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95 Cards in this Set
- Front
- Back
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** What is the most common/ important side effect of chemotherapy?
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Bone marrow suppression
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Why is bone marrow suppression the most common side effect of chemotherapy?
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Bone marrow cells divide rapidly because there is a normally high growth fraction and most anticancer drugs target tissues with a high growth fraction
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Are cats or dogs more sensitive to developing bone marrow suppression from chemotherapy?
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Cats
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Are large or small dogs more sensitive to developing bone marrow suppression from chemotherapy?
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Small dogs-must reduce doses in dogs weighing less than 10-15 kg
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What is the clinical result of myelosuppression?
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Varying degrees of peripheral blood cytopenias.
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What is the 1-10-100 rule?
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The rate of blood cell line half lives-
RBCs=110 days (Dogs), 70 cats Platelets=5-10 days Granulocytes=4-8 hrs |
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What type of cytopenia is first apparent in animals with myelosuppression?
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Granulocytopenia occurs first followed by thrombocytopenia.
-Granulocytes live shortest, then platelets |
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True or false. Anemia is a common feature of myelosuppression.
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False, Anemia is rare and usually only mild to moderate.
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What is the most common and most serious dose-limiting cytopenia related to chemotherapy toxicity?
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Granulocytopenia
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Why is it important to wait adequate time between administering chemotherapy?
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Need to allow bone marrow to fully recover b/w treatments
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What is the nadir?
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Time of the lowest granulocyte count
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What type of chemotherapy agents cause granulocytopenia most rapidly, cell cycle phase-nonspecific or specific?
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Cell cycle phase specific
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True or false. Nadirs in small animals usually occurs between 2-10 days.
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False, nadirs occur between 3-14 days
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How long does it take neutrophil counts to rebound after chemotherapy?
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1-3 days following treatment
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**What treatment must be performed when an animal has a neutrophil count less than 1000/ul?
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Patients are at risk for sepsis and require monitoring and prophylactic antibiotic treatment.
-These are grade 3 & 4 neutropenias |
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What clinical signs are usually associated with an animal with stage 4 neutropenia (<500 neutrophils/ul)?
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Fever & sepsis
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Why does chemotherapy cause sepsis that can be overwhelming & life-threatening?
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-GI epithelium desquamates from chemotherapy
-Enteric bacteria gain access to circulation via damaged GI mucosa -Low numers of circulating neutrophils are incapable of phagocytosis and bacterial killing -Bacteria gain access to numerous organs via blood |
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What bacteria cause sepsis after chemotherapy?
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Enteric bacteria
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What are the clinical signs of sepsis?
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depression, anorexia, nausea/vomiting/diarrhea, shivering, FEVER
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True or false. Chemotherapy-induced thrombocytopenia rarely causes clinical bleeding.
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True
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How can you prevent sepsis as a side effect of chemotherapy?
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Monitor CBC and platelet count weekly or at the time of the expected nadir
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What should you do when a chemotherapy is known to produce severe neutropenia?
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Consider prophylactic antibiotics prior to and during the nadir.
-Trimethoprim sulfa -Enrofloxacin or ciprofloxacin |
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Why is trimethoprim sulfa the preferred antibiotic to prevent sepsis after chemotherapy?
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-Well tolerated, good owner compliance
-Spares anaerobic (normal) flora in bowel |
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What dogs should not be given trimethoprim sulfa to prevent sepsis after chemotherapy?
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Black and tan dogs (dobermans, rottweilers etc.)
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*What is the therapy for animals with neutropenia (<1500-2000/ul) that are afebrile and asymptomatic?
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-Postpone myelosuppression for 1 cycle
-Restart offending drugs at ~75-80% previous dose after neutrophil count has normalized -+/- administer oral antibiotic until neutropenia resolves |
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When are antibiotics necessary for animals with neutropenia after chemotherapy?
