Keywords

Introduction

As advances in cancer therapies continue to improve, a growing number of patients are living with cancer. As such, there is an increased probability for critical care providers to encounter cancer patients within the intensive care unit (ICU). Furthermore, oncologic patients require increased utilization of resources in the ICU due to disease-related complications and/or treatment-related adverse events [124]. Metabolic complications present difficult challenges in the management of critically ill cancer patients [72]. Immunosuppression, secondary to the cancer itself or cancer-related therapies (e.g., chemotherapy, corticosteroids, hematopoietic cell transplant, etc.), places patients at an increased risk for infection. In addition, many new chemotherapy and targeted therapies have numerous adverse effects that not only increase the risk for ICU admission but require multiple other therapies to help manage these side effects.

Medication regimens for critically ill cancer patients are complex. Many patients require a large number of concomitant medications to manage the critical, oncologic, and supportive care issues encountered. Accordingly, avoidance and detection of drug-drug interactions and overlapping adverse effect profiles is of high concern. The intent of this chapter is to provide critical care practitioners with an overview of non-chemotherapy medications that are frequently encountered during the care of a critically ill cancer patient in hopes of increasing awareness of such therapy. It should be emphasized that this chapter is not all-inclusive in respect to the medications discussed and details provided, and clinicians are advised to seek additional information as applicable. In addition, medication doses are reflective of a patient with normal renal function and clinicians should refer to drug dosing references for organ dysfunction adjustments unless otherwise noted.

Antimicrobial Agents

Gram Positive Agents

Risk for methicillin resistant staphylococcus aureus (MRSA) and vancomycin resistant enterococcus (VRE) as shown in Table 1 may be heightened in the oncology population due to increased exposure to the healthcare setting and antimicrobials [11]. While initial therapy of patients with febrile neutropenia may not require coverage for MRSA, empiric antibiotic regimens for all patients progressing to sepsis or septic shock or those patients with additional risk factors should be broadened to include an agent targeting aerobic gram positive cocci [102]. For MRSA, consider early addition of vancomycin, linezolid, or daptomycin. For VRE, consider early addition of linezolid or daptomycin. Selection of a specific agent should be based on patient-specific (e.g., end organ function) as well as an infection-specific factors (e.g., source of infection). As mentioned in Table 2, use of linezolid may compromise bone marrow function; this does not preclude use of linezolid in patients with pancytopenia or thrombocytopenia, but it does justify a risk-benefit analysis inclusive of alternative options prior to therapy initiation [126]. Consider an infectious diseases (ID) consult if MRSA or VRE is isolated in the context of systemic infection [11, 43]. Discontinuation of MRSA and/or VRE therapy should be considered if a pathogen is not identified within 48–72 h of obtaining all pertinent cultures.

Table 1 Considerations for MRSA/VRE coverage
Table 2 Oncologic considerations for select antibiotics

Gram Negative Agents

Empiric intravenous (IV) antibiotics with anti-pseudomonal coverage should be initiated immediately in high-risk patients with febrile neutropenia and may include piperacillin/tazobactam, ceftazidime, cefepime, meropenem, or imipenem-cilastatin [11, 43]. Unfortunately, frequent exposure to antimicrobials and repeated hospitalization result in greater risk of acquiring resistant gram-negative organisms [114].

Oncology patients are at increased risk of infections with gram negative organisms from translocation from the gastrointestinal (GI) tract, particularly in patients with mucositis or graft versus host disease (GVHD). Risk of acquiring multi-drug resistant (MDR) gram negative organisms is increased by the use of prophylactic fluoroquinolones in patients with chemotherapy-induced neutropenia [33, 71, 78]. Initial empiric coverage of extended spectrum beta lactamase (ESBL) organisms and carbapenem resistant enterobacteraciae (CRE) should be based on patient-specific factors including prior exposure of antipseudomonal prophylaxis for febrile neutropenia patients and prior infections or microbiologic culture results. Double antipseudomonal gram-negative coverage may be warranted in patients with a history of P. aeruginosa or other MDR organism colonization or in hemodynamically unstable patients. Combination therapy with an aminoglycoside should be preferred in patients recently treated with fluoroquinolone prophylaxis (Table 2) [11]. Consider an infectious disease consult for patients with multidrug resistant organisms (MDRO).

