Topic 5: Drugs that affect the immune and hematological systems Flashcards
(184 cards)
Antimetabolites
Antagonists analogue
- antineoplastic antimetabolites are cell-specific analgouges. Inhibit cellular growth by interfering w/synthesis/actions of the compounds critical to cellular reproduction: vitamin folic acid, purines, pyrimidines (DNA, RNA)
- Two mechanisms: falsely substituting for purines, pyrimidines, folic acid, or inhibit critical enzymes involved in synthesis/function of those compounds
- S phase of cell cycle
Folic acid antagonism
Methotraxate is an analogue of folic acid
- Inhibits action of dihydrofolate reductase (enzyme that converts folic acid to its active form folate needed for synthesis of DNA)
- DNA not produced and cell dies
Pyrimidine antagonism
Floxuridine and fluorouracil are synthetic analogues of uracil, and cytarabine is a synthetic analogue of cytosine
- Capecitabine is a prodrug of fluorouracil and is converted to that drug in the liver and other body tissues. Can be given orally
- Incorporating themselves into the metabolic pathway for synthesis of DNA & RNA and thereby interrupting synthesis of both of these nucleic acids
Antimetabolites Indicatons
Tx of variety of solid tumors and some hematologic cancers
- used in combination chemo regimens to enhance overall cytotoxic effect
- Methotrexate also for Tx of severe cases of psoriasis (skin) rheumatoid arthritis
- oral/topical can be used for low-dose maintenance/palliative (noncurative) cancer therapy
Antimetabolites adverse effects
- Hair loss
- N/V
- Diarrhea
- myelosuppression
- Major toxicity includes: neurologic, cardiovascular, pulmonary, hepatobiliary, GI, genitourinary, dermatologic, ocular, otic, metabolic toxicity
- most common: fever, malaise
- metabolic toxicity: tumor lysis syndrome
- severe but reversible for of dermatologic toxicity (palmar-plantar dysesthesia or paresthesia)
Antimetabolites interactions
Administration of one antimetabolite drug with another that causes similar toxicities may result in additive toxicities
Methotrexate (Folate antagonist)
- Useful for Tx of solid tumors (breast cancer, head and neck, and lung cancers & for management of acute lymphocytic leukemia and non-Hodgkin’s lymphomas
- immunosuppressive activity, it inhibits lymphocyte multiplication, so it’s useful in Tx of rheumatoid arthritis
- its combined immunosuppressant and antiinflammatory properties make it useful for Tx of psoriasis
- high dose associated w/severe bone marrow suppression always given in conjunction w/the “rescue” drug leucovorin (antedote)
- injectable, oral (tablet) forms
- preservative free injectable required for intrathecal (into subarachoid space) administration, in Tx of cancers
Loucovorine
Rescue drug for methotrexate.
- Antidote for folic acid antagonists
- body produces active folic acid via metabolic steps utilizing enzyme dihydrofolate reductase. Because methotrexate inhibits this enzyme, healthy cells die due to lack of folic acid. By giving Loucovorine (which is rapidly converting to the active form of folic acid), it provides the body w/active folic acid, which prevents death of normal cells
Pyrimidine antagonists Fluorouracil (5-FU) (Efudex, Adrucil)
- parenteral formulations
- Variety Tx regimens, including palliative Tx of cancers of the colon, rectum, stomach, breasts, and pancreas
- also used in adjuvant setting in Tx of breast and colorectal cancer
Nursing process: Assessment for Antineoplastic drugs
- physical assessment
- bowel/bladder patterns
- neurologic status
- heart sounds
- heart rhythm
- breath sounds
- lung function
- exam skin/mucosa (turgor, hydration, color, temp.)
