Cytotoxic chemotherapy damages DNA or blocks cell division. It kills rapidly dividing cells — cancer cells, but also bone marrow, GI mucosa, hair follicles, and gonads, which explains the classic toxicities. Some drugs act only in one phase of the cell cycle (cell cycle–specific); others act in any phase (cell cycle–nonspecific). Drugs with different mechanisms and toxicities are combined and given in cycles so normal tissue can recover between doses.

Nadir: blood counts fall to their lowest point usually 7–14 days after a dose, then recover before the next cycle.

Supportive drugs

• Antiemetics: 5-HT₃ antagonists (ondansetron), NK₁ antagonists (aprepitant), dexamethasone, olanzapine — given before chemotherapy and scheduled afterward for highly emetogenic regimens
• Myeloid growth factors (filgrastim, pegfilgrastim): shorten neutropenia; bone pain; rare splenic rupture
• Dexrazoxane: anthracycline cardioprotection and extravasation antidote
• Allopurinol or rasburicase: tumor lysis prevention

Contraindications and cautions

• Pregnancy: most antineoplastics are teratogenic, especially in the first trimester — pregnancy test before treatment and effective contraception during and after (duration per drug label). Breastfeeding is generally stopped during chemotherapy
• Severe marrow suppression (e.g., ANC below 1,000–1,500/mm³ or platelets below 75,000–100,000/mm³ — thresholds per protocol) → cycle is delayed or dose reduced
• Doxorubicin: avoid when the lifetime dose limit has been reached or LVEF is reduced
• Fluorouracil and capecitabine: boxed warning (added October 2025) for DPD deficiency — test for DPYD variants before starting unless treatment is urgent; avoid in complete deficiency
• Checkpoint inhibitors: caution with active autoimmune disease or organ transplant
• Live vaccines are contraindicated during chemotherapy; household members may receive most vaccines

Interactions

• Methotrexate + NSAIDs, proton pump inhibitors, penicillins, or trimethoprim-sulfamethoxazole → delayed clearance and toxicity
• Capecitabine + warfarin → elevated INR and bleeding
• Cisplatin + aminoglycosides or loop diuretics → additive nephrotoxicity and ototoxicity
• Many oral targeted drugs are CYP3A4 substrates (interactions with azoles, grapefruit, rifampin, St. John's wort); some need acid (avoid PPIs)
• Tamoxifen efficacy may fall with strong CYP2D6 inhibitors (paroxetine, fluoxetine)
• Anthracycline + trastuzumab → greater cardiotoxicity

Before each dose

1. Verify the order independently with a second qualified nurse: client identity, regimen, cycle and day, dose calculated from height and weight (body surface area) or AUC, route, rate, and lab parameters
2. Check CBC with ANC, platelets, creatinine, liver tests, and electrolytes; hold and notify for results outside protocol parameters
3. Premedicate (antiemetics; for taxanes, dexamethasone and antihistamines); hydration as ordered
4. Organ tests as indicated: LVEF (echo/MUGA) before and during anthracyclines and trastuzumab; pulmonary function for bleomycin; audiometry for cisplatin; magnesium for cisplatin

During administration

• Vesicants (anthracyclines, vinca alkaloids): confirm brisk blood return before and during the push; a central line is preferred for continuous vesicant infusions; stay with the client during peripheral vesicant pushes
• Extravasation (pain, burning, swelling, no blood return): stop the infusion, leave the catheter in place and aspirate, then remove it; do not apply pressure; notify the provider; give the antidote per protocol — dexrazoxane for anthracyclines (cold packs removed at least 15 minutes before), hyaluronidase with warm compresses for vinca alkaloids, cold compresses for anthracyclines; elevate and document
• Hypersensitivity watch in the first minutes of taxane, platinum, and antibody infusions — emergency drugs at the bedside
• Vincristine: dispense in a minibag for IV infusion, labeled "For intravenous use only — fatal if given by other routes"; never in the same area as intrathecal drugs

