Hematological and Oncological Medications

Therapy used to Treat Cancer

Chemotherapy can cause suppression of rapidly reproducing cells, including bone marrow suppression.  This can result in decreased red blood cells, white blood cells, and platelets, all manufactured in the bone marrow.  It is most likely to be seen with chemotherapy (versus radiation), with the lowest counts (the nadir) usually at 7-10 days after therapy initiation.  Leukopenia is a decrease in total circulating white blood cell count (<4,000/mm³) and neutropenia is a decrease in circulating neutrophils (usually <1500/mm³).

Brachytherapy is an internal radiation treatment that is ingested, injected into the bloodstream, or implanted (eg, seeds, wires) directly into or near the tumor.  Clients with permanent brachytherapy implants emit low doses of radiation over an extended time period and typically do not pose a risk of radiation exposure to others.  However, those with temporary brachytherapy (eg, sealed cervical radium implants) require safety precautions because the client emits radiation while the source is in place and poses a risk of exposure to others.

The plan of care for a client with temporary brachytherapy implants should include the following interventions:

• Use appropriate shielding (eg, place client in a lead room, use lead shields and apron) to limit exposure. 
• Limit each person’s time of exposure to the client (eg, cluster care, 30 minutes per shift) 
• Assign all staff members involved in the client’s care their own dosimeter badge to measure radiation exposure, and instruct them to wear it during every shift.
• Instruct the client to remain on bed rest, and use caution when repositioning to avoid device dislodgement.
• Maximize distance from the client (eg, 6 ft [1.8 m] is recommended).

A potential complication of chemotherapy is acute tumor lysis syndrome (TLS), a rapid release of intracellular components into the bloodstream.  Massive cell lysis releases intracellular ions (potassium and phosphorus) and nucleic acids into the bloodstream.  Catabolism of the nucleic acids produces uric acid, resulting in severe hyperuricemia.  Released phosphorus binds calcium, producing calcium phosphate mixture but lowering serum calcium levels.  Both calcium phosphate and uric acid are deposited into the kidneys, causing renal injury.

The therapeutic effect of allopurinol (Zyloprim) is to decrease hyperuricemia caused by TLS.  Laboratory values of significance in TLS include rising blood uric acid, potassium, and phosphate levels, with decreasing calcium levels.

Selective estrogen receptor modulators (eg, tamoxifen) have differential action in different tissues (mixed agonist/antagonist).  In the breast, they block estrogen (antagonist) and are therefore helpful in inhibiting the growth of estrogen-receptive breast cancer cells.

However, tamoxifen has estrogen-stimulating (agonist) activity in the uterus, resulting in excessive endometrial proliferation (endometrial hyperplasia).  This hyperplasia can eventually lead to cancer.  Irregular or excessive menstrual bleeding in premenopausal woman or any bleeding in postmenopausal women can be a sign of endometrial cancer .  Due to its estrogen-agonist actions, tamoxifen also poses a risk for thromboembolic events (eg, stroke, pulmonary embolism, deep vein thrombosis). Clients with breast cancer take tamoxifen for several (5-10) years to prevent recurrence.  Therefore, monitoring for life-threatening side effects is very important.

Antineoplastic

Cisplatin is an antineoplastic medication that can cause renal toxicity.  The client’s elevated BUN (normal 10-20 mg/dL [3.6-7.1 mmol/L]) may be due to dehydration (prerenal disease) or decreased kidney function.  The creatinine is also elevated (normal for males: 0.6-1.2 mg/dL [53-106 µmol/L]; normal for females: 0.5-1.1 mg/dL [44-97 μmol/L]), an indication of kidney injury.

Immunosuppressants

TNF inhibitor drugs (eg, etanercept [Enbrel], infliximab [Remicade], adalimumab [Humira]) block the action of TNF, a mediator that triggers a cell-mediated inflammatory response in the body.  These drugs reduce the manifestations of rheumatoid arthritis (RA) and slow the progression of joint damage by inhibiting the inflammatory response.  The medication causes immunosuppression and increased susceptibility for infection and malignancies.

Major adverse effects of biologic disease-modifying TNF inhibitor drugs (eg, etanercept, infliximab, adalimumab) include severe infections and bone marrow suppression.  TB reactivation is a major concern.  Therefore, all clients must receive a TST to rule out latent TB.

Anticoagulants

Factor Xa inhibitors (eg, rivaroxaban [Xarelto], edoxaban, apixaban) are anticoagulants used to prevent and treat venous thromboembolism.  Factor Xa inhibitors are being prescribed more frequently than other oral anticoagulants (eg, warfarin), as they have a lower risk of bleeding and require less ongoing monitoring (eg, PT/INR).

Clients prescribed rivaroxaban should be educated to avoid taking over-the-counter medications or supplements that increase bleeding risk, such as NSAIDs (eg, aspirin), garlic, and ginger.  The combined effects of rivaroxaban and other anticoagulants may greatly increase the risk of uncontrolled bleeding (eg, epidural, intracranial, gastrointestinal) and hemorrhage

The nurse should instruct clients receiving factor Xa inhibitors (eg, rivaroxaban, edoxaban, apixaban), which are anticoagulants, to avoid taking additional medications or supplements with anticoagulant effects (eg, NSAIDs, garlic, ginger).  The combined anticoagulant effects increase the risk for uncontrolled bleeding and hemorrhage.

Enoxaparin (Lovenox) is a low molecular weight heparin (LMWH) that may be prescribed for up to 10-14 days following hip and knee surgery to prevent deep venous thrombosis.  

Discharge teaching for the client on enoxaparin therapy includes:

1. Pinch an inch of skin upwards and insert the needle at a 90-degree angle into the fold of skin.
2. Continue to hold the skin fold throughout the injection and then remove the needle at a 90-degree angle.
3. Mild pain, bruising, irritation, or redness of the skin at the injection site is common.  Do NOT rub the site with the hand.  Using an ice cube on the injection site can provide relief 
4. Avoid taking aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), and herbal supplements (Ginkgo biloba, vitamin E) without health care provider approval as these can increase the risk of bleeding 
5. Monitor complete blood count to assess for thrombocytopenia.

Supplements

Ferrous sulfate is an oral iron supplement prescribed to prevent or treat iron deficiency anemia, which occurs when the body lacks sufficient iron, an essential mineral in the formation of new RBCs.  Low iron levels may result from malabsorption, insufficient intake, increased requirements (eg, pregnancy), or blood loss.  The nurse should avoid administering calcium supplements or antacids with or within 1 hour of ferrous sulfate because calcium decreases iron absorption.

See Adverse Effects of Herbal Supplements HERE