- s/s fear/anxiety, insomina, irritability, shakiness, restlesness, palpitations
- past/present abilities for ADL
- pain assessment
- pattern of pain
- note oral, pharyngeal, esophageal, abdominal pain; painful swallowing; epigastric/gastric pain; achiness in joints or lower extremities; numbess, tingling, burning sensation, sharp pain in extremities
- lab tests (electrolytes, minerals, vitamins, uric acid, RBC, WBC, platelets/clotting & bleeding time, renal function (BUN, creatinine, serum uric acid, urine creatinine clearance) hepatic function (AST, ALT, LDH, bilirubin), cardiac enzymes
- assess for tumor markers
Nursing assessment for altered nutritional status and impaired oral mucosa
- s/s of altered nutrition w/focus on weight loss, abnormal serum protein-albumin and blood urea nitrogen (BUN) levels, weakness, fatigue, lethargy, poor skin turgor, pale conjunctiva
- oral mucosa for S/S stomatitis, difficulty swallowing, taste changes, viscous saliva, dryness, cracking, and/or fissures w/or w/out bleeding of the mucosa
Nursing assessment for effects on the GI mucosa
- bowel sounds
- presence of diarrhea, urgency, abdominal cramping
- presence of blood in stool/consistency, color, odor, amount
- N/V (acute, delayed, anticipatory; if V occurs, determine color, amount, consistency, frequency, odor, blood
Nursing assessment for alopecia
- pt’s views, concerns, emotions about hair loss
- need to prepare for hair loss
Nursing assessment for bone marrow suppression
- S/S of anemia or decrease in RBCs, hemoglobin level, & hematocrit (pallor, oral mucus membranes, conjunctiva; fatique, lethargy, loss of interest, SOB, inability to concentrate)
- S/S leukopenia (Decrease WBCs, and/or absolute neutorphil count) fever, chills; tachycardia, abnormal breath sounds; productive cough w/purulent, green/rust colored sputum; change in urine color; lethargy, fatigue, acute confusion
- S/S thrombocytopenia (decrease in thrombocytes <100,000) and platelet clotting factors; unusual bleeding (petechiae; purpura; ecchymosis; gingival (gum) bleeding, excessive bleeding from punture sites, joint pain, blood in stool, urine, V; loss of function of extremities; decrease in BP/elevated pulse
For possible sterility, teratogenesis, and damage to ovaries with amenorrhea: in adult male patients, asses?
Female?
Male: baseline reproductive history w/attention to sexual functioning, fathering of children, past/current reproductive or sexual problems
Female: in addition to those already mentioned, inquire about fertility, menstrual/childbearing history, age of onset of menses and menopause
(Antineoplastic) With cell cycle-specific drugs what should the nurse assess for?
Document allergies, cautions, contraindications, drug interactions
- most antimetabolite drugs do not produce severe emesis (vomiting)
- Pentostatin & some pyrimidine analogues have emetic potential, so perform baseline GI functioning
- folate antagonists not likely to cause emesis, but are associated w/GI abnormalities (ulcers, stomatitis). Since given parenterally (IV) assess peripheral access areas or central venous sites to prevent risk for damage to surrounding tissue, joints, and tendons. Assess every hour for redness, swelling, heat, or pain PRN
Antineoplastic drug: Topoisomerase I Inhibitor Mechanism of action
Semisynthetic analogues of the compound camptothecin (these drugs referred to as Camptothecins)
- Inhibit DNA function in S-Phase by binding to topoisomerase I complex (complex normally allows DNA strands to be temporaily cleaved and then reattached in a critical step called religation)
- binding retards the religation process and results in DNA strand break
Antineoplastic drug: Topoisomerase I Inhibitor Indications
- Tx of ovarian and colorectal cancer
- Irinotecan approved for Tx of metastatic colorectal cancer, small-cell lung cancer, and cervical cancer
Antineoplastic drug: Topoisomerase I Inhibitor Adverse effects (Irinotecan [Camptosar])
- Hematologic effects
- severe diarrhea (cholinergic diarrhea). Treated w/atropine
- delayed diarrhea may occur 2-10 days after infusion of irinotecan
- diarrhea can be severe & life-threatening must be treated aggressively with loperamide
- N/V (supportive care including IV rehydration and antimetic drug therapy)
Antineoplastic drug: Topoisomerase I Inhibitor Interactions with Irinotecan (Camptosar)
- Laxatives and diuretics NOT given due to risk of worsening dehydration
- severe cardiovascular toxicity, thrombosis, pulmonary embolism, stroke, acute fatal MI when Irinotecan is given w/fluorouracil and leucovorin
- only injectable form
Antineoplastic drug: Topoisomerase I Inhibitor nursing assessment
- hematologic adverse effects
- baseline WBC
- continual assessment of GI tract due to potential irinotecan-related cholinergic diarrhea
Before chemo assess patients for the presence of
1) genetic markers of oral cancer
2) genetic determinants of testosterone or estrogen metabolism
3) genetically linked enzyme system abnormalities
Premedication with antimetics give?
30-60 minutes BEFORE administration of the antineoplastic to help reduce N/V, prevent dehydration& malnutrition, and promote comfort
Antineoplastic patient teaching
- OTC medications to avoid: aspirin, ibuprophen, combination of these)
- measures to prevent infection
- frequent skin care
- measures to minimize oral mucosal breakdown
- daily regiment to increase urinary health (cranberry)
- discuss options for alopecia (hair loss)
- methotrexate: report N/V, fever, sore throat, muscle aches, and pains, unusual bleeding. Avoid alcohol, salicylates, NSAIDs, exposure to sunlight or ultraviolet light. Alternative contraceptive measures for 3 months or longer