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Not necessary until neutrophil count drops to 1000-1500 /ul or lower
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What should be done when a patient is neutropenic, febrile and showing clinical signs (e.g. vomiting, diarrhea, trembling, dehydration)?
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-Assumer fever is of bacterial origin (give antibiotics)
-Halt chemotherapy -Consider blood cultures, although rarely helpful -Give IV antibiotics w/ broad coverage e.g. enrofloxacin plus ampicillin +/- metronidazole -Provide adequate fluids IV -Provide any other symptomatic support-antiemetics, vitamins, parenteral nutrition -Rule out other pathologies |
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How long does it normally take a fever to respond to antibiotics?
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Fever usually respond within 24 hrs if not consider antibiotic change
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What type of bacteria are you targeting when trying to treat chemotherapy associated sepsis?
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Gram negative bacteria-enteric bacteria
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What are the 3 types of gastrointestinal toxicity?
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1. Nausea/vomiting (most important and commonly seen)
2. Mucositis/diarrhea 3. Constipation |
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What is a bad side effect of cisplatin in dogs?
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Nausea/vomiting-why use carboplatin instead, less side effects
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True or false. Vincristine doesn't usually cause vomiting as a side effect.
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False, 25-30% of dogs will vomit for 1-2 days duration
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True or false. Mucositis in the oral cavity is rarely a problem in veterinary medicine, but diarrhea is more common.
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True
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What chemotherapy is known to cause constipation? Why?
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Vincristine, impairs gut motility so consider use of a prokinetic such as metaclopramide
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What are 3 ways that drugs can cause nausea/vomiting?
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1. Direct stimulation of the CNS vomiting center or chemoreceptor trigger zone
2. Serotonin release in the gut a problem---> vagal stimulation---> nausea,vomiting 3. Indirect via drug-induced GI mucosal inflammation and damage (mucositis) |
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Why does mucositis result from chemotherapy?
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Rapidly dividing (high GF) intestinal mucosa is a prime target of chemotherapy. The result is death and sloughing of the GI epithelium
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What are the clinical signs of mucositis?
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Gastroenteritis
-Diarrhea (w/ blood & can be severe) -Vomiting |
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**How do you prevent nausea/vomiting when performing chemotherapy?
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Pretreatment followed by several days of antiemetics
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What antiemetics are commonly used?
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-Metoclopramide (Reglan)-not a good drug for preventing chemotherapy nausea
-Ondansetron-don't be hesitant to use! Usually only takes 1-2 days of dosing, prevents nausea -Dolasetron (Anzamet) -cost effective as injectable -Maripotant (Cerenia) |
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*What antiemetic is currently used at OSU?
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Inject Dolasetron IV at the time chemotherapy is given and send home 4 days of maripotant (Dogs) or 4 days of oral ondansetron (cats).
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What can be done to prevent constipation as a side effect of chemotherapy? Mucositis?
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Can't prevent mucositis or constipation other than dose reduction, but metoclopramide and ranitidine may improve motility
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*What is the therapy for nausea/vomiting caused by chemotherapy?
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-Parenteral antiemetics
-Antacid therapy -NPO -Return to bland diet when vomiting subsides |
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True or false. Enteric coating agents such as Pepto-bismol and Kaopectate are commonly used for diarrhea.
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False, questionable efficacy do not use
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What should be done for severe diarrhea?
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Hospitalize for IV fluid support and IV antibiotics-metronidazole
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What can be done to prevent oral mucositis?
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Flush mouth with dilute chlorhexidine solution
-more of a problem secondary to oral radiatin -Broad spectrum antibiotics e.g. clavamox, enrofloxacin, trimethoprim-sulfa |
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What should you do if an animal has mucositis and there's a putrefying odor?
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Suggests anaerobic bacterial growth and metronidazole should be given
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What can be done for constipation?
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Provide fiber
May require enema Prokinetic meds-metoclopramide |
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What type of hypersensitivity reaction do animals have with anaphylactic drug reactions?
