Interaction between Lepirudin and Heparin (flush)
Major Synergy

ID DDInter1037 and DDInter857
Interaction The concomitant use of heparin and direct thrombin inhibitors may increase the risk of bleeding complications due to additive or synergistic effects on the clotting cascade. Moreover, since direct thrombin inhibitors are used for the treatment of thrombosis in patients with heparin-induced thrombocytopenia (HIT) and for anticoagulation in patients with or at risk for HIT, heparin would not be indicated in these patients.
Management Patients with known HIT should not receive any heparin. All formulations of heparin, including heparin lock flush, should be withdrawn prior to and during the treatment of heparin-induced thrombocytopenia. Clinicians should allow sufficient time for heparin's effect on the activated partial thromboplastin time (aPTT) to decrease prior to initiation of the thrombin inhibitor. Close clinical and laboratory observation for bleeding complications is recommended.
References
Alternative for Lepirudin B01A
Tinzaparin
Clopidogrel
Ticagrelor
Dipyridamole
Epoprostenol
Edoxaban
Enoxaparin
Cilostazol
Eptifibatide
Apixaban
Iloprost
More
Alternative for Heparin (flush) B01A
Argatroban
Selexipag
Antithrombin III human
Lepirudin
Acenocoumarol

C05B

S01X
Potassium Iodide
Vitamin A
Cyclosporine
Acetylcysteine
Sirolimus
Ascorbic acid

Potential Metabolism Interactions

Substrate-Substrate Interaction：If more than one drug is metabolized by the same CYP, it is possible that its metabolism is inhibited because of the competition between the drugs. That means, it can be useful to lower the dosage of the drugs in the drug-cocktail because they remain longer in the organism than in monotherapy.
Inhibitor-Inhibitor Interaction：Combining two or more inhibitors of one CYP, should be compensated by lowering the dosage of these drugs because the metabolism is reduced and the drugs remain longer in the organism than in monotherapy. Not adapting the dosage bears the risk of even more side effects.
Inhibitor-Substrate Interaction：Combining drugs that have inhibitory effect and are substrates of one particular CYP, should be compensated by lowering the dosage. They rest longer in the organism than in monotherapy. Not adapting the dosage bears the risk of even more side effects.