Amlodipine-induced immune thrombocytopenia

Calcium Channel Blocker-Induced Thrombocytopenia in the Intensive Care Unit: A Rare Presentation and Review of the Literature

Patients with thrombocytopenia may report easy bruising, abnormal bleeding, and fatigue. Drug-induced thrombocytopenia has been reported with a variety of medications, most commonly heparin products, sulphonamides, carbamazepine, nonsteroidal anti-inflammatory drugs, anti-epileptic drugs, and chemotherapy. We present the case of a 58-year-old female with severe thrombocytopenia attributed to a calcium channel blocker (CCB) overdose, a very rare cause of thrombocytopenia. We discuss the diagnostic work-up and management in the intensive care unit and perform a literature review.

Durable remission of thrombotic thrombocytopenic purpura in the setting of pembrolizumab therapy

BACKGROUND

There is a small but growing number of thrombotic thrombocytopenic purpura (TTP) cases attributed to immune checkpoint inhibitor therapy, with nivolumab and ipilimumab therapy being the most frequently described in the literature.

STUDY DESIGN AND METHODS

This report evaluates the course of a patient with a history of metastatic adenocarcinoma of the lung who developed TTP following treatment with the PD-1 inhibitor Pembrolizumab. The patient was treated with six sessions of therapeutic plasma exchange and appeared to be in remission. Exacerbation occurred 4 days later, and seven more sessions of plasma exchange were performed along with four total doses of Rituximab, and a steroid taper with monitoring of platelet counts and ADAMTS13 activity.

RESULTS

His platelet count recovered to a peak of 318,000 UL with an ADAMTS13 activity of 77% at the time of discharge. The patient has been following up regularly for outpatient testing with no TTP relapse as of the completion of this report.

DISCUSSION

This is one of a few cases of Pembrolizumab-associated TTP reported in the literature with successful complete remission following treatment. Plasma exchange in this setting may be an especially beneficial therapeutic intervention because of the removal of both the anti-ADAMTS13 antibody as well as the immune system upregulating anti-PDL1 monoclonal antibody with replacement of ADAMTS13 from donor plasma. Longer duration of plasma exchange and monitoring for normalization of ADAMTS13 levels in addition to platelet count before cessation of treatment may improve durable remission rates in this entity.

Perindopril/amlodipine-induced thrombotic microangiopathy

This is the first report on a case of perindopril/amlodipine-induced thrombotic microangiopathy (TMA) syndrome. A 48-year-old female was admitted complaining of nettle rash all over the body, bloody urine, and weakness shortly after starting antihypertensive therapy with perindopril/amlodipine. Shortly thereafter, she developed pronounced hemiparesis, somnolence, and sensorimotor aphasia. Laboratory findings were compatible with microangiopathic hemolytic anemia and thrombocytopenia. She was diagnosed with TMA. Cessation of perindopril/amlodipine therapy and treatment with plasma exchange and systemic corticosteroids resulted in full recovery. Very seldom perindopril/amlodipine may cause hematologic abnormalities, probably through an immunological mechanism, but there were no reports of causing TMA so far. In our case, the symptoms began shortly after the start of perindopril/amlodipine use. The clinical course of TMA in the case was compatible with TMA related to an acute, immune-mediated drug reaction. The most important thing is to promptly recognize TMA and its induction by a drug because distinctive treatment and cessation of the suspected drug can prevent severe outcome, as it was avoided in our patient.

Simvastatin and amlodipine induced thrombocytopenia in the same patient: double trouble and a literature review

WHAT IS KNOWN AND OBJECTIVE

Drug-induced thrombocytopenia (DITP) may be a fatal adverse reaction to many drugs. It is often misdiagnosed as primary immune thrombocytopenia (ITP), and thus diagnosis can be delayed and patients can be treated inappropriately. Amlodipine a calcium-channel blocker, and simvastatin, a statin, have very rarely been implicated in DITP. We report on an investigation of the causal relationship of amlodipine and simvastatin with thrombocytopenia occurring in the same patient, and review the literature.

CASE SUMMARY

We present the case of a 78-year-old female hypertensive diabetic patient with three successive DITPs. The first attack of acute severe thrombocytopenia occurred after a 2-week course of amlodipine, and was initially misdiagnosed as ITP. Her platelet count normalized after the amlodipine was discontinued. The second attack followed her restarting simvastatin 3 weeks later. She had stopped it 2 months earlier having previously taken it for over 5 years. Again, she recovered once the simvastatin was discontinued. The third DITP attack occurred when she accidently took a single dose of amlodipine 9 months later.

WHAT IS NEW AND CONCLUSION

We provide clear evidence of a causal association of amlodipine with thrombocytopenia, and probable evidence of a causal association of simvastatin with thrombocytopenia. This is the first reported case of DITPs occurring with two of the most widely prescribed drugs in the same patient. Many hypertensive patients need to take multiple drugs in order to achieve their treatment goals and this increases their risk of drug-induced adverse reactions and makes identification of the causal drug (or drugs) extremely difficult.