DIPYRIDAMOLE Tablets USP

Dipyridamole Tablets USP are 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: d

structural formula

Dipyridamole is an odorless yellow crystalline powder, having a bitter taste. It is soluble in dilute acids, methanol and chloroform, and practically insoluble in water.

Dipyridamole Tablets USP for oral administration contain:

dipyridamole USP 25 mg, 50 mg and 75 mg, respectively. Active Ingredient TABLETS 25 mg, 50 mg, and 75 mg:

acacia, carnauba wax, corn starch, edible white ink, lactose monohydrate, magnesium stearate, D&C yellow #10 aluminum lake, D&C red #30, helendon aluminum pink lake, sodium benzoate, methylparaben, propylparaben, polyethylene glycol, povidone, sucrose, talc, titanium dioxide, and white wax. Inactive Ingredients TABLETS 25 mg, 50 mg, and 75 mg:

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 USP 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 Tablets USP are indicated as an adjunct to coumarin anticoagulants in the prevention of postoperative thromboembolic complications of cardiac valve replacement.

Hypersensitivity to dipyridamole and any of the other components.

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 war- farin 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 USP 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 reac- tions (such as rash, urticaria, severe bronchospasm, and angioedema), larynx edema, fatigue, malaise, myalgia, arthritis, nausea, dyspepsia, paresthesia, hepatitis, thrombocytopenia, alo- pecia, cholelithiasis, hypotension, palpitation, and tachycardia.

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.

The recommended dose is 75-100 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. Adjunctive Use in Prophylaxis of Thromboembolism after Cardiac Valve Replacement.

NDC:68151-2996-0 in a PACKAGE of 1 TABLETS