Antiviral Agents

Oncology patients, particularly those with hematologic malignancy and/or history of HCT, are at risk for viral infections as a result of their underlying malignancy, chemotherapy, prolonged neutropenia, impaired cell-mediated immunity, and/or treatment complications (e.g., GVHD) [136]. Infection with herpes simplex (HSV), herpes zoster (HZ), cytomegalovirus (CMV), and respiratory viruses (e.g., respiratory syncytial virus [RSV]) are of prominent concern. A review of the pharmacologic options for management of these infections is presented in Table 3.

Table 3 Oncologic considerations for select antivirals
Fig. 1
figure 1

How to calculate CrCL as mL/min/kg with modified Cockcroft and Gault equation for Foscarnet dosing. (Reference: (1) Foscarnet package insert)

Many oncology patients admitted in the ICU may already be receiving antiviral prophylaxis against herpes simplex virus (HSV) and herpes zoster (HZ) with acyclovir or valacyclovir. In addition to HSV/HZ, another common pathogen observed in patients with hematologic malignancy/post-HCT is cytomegalovirus (CMV). CMV is a beta herpes virus with a seroprevalence in the United States (US) of around 60% [130]. Typically, most people are asymptomatic when primary infection with CMV occurs and then the virus enters a latent infectious state in mononuclear leukocytes. Reactivation can occur in many instances, but in relation to the oncology patient population, this can be seen during times of immunosuppression (e.g., chemotherapy administration) and critical illness as well as in the elderly [34]. Prophylaxis against CMV is not routine, given the toxicity profile of traditional anti-CMV therapy (i.e., ganciclovir and foscarnet); rather a strategy of pre-emptive monitoring has been adopted with treatment reserved for patients with presumed or documented infection [136]. Recently, the Federal Drug Agency (FDA) approved letermovir for CMV prophylaxis in HCT CMV seropositive recipients. Given the more acceptable toxicity profile of this agent and the morbidity/mortality associated with CMV infection, use of letermovir will likely increase in hopes of preventing CMV reactivation [84].

Despite preventive strategies and increased awareness, respiratory viral infections may occur, with RSV, influenza, parainfluenza, and human metapneumovirus responsible for the majority of cases. Progression to lower respiratory tract infection often presents as dyspnea and hypoxia, which can prove fatal. Unfortunately, limited options currently exist for managing these viral infections (e.g., neuraminidase inhibitors for influenza, ribavirin for RSV) and therapy is primarily supportive. Studies are needed to further elucidate high-risk patients and determine efficacy of novel antiviral agents [23]. Other viruses that may be notable for complications in cancer patients include adenovirus, human herpesvirus 6 (HHV6), polyomaviruses (BK and JC), and Epstein-Barr virus (EBV).

Antifungal Agents

Antifungal coverage should be considered in febrile neutropenic patients on broad-spectrum antibiotics who have had a persistent fever for 4–7 days and no identified fever source [43]. Antifungal therapy should also be considered in critically ill ICU patients (regardless of the presence or absence of malignancy) with suspected infection who do not improve after 72 h of broad-spectrum antibiotics [110]. For empiric coverage of Candida, use of an echinocandin (anidulafungin, micafungin, or caspofungin) is preferred, especially in patients who have been recently treated with other antifungal agents, or if Candida glabrata or Candida krusei is suspected from previous culture data [47, 114].

Hematologic malignancy patients with prolonged neutropenia, status post allogeneic HCT, and/or chronic corticosteroid exposure (e.g., GVHD) are at risk for invasive aspergillosis infections [101]. Posaconazole or voriconazole are often utilized for prophylaxis against invasive aspergillosis in high-risk patients [29, 139, 146]. In the absence of contraindications (i.e., organ dysfunction, adverse effects) or development of a breakthrough infection, antifungal prophylactic regimens should be continued following ICU admission. For patients who develop breakthrough invasive aspergillosis while receiving prophylactic azole therapy, therapeutic drug monitoring (TDM) should be performed to assess adequacy of the current regimen, if available; however, the patient will likely need to be switched to another class of medications. Voriconazole remains the treatment of choice for Aspergillus infections (Table 4). However, if the patient is unable to tolerate voriconazole therapy, isavuconazonium or the liposomal formulation of Amphotericin B (AmB) are appropriate alternative options for initial therapy. Posaconazole can be considered for salvage therapy [101].

