B.29 Flashcards
Drugs in cancer treatment I (antimetabolite)
Antifolates: Methotrexate, Pemetrexed
Fluoropyrimidines: 5-Fluorouracil, Capecitabine
Deoxycitidine analogs: Cytarabine
Purine antagonists: 6-Mercaptopurine
Classification of antitumor agents
- Cytotoxic antitumor agents
- Cytostatic antitumor agents
- Cytotoxic antitumor agents
- Direct effect on cell proliferation
- Toxic (because there’s no basic difference between the division of normal and malignant cells)
- Relative selectivity (because the malignant cell division happens faster than the normal, but so the fast dividing normal cells are more affected→myelosuppression, GI symptoms, mucositis, alopecia)
- Cytostatic antitumor agents
- Effect by modifying the regulatory systems of cell proliferation
Complications of cytotoxic agents
- Nausea, vomiting
- Diarrhea
- Myelosuppression
- Neutropenia
- Mucositis
- Alopecia
- Pain
- Nausea, vomiting
- Types: acute (within 24h), delayed (after 24h)
- Epidemiology: 30-60% of patients
- e.g.: Cisplatin
- Treatment: Prophylaxis: dexamethasone, NK1-R antagonists; In refractory cases: various groups → olanzapine, D2-R antagonists etc
- Diarrhea
- Casue e.g.: Irinotecan, 5-FU
- interesting fact, in the case of vinca alkaloids, constipation shows because of the effects of the vinca alkaloids on cholinergic neurons
- Treatment: rehydration, constipants (loperamide)
- Myelosuppression
- all patients must be monitored brfore every treatment cycle
- treatment: modifying the protocol, tranfusion, CSFs
- Neutropenia
- Attention to neutropenic fever, rapid antimicrobial therapy necessary
- Antimicrobial prophylaxis: co-trimoxazol (Pneumocystis Jirovecii), Fluconazole (candidiasis)
- Mucositis
- Ulcerative and inflammatory lesions on the GI tract
- Treatment: adequate nutrition and hydration, pain treatment (2% viscous lidocaine, 0.5% doxepin, 0.2% morphine - Americal protocol)
- Alopecia
- Present in 65% of the patients
- reversible, but rarely permanent
- Treatment: preventive: combing, dying and ironing should be avoided, cooling with ice; Post chemotherapy: bimatoprost solution to the edge of the eyelid in case of palpebral alopecia, minoxidil locally
- Pain
- Depending on acute or chronic pain: Acute- start with interventional treatment→strong opioids→ weak opioids→ non-opioid analgestics; Chronic pain- non-opioid analgestics→weak opioids→ strong opioids→ interventional therapy
Drugs in cancer treatment - classification
- Antimetabolites
- Alkylating agents
- Topoisomerase inhibitors
- Mitotic spindle inhibitors
- Antimetabolites
- Antifolates: Methotrexate, Pemetrexed
- Fluoropyrimidines: 5-fluorouracil, Capecitabine
- Deoxycitidine analogues: Cytarabine, Gemcitabine
- Purine antagonists: 6-mercaptopurine, Fludarabine, Cladribine
5-Fluorouracil
MOA: specific for S-phase.
5-FU is uptaken by the cell →it is metabolized to FdUTP (deoxynucleotide analog) and FUTP (nucleotide analog)→FdUTP inhibits thymidylate synthase (no dTMP synthesis)→ inhibits DNA/RNA synthesis→ cell apoptosis. It also inhibits Thymidylate synthase and no dTMP is produced→also leading to apoptosis;
Kinetics: i.v. adm., good distribution in bowel mucosa, BM, liver and brain, metabolized mainly in the liver (CYP2C9), T1/2 rises with dose, it is broken down also by DPD (→the partial or full deficiency of DPD by AR inheritance may lead to severe toxicity);
IND: metastatic colorectal cc - anal and rectal cc combined with radiotherapy (combined with leucovorin), progressive metastatic breast cc, Progressive stomach cc, progressive pancreatic cc, progressive metastatic squamous cell head & neck cc, esophageal cc, cervical cc, renal cell cc;
SEs:
-Cardiac☠ (ischemia/infarct, HF, arrhythmias, angina),
-CNS☠ (disorientation, ataxia, visual disturbances, cerebellar syndrome, hyperammonemic encephalopathia),
-Gastrointestinal☠ (mucositis, stomatitis, esophagopharyngitis, ulcers, diarrhea),
-Myelosuppression⇊ (neutropenia, thrombocytopenia, anemia),
Hand-foot syndrome, Mutagenic, carcinogenic, teratogenic, possible infertility;
Extra: combined with leucovorine it has increased toxicity/cytotoxic effect