Cancer pharmacology Flashcards
Bone marrow suppression
Also called “myelosuppression”, used interchangeably
Highly toxic to bone marrow because cells of this tissue are rapidly proliferating and in an active state
Reduces circulating neutrophils, erythrocytes, and platelets
High risk for infection (low neutrophils), bleeding (low platelets), and anemia (low erythrocytes)
Neutropenia count
Normal neutrophil count = 2500-7000 cells/mm3
Neutropenia = absolute neutrophil count (ANC) < 500/mm3
Neutropenia
Neutrophils → WBCs that fight infection
Incidence and severity of infection increase with a decrease in circulating neutrophils
Most cytotoxic drugs will cause a rapid onset of neutropenia with rapid recovery
Begins to develop 2-3 days after dosing
Lowest neutrophil count (called the Nadir) occurs between day 10 and day 14
Patients are highest risk during the Nadir
Neutropenia precautions
Neutrophil counts must be monitored carefully → chemotherapy should be held until neutrophil counts improve
High risk of developing infection from normal flora of the body
*** low neutrophils hide signs of infection → usual signs of infection such as pus, abscesses, and infiltrates may not be present
Fever is the main sign of infection in someone with low neutrophils
Neutropenia nursing considerations
EDUCATION →
-the risks of developing neutropenia and their risk for infection
-minimize contact with others
-avoid crowds
-report a fever immediately to the health care provider
-Hand washing
-Regular cleansing of skin and oral cavity
When hospitalized, placed in isolation
Frequently monitored for fever
Foods that have high risk to carry pathogens should be avoided (meat, vegetables, fruit)
Pan culture patient (Blood cultures, urine cultures, wound cultures, sputum cultures) as soon as patient shows signs of infection
Thrombocytopenia
Reduced circulating platelets
Increased risk in bleeding
Common signs → bleeding gums and nose bleeds
Normal platelet count = 150,000-300,000 cells/mm3
Thrombocytopenia = Platelet count < 150,000/mm3
Thrombocytopenia nursing considerations
Patients should not take medications that induce bleeding (for example, aspirin, anticoagulants, etc)
Patients should avoid vigorous tooth brushing and must be careful when shaving
Procedures such as IV insertions should be done very carefully. Subcutaneous and intramuscular injections should be avoided
Nurses must be cautious when applying blood pressure cuff, as overinflation may cause bruising
Anemia
Reduction in circulating erythrocytes
Anemia is less common than thrombocytopenia and neutropenia→ erythrocytes have a longer life span (120 days) allowing for recovery before levels fall too low
Monitor for signs of anemia, fatigue, pallor, shortness of breath
Digestive Tract Dysfunction: Stomatitis
Inflammation of the oral mucosa
Develops 2-3 days after start of chemotherapy
May continue up until > 2 weeks after treatment has stopped
Begins as inflammation and can progress to ulceration
Can lead to infection
Causes pain which affects eating, speaking, and swallowing
Assess oral mucosa regularly
Weigh patient and monitor intake
Digestive Tract Dysfunction: Diarrhea
Destruction of epithelial lining of the intestine affects absorption of nutrients and fluids, causing diarrhea
This impairs nutrition, hydration, and may lead to infection due to impaired skin integrity
Alopecia
Also known as “hair loss”
Results from injury to hair follicles, which rapidly proliferate
Occurs with most cytotoxic medications
Begins 7-10 days after start of treatment and peaks at 1-2 months
Hair will grow back 1-2 months after treatment ends
Not life threatening, however very common fear in cancer patients
Patients should be warned of the potential for hair loss
Wigs and hair pieces should be chosen prior to the hair loss occurring
Reproductive Toxicity
Cytotoxic medications interfere with early embryo development
May cause fetal malformation and death → more common in first trimester
Research shows after 18 weeks, risk is very low to the fetus
Chemotherapy can cause irreversible sterility in men
Men should be provided with education on sperm banking
Cytotoxic meds can also affect the ovaries leading to amenorrhea and menopausal symptoms
Extravasation
is the leakage of drug from the blood vessel into the surrounding tissues
Extravasation can cause pain, infection, loss of mobility, and in severe cases necrosis and sloughing
If the patient shows signs of extravasation (redness, swelling, blisters at the site), the infusion should be stopped immediately
Carcinogenesis
Cytotoxic drugs can cause cancer
By damaging DNA, chemo drugs can promote cancer to develop
This may occur years after treatment
More likely to occur with Alkylating Agents
Cyclophosphamide
Cause alkylation of DNA which destroys the DNA in cancer cells
Prevent cells from being able to repair themselves
Cell-cycle phase non-specific → can act during any phase of the cell cycle
More toxic to rapidly dividing cells compared to cells in the inactive G0 state because alkylation of DNA is more lethal when cells are actively trying to replicate DNA
Cyclophosphamide is the most common Alkylating Agent
Non vesicant → can therefore be administered orally and intravenously
Commonly causes bone marrow suppression, nausea/vomiting, alopecia, and can also cause acute bladder injury and hemorrhagic cystitis
