Dipyridamole Information
Dipyridamole () Description
Dipyridamole () is a platelet inhibitor chemically described as 2,2',2'',2'''-[(4,8-Dipiperidinopyrimido[5,4-]pyrimidine-2,6-diyl)dinitrilo]-tetraethanol. It has the following structural formula:
CHNOMol. Wt. 504.63
Dipyridamole () , USP is intensely yellow crystalline powder or needles. It is very soluble in methanol, in alcohol, and in chloroform; slightly soluble in water; very slightly soluble in acetone and in ethyl acetate.
Each Dipyridamole () tablet intended for oral administration contains 25 mg or 50 mg or 75 mg of Dipyridamole () . In addition, each tablet contains the following inactive ingredients: corn starch, hypromellose, iron oxide yellow, lactose monohydrate, magnesium stearate, polyethylene glycol, povidone and titanium dioxide.
Dipyridamole () Clinical Pharmacology
It is believed that platelet reactivity and interaction with prosthetic cardiac valve surfaces, resulting in abnormally shortened platelet survival time, is a significant factor in thromboembolic complications occurring in connection with prosthetic heart valve replacement.
Dipyridamole () tablets have been found to lengthen abnormally shortened platelet survival time in a dose-dependent manner.
In three randomized controlled clinical trials involving 854 patients who had undergone surgical placement of a prosthetic heart valve, Dipyridamole () tablets, in combination with warfarin, decreased the incidence of postoperative thromboembolic events by 62 to 91% compared to warfarin treatment alone. The incidence of thromboembolic events in patients receiving the combination of Dipyridamole () tablets and warfarin ranged from 1.2 to 1.8%. In three additional studies involving 392 patients taking Dipyridamole () tablets and coumarin-like anticoagulants, the incidence of thromboembolic events ranged from 2.3 to 6.9%.
In these trials, the coumarin anticoagulant was begun between 24 hours and 4 days postoperatively, and the Dipyridamole () tablets were begun between 24 hours and 10 days postoperatively. The length of follow-up in these trials varied from 1 to 2 years.
Dipyridamole () tablets do not influence prothrombin time or activity measurements when administered with warfarin.
Dipyridamole () Indications And Usage
Dipyridamole () tablets are indicated as an adjunct to coumarin anticoagulants in the prevention of postoperative thromboembolic complications of cardiac valve replacement.
Dipyridamole () Contraindications
Hypersensitivity to Dipyridamole () and any of the other components.
Dipyridamole () Precautions
Dipyridamole () has a vasodilatory effect and should be used with caution in patients with severe coronary artery disease (e.g., unstable angina or recently sustained myocardial infarction). Chest pain may be aggravated in patients with underlying coronary artery disease who are receiving Dipyridamole () .
Hepatic Insufficiency:
Elevations of hepatic enzymes and hepatic failure have been reported in association with Dipyridamole () administration.
Hypotension:
Dipyridamole () should be used with caution in patients with hypotension since it can produce peripheral vasodilation.
Laboratory Tests:
Dipyridamole () has been associated with elevated hepatic enzymes.
Drug Interactions:
No pharmacokinetic drug-drug interaction studies were conducted with Dipyridamole () tablets. The following information was obtained from the literature.
Adenosine:
Dipyridamole () has been reported to increase the plasma levels and cardiovascular effects of adenosine. Adjustment of adenosine dosage may be necessary.
Cholinesterase Inhibitors:
Dipyridamole () may counteract the anticholinesterase effect of cholinesterase inhibitors, thereby potentially aggravating myasthenia gravis.
Carcinogenesis, Mutagenesis, Impairment of Fertility:
In studies in which Dipyridamole () was administered in the feed to mice (up to 111 weeks in males and females) and rats (up to 128 weeks in males and up to 142 weeks in females), there was no evidence of drug-related carcinogenesis. The highest dose administered in these studies (75 mg/kg/day) was, on a mg/m basis, about equivalent to the maximum recommended daily human oral dose (MRHD) in mice and about twice the MRHD in rats. Mutagenicity tests of Dipyridamole () with bacterial and mammalian cell systems were negative. There was no evidence of impaired fertility when Dipyridamole () was administered to male and female rats at oral doses up to 500 mg/kg/day (about 12 times the MRHD on a mg/m basis). A significant reduction in number of corpora lutea with consequent reduction in implantations and live fetuses was, however, observed at 1250 mg/kg (more than 30 times the MRHD on a mg/m basis).