Ongoing

• Neutropenic fever — temperature ≥ 38.3 °C (101 °F) once, or ≥ 38.0 °C (100.4 °F) sustained over 1 hour, with ANC below 500/mm³ (0.5 × 10⁹/L) or expected to fall below 500: obtain cultures and start IV antibiotics promptly (commonly within 1 hour)
• Bleeding precautions with low platelets: soft toothbrush, electric razor, no IM injections, no aspirin or NSAIDs
• Oral care for mucositis (soft brush, bland rinses such as saline or sodium bicarbonate, no alcohol mouthwash)
• Intake and output, weight, and hydration (cisplatin, cyclophosphamide, high-dose methotrexate)
• Tumor lysis labs in high-risk clients: potassium, phosphate, uric acid, calcium, creatinine
• Checkpoint inhibitors: thyroid tests, glucose, liver tests, cortisol as ordered; ask about diarrhea, cough, and fatigue at every visit

Safe handling of hazardous drugs

• Hazardous drug lists (NIOSH) include most antineoplastics; exposure risks for staff are skin absorption, inhalation, and ingestion
• Two pairs of chemotherapy-tested gloves and a disposable, impermeable gown closed in the back for administration, plus eye/face protection when splashing is possible; a fit-tested respirator for spills or aerosols
• Compounding in a biological safety cabinet or compounding aseptic containment isolator; closed-system transfer devices for administration when the dosage form allows
• Prime IV tubing with a non-drug solution before spiking the bag, or prime in the pharmacy
• Dispose of all contaminated items in labeled chemotherapy waste containers (trace vs. bulk per policy); do not clip or recap needles
• Spills: use the spill kit, full PPE, contain from the outside in, clean with detergent then water, document and report
• Body fluids of treated clients: gloves (and gown if splashing) for at least 48 hours after chemotherapy (up to 7 days for some drugs, per policy); double-flush toilets when lids exist
• Oral chemotherapy is also hazardous: do not crush or split; wear gloves; teach home handling
• Staff who are pregnant, breastfeeding, or trying to conceive follow institutional policy (alternative duty is commonly offered)

• Take your temperature when you feel unwell; call immediately for 38.0 °C (100.4 °F) or higher — do not take acetaminophen first and wait
• Hand hygiene, avoid sick contacts, safe food handling; strict "neutropenic diets" are not required
• Report bleeding, bruising, black stools, shortness of breath, chest pain, severe diarrhea, mouth sores that prevent eating, or confusion
• Take antiemetics on schedule, even before nausea starts; small bland meals
• Hair loss is usually temporary; scalp protection and sunscreen
• Use effective contraception; discuss fertility preservation (sperm or egg banking) before treatment
• Cyclophosphamide: drink plenty of fluids and void often, including at night; report blood in urine
• Oxaliplatin: avoid cold drinks and cold objects for several days after each dose
• Capecitabine: report hand or foot redness, peeling, or pain; moisturize
• Checkpoint inhibitors: report new diarrhea, cough, rash, severe fatigue, headache, or excess thirst even months later; carry the treatment card
• Home safety for 48 hours after treatment: flush the toilet twice with the lid down, wash soiled laundry separately, use condoms (drug can be present in body fluids), and wash hands after using the toilet; store oral chemotherapy away from children

Wrong-route vincristine (intrathecal) is almost always fatal — prevention (IV minibag, labeling, separation) is the only safe strategy.

• Chemotherapy targets rapidly dividing cells: marrow, GI mucosa, hair, gonads; nadir 7–14 days
• Neutropenic fever = emergency: cultures and IV antibiotics within about 1 hour
• Cyclophosphamide → hemorrhagic cystitis (hydrate, mesna); cisplatin → kidneys, ears, nausea
• Doxorubicin → cumulative cardiotoxicity, red urine, vesicant; trastuzumab → heart failure (LVEF)
• Bleomycin → pulmonary fibrosis; vincristine → neuropathy, constipation; IV only
• Methotrexate → leucovorin rescue; 5-FU/capecitabine → DPYD testing; overdose → uridine triacetate
• Extravasation: stop, leave catheter, aspirate, notify, antidote (dexrazoxane / hyaluronidase)
• Checkpoint inhibitors: immune-related colitis, pneumonitis, endocrinopathies → corticosteroids
• Two-person independent verification of dose (BSA) and labs before every dose
• Hazardous handling: double chemotherapy gloves, impermeable gown, CSTD, spill kit, body-fluid precautions 48 hours
• Oral chemotherapy is hazardous too — no crushing, gloves