Patients taking nadroparin calcium are at risk of heparin-induced or immune-related severe thrombocytopenia, with occasional thrombosis. These usually occur between days 5 and 21 of treatment (most likely on day 10).Laboratory Monitoring During Treatment is necessary during using Nadroparin Calcium Injection in order to ensure the safety.
This may occur earlier in patients with a history of heparin-related thrombocytopenia. Therefore, it is necessary to systematically look for the above risk factors in the medical history. In addition, the risk of recurrence of these symptoms after re-administration of heparin may or may not persist for several years. Therefore, platelet count monitoring is necessary regardless of the indication or dose used.
There are three possible situations:
Patients without a history of heparin-related thrombocytopenia
Platelet counts were determined before treatment and then twice a week for 21 days. Thereafter, for cases requiring prolonged heparin treatment, platelet counts were measured weekly until the end of treatment.
In fact, any significant drop in platelet counts (up to 30%-50% of baseline values), even at critical values, should be considered a red flag. If the platelet count is low, the following actions should be taken in any case:
- Immediately verify the platelet count;
- Withhold heparin therapy if platelet counts are confirmed to have decreased or have decreased further on controlled tests;
- If prophylactic antithrombotic therapy needs to be continued at this time, oral anticoagulant therapy can be used instead.
Patients with a history of heparin-related thrombocytopenia
Regardless of the time interval between the previous occurrence of heparin-associated thrombocytopenia and the resumption of heparin, and regardless of the previous heparin dosage form, relapse can occur within a short period of time and is usually very severe. An in vitro platelet aggregation test can be used, but it is not sufficiently sensitive to have absolute predictive value.
Therefore, the following measures need to be taken:
- Use other antithrombotic drugs, whether or not possible,
- If a decision is made to use nadroparin calcium, clinical and laboratory monitoring should be strengthened from the first day (measurement of platelet counts at least once a day), treatment duration should be shortened as much as possible, and anti-vitamin K therapy should be started immediately if necessary.
- Use special blood tests.
Heparin-related thrombocytopenia in the acute phase
In all cases, this condition was treated as an emergency.
In this case, it is not necessary to deal with the results of the platelet in vitro agglutination test, because this test can only be done in some special laboratories, and the results will be delayed for at least a few hours. Reduces the duration of heparin therapy associated with the disease and the risk of thrombosis.
- If necessary to continue heparin therapy: In this exceptional case, try switching to a different low molecular weight heparin. Nonetheless, prolonged or exacerbated thrombocytopenia and/or thrombosis may occur even if the in vitro cross-agglutination test is negative.
- If continued use of heparin can be avoided: Immediately replace oral anticoagulants, and use antiplatelet preparations only after a balance has been achieved with antivitamin K preparations.
- Replace heparin therapy with oral anticoagulants: Step up clinical and laboratory monitoring (prothrombin time by INR) to control the effects of oral anticoagulants.
Heparin should be maintained long enough to ensure that the INR remains within the desired therapeutic range eg, between 2 and 3, because of the latency period before the maximum antivitamin K effect is reached.
- Determination of anticoagulant factor Xa activity
Effective treatment: Determination of anticoagulant factor Xa activity to determine individual patient sensitivity, especially in cases of failure to clinical treatment, bleeding, or renal impairment; Blood is usually collected between 3 and 4 hours after injection on the second day of treatment. And the acceptable therapeutic range is usually 0.5-1.0 IU anti-Xa/ml.