Table 4 Oncologic considerations for select antifungals

Severe and prolonged immunosuppression also places patients at risk for mucormycosis infections. Posaconazole has been shown to be the most effective antifungal for prophylaxis against mucormycosis; of note, voriconazole is not active against mucormycosis. Liposomal AmB is recommended by the guidelines as the treatment of choice for mucormycosis infections; however, isavuconazonium has recently been approved with the indication as well [10]. Posaconazole is reserved for salvage therapy. Surgical interventions combined with medical treatments have been associated with higher survival rates in patients with mucormycosis when compared to pharmacologic therapy alone [28].

Cancer patients are commonly on numerous medications and chemotherapies that may interact with concomitant azole therapy. Azoles are potent inhibitors and substrates of cytochrome p450 enzymes; therefore, clinicians must be diligent about evaluating for drug-drug interactions (DDIs). In addition, azoles can cause QTc prolongation. Clinicians should monitor closely and optimize electrolytes, particularly in patients on multiple QTc prolonging medications.

Pneumocystis Jiroveci Pneumonia

Prophylaxis and treatment for pneumocystis jiroveci pneumonia (PJP) should be considered in patients with risk factors (neutropenic, immunosuppressed, long-term or high-dose steroids) who are not improving on standard antimicrobial therapy. Prophylactic therapy is usually given to oncologic patients receiving certain types of chemotherapy (i.e., alemtuzumab, purine analogs), HCT patients, or patients on immunosuppression with chronic and/or high-dose steroids. The choice of prophylaxis (e.g., sulfamethoxazole-trimethoprim [SMZ-TMP], pentamidine) is typically based on patient- and/or disease-specific factors (Table 5). Prophylaxis is usually continued until immunosuppression therapy has been discontinued and counts have recovered (absolute neutrophil count [ANC] >1000), CD4 > 200, or according to the specific chemotherapy regimens as noted on the package insert or protocol [32].

Table 5 Oncologic considerations for Pneumocystis jiroveci pneumonia (PJP)

For treatment of PJP infection, sulfamethoxazole-trimethoprim (SMZ-TMP) remains the drug of choice (Table 5). However, certain circumstances preclude use of SMZ-TMP, such as an allergy to sulfa medications, the desire to avoid agents that may suppress the bone marrow (e.g., HCT patients pre-engraftment), or persistent SMZ-TMP-related hyperkalemia. In such situations, alternative agents such as clindamycin/primaquine should be considered.

Antiepileptics

Seizures are a common neurologic complication in oncologic patients, secondary to primary brain tumors, metastases, radiation toxicity, and metabolic abnormalities [57]. Selection of an antiepileptic drug (AED) warrants special consideration in the oncologic patient due to interactions with chemotherapy, side effects, and unique mechanisms of certain brain tumors. Enzyme inducing anticonvulsants such as phenytoin may lead to insufficient serum levels of concomitantly administered chemotherapy. Conversely, enzyme inhibiting anticonvulsants such as valproate may lead to toxic levels of chemotherapy [17]. AEDs that are substrates for P-gp (phenobarbital, carbamazepine, lamotrigine, topiramate, and felbamate) may result in insufficient intraparenchymal levels [88].

Patients with brain tumors are more prone to refractory epilepsy, requiring the use of multiple AEDs with different mechanisms. With the introduction of more well-tolerated AEDs, many practitioners are avoiding enzyme inducers as first-line agents [88]. While non-CYP-450 enzyme-inducing AEDs such as levetiracetam, gabapentin, and lamotrigine may be preferable in cancer patients receiving chemotherapy, levetiracetam may be preferred as an initial option in the ICU as it is available for IV administration, does not appear to be affected by P-gp expression, and has favorable pharmacokinetic properties (Table 6) [57, 142].

Table 6 Oncologic considerations for seizures

Immunosuppressants

Recipients of a HCT, particularly allogeneic HCT, require immunosuppression to prevent GVHD [149]. Tacrolimus, sirolimus, or cyclosporine are often utilized for GVHD prophylaxis (Table 7). Similar to the approach in solid organ transplant patients, these medications are managed within a narrow therapeutic window in attempt to decrease both the risk of GVHD as well as toxicities of therapy. Additionally, practitioners should remain cognizant of DDIs with these agents [1].