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Usually require prior drug sensitization-classic type I hypersensitivity
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True or false. Some drugs (e.g. doxorubicin) can cause anaphylactic shock without prior exposure and triggers a spontaneous mast cell reaction, this is considered an anaphylactic reaction.
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False, this is a type IV hypersensitivity-not true anaphylaxis
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*What chemotherapy is most likely to induce hypersensitivity reactions? Why?
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L-asparaginase because asparaginase is a bacterial protein of E. coli
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What are the clinical signs of hypersensitivity reactions?
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-Generalized wheals, urticaria & pruritus
-Head shaking may be earliest indication due to ear pruritus Ear pinna turn red -Vomiting, urination, defacation, tachycardia, pale mm, collapse -Usually happens within 1 hr |
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How can you prevent hypersensitivity reactions in animals that are known to be sensitive?
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-Pretreat with antihistamine e.g. diphenhydramine minutes ahead of chemotherapy
-Corticosteroids (IV) e.g. dexamethasone 5 minutes before chemotherapy |
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How can you prevent hypersensitivity reactions to L-asparaginase?
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After the first treatment, administer L-asparaginase IM, IP, or SQ but never IV
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How can you prevent hypersensitivity reactions to Doxorubicin?
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Give by slow (>15-20 minutes) or longer infusion
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*What is the drug of choice in a true hypersensitivity crisis to a chemotherapy medication?
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Epinephrine
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What do you do when a patient has a hypersensitivity reaction that's not a crisis?
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-Discontinue drug administration if possible, wait 30-60 mins, then resume after medicating.
-Diphenhydramine IM or if needed IV -Dexamethasone-excellent choice |
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What are the 3 types of dermatologic toxicity seen with chemotherapy?
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1. Local tissue necrosis secondary to drug extravasation.
2. Delayed hair growth/alopecia 3. Hyperpigmentation |
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What is the most important dermatologic toxicity associated with chemotherapy?
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Local tissue necrosis
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**What agents induce the worst perivascular reactions?
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Severe w/ doxorubicin and taxol, moderate to severe w/ vinca alkaloids.
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What are the clinical signs of local tissue necrosis from vinca alkaloids?
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Erythema, pruritus, ulceration
Animals lick site continuously Self trauma begins 1-7 days post injection, ulcers develop by 14 days |
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When do you notice local tissue necrosis from doxorubicin? How?
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Pitting edema of injected limb-noticeable by 7 days
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What may be a sequela of doxorubicin extravasation?
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Skin grafting/limb amputation
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What dogs are most commonly affected by alopecia from chemotherapy?
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Dogs with prolonged anagen (growth) phase of the hair cycle
-Includes poodle, maltese, and some terriers=dogs that don't normally shed |
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True or false. Whiskers usually fall out on dogs and cats on chronic chemotherapy.
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True
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Where do animals normally get hyperpigmentation from chemotherapy?
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Chin and muzzle
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What are 3 ways to prevent local tissue necrosis when administering chemotherapy?
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1. ALWAYS use a butterfly or indwelling catheter
2. Check and double check patency of the line by demonstratable blood return 3. If in doubt use another vein, its ok to send animal home untreated if can't hit vein |
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True or false. Hyperpigmentation and alopecia in animals undergoing chemotherapy can be easily prevented.
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False, there is no prevention
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What should you do if an anticancer drug is injected perivascularly?
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-Aspirate through butterfly or catheter to try to remove drug
-DO NOT inject SQ fluids to try to dilute -spreads agent and creates more tissue damage |
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What can you do if Doxorubicin is injected perivascularly?
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Inject 10Xs the amount of dexrazoxane IV
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What can you do if a vinca alkaloid was injected perivascularly?
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Immediately infiltrate the area of extravasation with hyaluronidase. Cold compress
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What can you do when an animal breaks out in chronic ulcers from chemotherapy?
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-No specific therapy
-Bandage to prevent self-mutilation -Debridement/graft as necessary -Vinda-induced ulcers will heal in 2-3 months |
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What can you do for animals with delayed hair growth/alopecia?
