Chemotherapy Order Verification (2) Flashcards
BSA calculation
BSA (m^2) = sqrt [ (height in cm x weight in kg) / 3600)
At least ______________ have to verify the chemo order
At least 2 pharmacists
7 steps of chemo order verification
- cancer diagnosis
- What regimen is patient receiving?
- What cycle is patient receiving?
- Laboratory assessment
- Dose calculation
- Check DDIs
- Consider additional supportive care medications
Step 1 of order verification
Consider - what is the cancer diagnosis?
-the type of cancer, and the stage of that cancer is important
-there are different dosing protocols and hold parameters based on the particular type of cancer and stage
Step 2 of order verification
Consider - what regimen is the patient receiving?
-consider - is the regimen appropriate for the type and stage of cancer
-what is the schedule of drugs in that regimen
-where in the regimen is the patient today (at which point of the cycle)
These things are important to consider because agents are scheduled/spaced out specifically throughout the regimen to limit toxicity and maximize efficacy
Step 3 of order verification
Consider - what cycle of chemotherapy is the patient on
-if it is not their first cycle - think about how they tolerated the last cycle, what was their nadir like?
-consider dose adjustments based on toxicities or changes in organ function from previous cycle - consider needing to extend cycle (low ANC for example, extended nadir)
-consider cumulative dose caps for certain drugs (doxorubicin and bleomycin)
-consider potential for hypersensitivities (increased risk with additional cycles with carboplatin)
Step 4 of order verification
consider laboratory assessment
-assess organ function and drug clearance: CrCl, total bilirubin, transaminases
-Assess hematological parameters: ensure adequate recovery from previous cycle
Step 5 of order verification
Dose calculation
-most chemo doses are based on BSA
-some are body weight based (particularly more common in pediatrics)
-some agents are fixed doses (typically intrathecal agents)
-some are based on AUC (more common in stem cell transplants)
-remember that some drugs have dose capping
(e.g. vincristine - max 2 mg)
-Dose based on intent:
if treating to cure - give highest dose
if palliative treatment - may want to use lower doses to lower toxicity
Chemo dosing for pediatric patients
BSA can be used for older children
But, BSA overestimates dosing for young children and infants…
-for those < 0.6 m^2 or < 15 kg … use weight based dosing
(convert from mg/m^2 to mg/kg … different conversion factors for different drugs)
Note - intrathecal therapy is fixed dosing - this fixed adult dose can be used for all patients age 3 and up
Step 6 of order verification
Look for DDIs
-review chemo and non chemo therapy
consider dose adjusting or delaying therapy if their are agents that may increase chemo toxicity (hold those agents, then start … e.g. methotrexate & PPIs or NSAIDs, vincristine & azole antifungals)
Or there can be increased toxicity of the non-chemo agent … e.g. warfarin toxicity increased with 5-FU and capecitabine (increased INR) - lower warfarin dose or switch to different drug
Step 7 in order verification
Consider what supportive care medications are needed along with chemotherapy…
-antiemetics
-anti-diarrheals (irinotecan, topotecan, 5-FU)
Pre-medications to prevent hypersensitivities…
-corticosteroids (dexamethasone)
-anti-histamines (diphenhydramine, famotidine)
-antipyretics (acetaminophen)
-emergency medication for anaphylaxis (epinephrine)
Chemotherapy protectants…
-leucovorin (with high dose methotrexate)
-MESNA (cyclophosphamide, ifosfomide)
Infection prophylaxis…
-colony stimulating factors (with prolonged nadir)
-bacterial prophylaxis - quinolone antibiotics
-PCP prophylaxis - bactrim
-fungal prophylaxis - fluconazole, voriconazole
-herpes simplex, varicella zoster: acyclovir