Table 7 Oncologic considerations for immunosuppressants

Corticosteroids are universally utilized immunosuppressants in oncology patients. Often times, corticosteroids are included in different chemotherapy regimens, especially to treat diseases such as diffuse large b-cell lymphoma or acute lymphoid leukemia. High-dose corticosteroids are also utilized to treat a wide range of complications in cancer patients, including but not limited to GVHD, diffuse alveolar hemorrhage (DAH), idiopathic pulmonary syndrome (IPS), and spinal cord compression (SCC) (Table 7). Collaboration between the oncology and critical care teams is recommended when initiating or stopping corticosteroids in the ICU to avoid untoward interactions with ongoing oncologic treatments.

Antifibrinolytic/Antihemophilic Agents

Diffuse Alveolar Hemorrhage (DAH)

Prognosis in patients with DAH secondary to cancer therapy or sepsis is poor [39]. Pulse dose corticosteroids (methylprednisolone 1–2 mg/kg/day) with or without antifibrinolytic therapy has been used in practice but has not been consistently associated with reductions in ICU or hospital mortality, ventilator days, or ICU and hospital length of stay in the literature [77, 113, 143]. Treatment with steroids or antifibrinolytic therapy can be considered in patients at high risk of rapid clinical deterioration or death (Table 8). Agents such as recombinant factor VIIa have been used to achieve hemostasis in non-hemophiliac patients with DAH [100]. Additionally, a case series of six patients successfully used intrapulmonary factor VII as adjunctive treatment for DAH with doses ranging from 30 to 60 mcg/kg [12]. The potential benefit of antifibrinolytic and antihemophilic therapies must be weighed against the risk of thrombotic events [150].

Table 8 Oncologic considerations for bleeding in the ICU

Thrombocytopenia

Spontaneous bleeding complications due to thrombocytopenia are common in the critically ill oncologic patient population [75]. Most patients can be managed by observation and supportive care alone. Use of antifibrinolytic agents have been used in emergency treatment of severe thrombocytopenia-associated bleeding to reduce transfusion requirements without increased risk in thromboembolic events (Table 8) but have not been shown to decrease mortality [7].

Disseminated Intravascular Coagulation (DIC)

Routine use of aminocaproic acid, tranexamic acid and recombinant FVIIa in patients with cancer-related DIC is not recommended. Practitioners may consider use of tranexamic acid in patients with therapy-resistant hyperfibrinolytic DIC bleeding (Table 8). Platelet transfusion to maintain platelets >50 × 103/L, and transfusion of fresh frozen plasma (15–30 ml/kg) with careful monitoring, is the primary therapy in patients with DIC and active bleeding [134].

Gastrointestinal (GI) Bleeding

A large randomized control trial (RCT) is currently underway to examine the use of tranexamic acid for the treatment of GI bleeding [118].

Thrombolytics

Hepatic sinusoidal obstruction syndrome (SOS), previously referred to as veno-occlusive disease (VOD), is a potentially life-threatening complication with a wide-ranging incidence. Severe SOS is associated with a mortality rate greater than 80% [27]. SOS is characterized by a prothrombotic, hypofibrinolytic state as a result of endothelial damage and hepatocellular injury to sinusoidal endothelial cells. Hallmark symptoms include weight gain, painful hepatomegaly, fluid retention/ascites, and hyperbilirubinemia; the reported incidence varies in part due to variable definitions and evaluated populations [36]. SOS is a complication that occurs typically within 3 weeks of a myeloablative HCT but can also be observed in patients with risk factors of pre-existing liver disease, total body irradiation or abdominal/liver radiation, or exposure to certain hepatotoxic drugs, such as inotuzumab or gemtuzumab (list of VOD/SOS risk factors is not all-inclusive) [27, 36]. Defibrotide was FDA approved in the United States in 2016 for the treatment of severe hepatic SOS after publication of a pivotal phase III trial [117]. Its proposed mechanism of action is to reduce endothelial cell activation and injury and promote restoration of the thrombo-fibrinolytic balance [116]. Due to the severity of illness associated with SOS, many patients are transferred to the ICU for continued management and administration of defibrotide (Table 9).

