63 Dipyridamole Injection, USP is a sterile, odorless, pale yellow liquid which can be diluted in sodium chloride injection or dextrose injection for intravenous administration. Each mL contains 5 mg dipyridamole, USP, 50 mg polyethylene glycol 600 and 2 mg tartaric acid in Water for Injection, USP. pH 2.2-3.2; hydrochloric acid added for pH adjustment. Structural formula

OVERDOSAGE No cases of overdosage in humans have been reported. It is unlikely that overdosage will occur because of the nature of use (i.e., single intravenous administration in controlled settings). Signs and symptoms as described under ADVERSE REACTIONS are expected to occur and could be even more severe in single cases. Symptomatic therapy is recommended. Should severe chest pain or bronchospasm occur, parenteral aminophylline may be administered by slow intravenous injection (50-100 mg over 30 to 60 seconds) in doses ranging from 50 to 250 mg. See WARNINGS

How Supplied Dipyridamole Injection, USP is available in: 10 mL (50 mg/10 mL) SINGLE DOSE vial packaged in 5s (NDC 0641-2569-44) Storage PROTECT FROM LIGHT: Keep covered in carton until time of use. Store between 15° to 25°C (59° to 77°F). Avoid freezing. To report SUSPECTED ADVERSE REACTIONS, contact Hikma Pharmaceuticals USA Inc. at 1-877-845-0689, or the FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. For Product Inquiry call 1-877-845-0689. Manufactured by: Hikma Pharmaceuticals USA Inc. Berkeley Heights, NJ 07922 Revised December 2019 462-341-03 Product repackaged by: Henry Schein, Inc., Bastian, VA 24314 From Original Manufacturer/Distributor's NDC and Unit of Sale To Henry Schein Repackaged Product NDC and Unit of Sale Total Strength/Total Volume (Concentration) per unit NDC 0641-2569-44 10 mL SINGLE DOSE vials packaged in 5s NDC 0404-9852-10 1 10 mL SINGLE DOSE vial in a bag (Vial bears NDC 0641-2569-41) 50 mg/10 mL