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-Coat, shirt
-Sunburn/insect protection |
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What are the 2 types of cardiotoxicity related to chemotherapy?
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-Acute:ECG changes, hemodynamic alterations-reversible
-Chronic: cardiomyopathy, dose-related; irreversible |
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**What drug induces the most severe cardiac toxicity?
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Doxorubicin
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What anticancer drug can cause cardiac toxicity at high doses?
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Cyclophosphamide
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**What 4 anticancer drugs are the most nephrotoxic?
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1. Cisplatin-used exclusively in dogs.
2. Streptozocin-previously limited its use in small animals 3. Methotrexate 4. Doxorubicin in cats |
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What can you do to monitor animals receiving drugs that may have nephrotoxicity?
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Watch BUN and creatinine levels
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What are the 3 clinical signs of renal failure?
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1. Vomiting
2. Dehydration 3. Oliguria (small amounts of urine excretion) |
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What is azotemia?
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Increased nitrogen compounds-creatinine & blood urea nitrogen
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How can you prevent nephrotoxicity?
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-Avoid nephrotoxic drugs in animals w/ pre-existing azotemia
-Administer cisplatin using a renal-protective protocol -Avoid other nephrotoxic compounds (e.g. NSAIDS, aminoglycosides) |
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What is the therapy for nephrotoxicity?
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-Standard therapy
-Improvement should be seen within 3 days -Stop drug |
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True or false. Hepatoxicity is a common side effect of chemotherapy in small animals.
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False, rare in small animals and difficult to prove
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What 3 drugs cause neurotoxicity?
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1. Vincristine
2. 5-Fluorouracil 3. Cisplatin |
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**What commonly used anticancer agent is toxic to the urinary bladder?
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Cyclophosphamide
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**What are the clinical signs of cyclophosphamide causing sterile hemorrhagic cystitis?
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1. Pollakiuria (Frequent urination)
2. Hematuria 3. Dysuria (painful urination) 4. Stranguria (painful excretion of urine due to spasmodic contraction of the urethra and bladder) |
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**What do you see on urinalysis of an animal with sterile hemorrhagic cystitis of cyclophosphamide?
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Many RBCs (hematuria), usually without signs of infection-urine is sterile
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True or false. Cats are more commonly affected by sterile hemorrhagic cystitis of cylophosphamide.
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False, dogs more commonly affected
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How can you prevent sterile hemorrhagic cystitis of cyclophosphamide?
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-Give cyclophosphamide in morning and encourage animal to urinate during the day
-Can salt food on cyclophosphamide days to increase water intake -Give single dose of Furosemide IV concurrently w/ cyclophosphamide injection to promote diuresis |
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**What is the treatment for non-severe sterile hemorrhagic cystitis of cyclophosphamide?
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-Discontinue cyclophosphamide
-Symptomatic: Corticosteroids, parasympatholytics (e.g. propantholine) to decrease straining, sympatholytics to decrease sphincter spasm -Oxybutynin (antispasmodic specifically active on bladder) |
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**What can be done to treat severe, portracted (months) cases of sterile hemorrhagic cystitis of cyclophosphamide?
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May respond to dilute formalin infusion into the bladder.
-Last resort, requires anesthesia -Can also use 50% DMSO in saline 2-3 Xs weekly-safer and easier to do -Instill into bladder w/ a mushroom catheter for 30-60 mins, then drain |
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**What 2 drugs are contraindicated in the cat?
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Cisplatin
5-Fluorouracil |
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Why is cisplatin not used in cats?
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Causes acute dyspnea and death within 48-96 hrs after treatment. Pulmonary vasculitis causes pulmonary edema
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True or false. It is okay to give cats carboplatin but not cisplatin.
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True
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*Why is 5-fluorouracil contraindicated in the cat?
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Fatal CNS toxicity
DO NOT USE ON CATS |
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When is bleomycin used?
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In cats with oral squamous cell carcinoma
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