Table 9 Oncologic considerations for thrombolytics

Uric Acid Reducing Agents

Over 50% of oncologic patients with high-risk for tumor lysis syndrome (TLS) require ICU admission, and nearly 1/3 of those will present with acute kidney injury (AKI). Clinicians should be familiar with the management of hyperuricemia to help preserve renal function. Hyperuricemia results from the rapid release and catabolism of intracellular nucleic acids either spontaneously or in response to chemotherapy in patients with a high tumor burden. Patients who are considered high risk for TLS should receive rasburicase over allopurinol (Table 10) [25].

Table 10 Oncologic considerations for uric acid reduction

Hypercalcemia of Malignancy/Hypercalcemia Management

All patients presenting with hypercalcemia of malignancy should be given IV crystalloids at 1–2 ml/kg/h to restore intravascular volume and promote calciuresis. For patients that are fluid restricted due to other co-morbidities (e.g., heart failure), consider concomitant diuresis with a loop diuretic if necessary. Symptomatic patients presenting with abdominal pain, confusion, weakness, and electrocardiogram (EKG) changes may require a bisphosphonate +/− calcitonin. Critical care practitioners should be cognizant of all prior therapy given in order to avoid duplicating therapy and the potential development of hypocalcemia (e.g., recent bisphosphonate or denosumab administration) (Table 11).

Table 11 Oncologic considerations for hypercalcemia of malignancy

Interleukin-6 Receptor Antagonists

Chimeric antigen receptor (CAR) T-cell therapy induces rapid and durable clinical responses in many types of cancer but is associated with unique, acute toxicities that can be fatal. This includes both cytokine release syndrome (CRS) and cytokine-related encephalopathy syndrome (CRES). IL-6 therapy may be warranted in patients exhibiting signs and symptoms of toxicity, particularly those requiring ICU care. IL-6 receptor antagonists are indicated in patients with grade 2 and greater CRES and grade 3 and 4 CRS, and may be considered in those with grade 1 CRES and/or persistent grade 1 or 2 CRS [91].See Table 12 for considerations for IL-6 therapy for CRS or CRES.

Table 12 Oncologic considerations for treatment of cytokine release syndrome or cytokine related encephalopathy syndrome

Growth Factors

Colony stimulating factors (CSF) are recommended to be administered in a prophylactic manner when the risk of febrile neutropenia (FN) with a given chemotherapy regimen is 20% or higher [127]. The American Society of Clinical Oncology (ASCO) and National Comprehensive Cancer Network (NCCN) recommend primary prophylaxis for FN with CSFs based on factors associated with the disease, chemotherapy regimen, patient risk, and treatment intent (curative vs. palliative). Secondary prophylaxis may be warranted in patients who have FN or a dose-limiting neutropenic event [31, 127]. Additionally, CSFs may be used to reduce the length of hospitalization and time to neutrophil recovery, for HCT mobilization, and to reduce the risk of infection in patients with intermittent/persistent neutropenia status post HCT. Of note, the medical record of oncology patients admitted to the ICU should be evaluated for prior CSF administration as such therapy my confound interpretation of leukocytosis (Table 13).

Table 13 Oncologic considerations for growth factors in the ICU

Thrombopoietin and thrombopoietin mimetics are FDA approved for the treatment of chronic immune thrombocytopenia; these agents may also be helpful off label to increase the platelet count in patients with thrombocytopenic disorders [66, 74, 76]. The management of thrombocytopenia in patients with increased bleeding risk (e.g., post-surgical), chemotherapy-induce thrombocytopenia, and/or promotion of platelet engraftment after HCT are some examples of off-label uses for thrombopoietin agents, such as romiplostim (Table 13) [83, 86, 96, 128].

Antidotes

The toxicity profiles of chemotherapy regimens are often severe and adversely affect patients’ quality of life. Although most symptoms can be managed with supportive care (see Table 1 in Chap. 16, “Complications and Toxicities Associated with Cancer Therapies in the Intensive Care Unit”), there are times when treatment interruptions or reversal are necessary.

For reversal of toxicities or overdose, infusion of antidote should be started as soon as possible (Table 14).

Table 14 Antidotes for critically Ill oncologic patients