Reproduction studies have been performed in mice, rabbits and rats at oral Dipyridamole () doses of up to 125 mg/kg, 40 mg/kg and 1000 mg/kg, respectively (about 1, 2 and 25 times the maximum recommended daily human oral dose, respectively, on a mg/m basis) and have revealed no evidence of harm to the fetus due to Dipyridamole () . There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, Dipyridamole () tablets should be used during pregnancy only if clearly needed.
Nursing Mothers:
As Dipyridamole () is excreted in human milkcaution should be exercised when Dipyridamole () tablets are administered to a nursing woman.
Pediatric Use:
Safety and effectiveness in the pediatric population below the age of 12 years have not been established.
Dipyridamole () Adverse Reactions
Adverse reactions at therapeutic doses are usually minimal and transient. On long-term use of Dipyridamole () tablets initial side effects usually disappear. The following reactions in Table 1 were reported in two heart valve replacement trials comparing Dipyridamole () tablets and warfarin therapy to either warfarin alone or warfarin and placebo:
Other reactions from uncontrolled studies include diarrhea, vomiting, flushing and pruritus. In addition, angina pectoris has been reported rarely and there have been rare reports of liver dysfunction. On those uncommon occasions when adverse reactions have been persistent or intolerable, they have ceased on withdrawal of the medication.
When Dipyridamole () tablets were administered concomitantly with warfarin, bleeding was no greater in frequency or severity than that observed when warfarin was administered alone. In rare cases, increased bleeding during or after surgery has been observed.
In post-marketing reporting experience, there have been rare reports of hypersensitivity reactions (such as rash, urticaria, severe bronchospasm, and angioedema), larynx edema, fatigue, malaise, myalgia, arthritis, nausea, dyspepsia, paresthesia, hepatitis, thrombocytopenia, alopecia, cholelithiasis, hypotension, palpitation, and tachycardia.
Dipyridamole () Overdosage
In case of real or suspected overdose, seek medical attention or contact a Poison Control Center immediately. Careful medical management is essential. Based upon the known hemodynamic effects of Dipyridamole () , symptoms such as warm feeling, flushes, sweating, restlessness, feeling of weakness and dizziness may occur. A drop in blood pressure and tachycardia might also be observed.
Symptomatic treatment is recommended, possibly including a vasopressor drug. Gastric lavage should be considered. Administration of xanthine derivatives (e.g., aminophylline) may reverse the hemodynamic effects of Dipyridamole () overdose. Since Dipyridamole () is highly protein bound, dialysis is not likely to be of benefit.
Dipyridamole () Dosage And Administration
The recommended dose is 75 to 100 mg four times daily as an adjunct to the usual warfarin therapy. Please note that aspirin is not to be administered concomitantly with coumarin anticoagulants.
Dipyridamole () How Supplied
Dipyridamole () Tablets USP, 25 mg are light yellow, round, biconvex, film-coated tablets debossed with ‘ZE 43’ on one side and plain on the other side are supplied as follows:
NDC 65841-662-01 in bottle of 100 tablets
NDC 65841-662-05 in bottle of 500 tablets
NDC 65841-662-10 in bottle of 1000 tablets
NDC 65841-662-30 in blister of 100 tablets
Dipyridamole () Tablets USP, 50 mg are light yellow, round, biconvex, beveled-edge, film-coated tablets debossed with ‘ZE 49’ on one side and plain on the other side are supplied as follows:
NDC 65841-663-01 in bottle of 100 tablets
NDC 65841-663-05 in bottle of 500 tablets
NDC 65841-663-10 in bottle of 1000 tablets
NDC 65841-663-30 in blister of 100 tablets
Dipyridamole () Tablets USP, 75 mg are light yellow, round, biconvex, beveled-edge, film-coated tablets debossed with ‘ZE 50’ on one side and plain on the other side are supplied as follows:
NDC 65841-664-01 in bottle of 100 tablets
NDC 65841-664-05 in bottle of 500 tablets
NDC 65841-664-10 in bottle of 1000 tablets
NDC 65841-664-30 in blister of 100 tablets
Dipyridamole () Package Label.principal Display Panel
NDC 65841-662-01 in bottle of 100 tablets
Dipyridamole () Tablets USP, 25 mg
Ronly
100 tablets
ZYDUS
NDC 65841-663-01 in bottle of 100 tablets
Dipyridamole () Tablets USP, 50 mg
Ronly
100 tablets
ZYDUS
NDC 65841-664-01 in bottle of 100 tablets
Dipyridamole () Tablets USP, 75 mg
Ronly
100 tablets
ZYDUS
