Pharm: Anticancer Drugs 1 & 2 Flashcards
Describe the 4 basic groups of anticancer drugs.
- Hormonal agents
- Targeted Drugs (mAbs directed at cell surface receptors, NIBs directed at associated RTKs, mTOR inhibitors)
- Action on mitotic spindle
- Action on DNA
When you think DNA damaging agents, think:
Alkylating agents
When you think DNA synthesis inhibitors, think:
Antimetabolites
Are there currently any anticancer agents that are 100% selective for tumor cells and spare the good host cells entirely?
No.
Whereas older drugs’ aim was to kill the tumor cell, many of the newer agents are designed not to kill the tumor, but to:
control growth, thereby making the cancer a lifelong but manageable disease
What is the major problem with new cancer drugs over the conventional type?
They are prohibitively expensive
What are the 5 aims of newer anticancer drugs?
1- Force terminal maturation with no proliferative potential
2- Alter invasive/metastatic potential of tumors.
3- Prevent angiogenesis and thereby tumor growth
4- Produce tumor radio-sensitive or radioprotection of bystander tissues
5- Perturb tumor-host metabolic and immunologic relationship.
What causes nausea and vomiting in chemotherapy pts?
Detection of the drug at the base of the fourth ventricle, by so called “chemo trigger zone), within the gastrointestinal tract itself, and finally through higher order cortical output, relaying the psychological aspects of impending chemotherapy.
What are the rapidly proliferating host cell (noncancerous) populations most adversely affected by chemotherapy?
Myelosuppression (delayed ~ 10 day toxicity)
Lining of oral cavity and GI tract
Hair
What is the most effective way of curing a pt of a solid tumor?
surgical removal (excision)
What is the treatment name for chemotherapy used before other treatment modalities such as surgery or radiation?
neo-adjuvant treatment
If chemotherapy is used after treatments such as surgery or radiation, it is called _______ treatment.
adjuvant treatment
What is the main treatment for systemic diseases such as blood cancers or metastases?
chemotherapy
What treatment modalities are effective when metastasis has not occurred?
radiation or surgery
T/F: systemic chemotherapy for disseminated disease is often only palliative with temporary improvement in quality of life.
True
Give a quick list of toxicities due to cancer therapy (chemo or radio).
Secondary malignancies, organ toxicity, sterility
Explain tumor lysis syndrome and explain in what types of cancers it is most common.
When therapy causes tumor cell lysis, they leak their contents into the circulation, ending up in the kidney, causing damage.
Seen with some cancers of the blood or solid tumors.
What are the biochemical changes to the blood in tumor lysis syndrome?
lysis of tumor cells releases purine nucleic acids, K+ & P
Renal elimination saturated by ^K+, ^P, v Ca2+, & gout.
Uric acid deposited, along with calcium phosphate.
How do you manage tumor lysis syndrome?
hydration, acid/base correction, sodium bicarbonate to alkalinize urine; specific drugs to reduce potential for precipitation
What drug can reduce the production of uric acid in tumor lysis syndrome?
allopurinol
Regarding treatment for tumor lysis syndrome:
What drug speeds the conversion of uric acid to allantoin, a more soluble product that produces less renal damage (no gout)?
Rasburicase
Allopurinol blocks the conversion of hypoxanthine to _________ and (previous blank) to __________ to prevent gout resulting from tumor lysis syndrome.
xanthine; uric acid
Regarding cell cycle specific drugs:
Vinca alkaloids/Taxols are specific to what phase of the cell cycle?
M phase (anti-microtubule)
Regarding cell cycle specific drugs:
Antimetabolites are specific to what phase of the cell cycle?
S - inhibit DNA synthesis
Regarding cell cycle specific drugs:
Podophyllotoxins are specific to what phase of the cell cycle?
S phase and G2- inhibits repair of break after topoisomerase splits dsDNA. Causes damage to DNA
Regarding cell cycle specific drugs:
Bleomycin is specific to what phase of the cell cycle?
G2 phase- induces DNA strand breaks
List the alkylating anticancer drugs.
Major agents are capitalized:
CYCLOPHOSPHAMIDE, BCNU, CCNU, CISPLATIN, MECHLORETHAMINE, MELPHALAN, Busulfan, Dacarbazine, Procarbazine, Ifosfamide, Carboplatin
Can every cytotoxic agent be used against every type of tumor, regardless of what organ it is in?
No
Cyclophosphamide is not active until:
It has been converted by hepatic microsomal enzymes to a 4-hydroxy metabolite which exists in equilibrium with aldophosphamide. These metabolites are delivered to tissues where they undergo further non-enzymatic cleavage to their cytotoxic forms, phosphoramide mustard and acrolein.
How do alkylating anticancer agents work, basically?
Transfer alkyl group to DNA» ssDNA or dsDNA cross-linking resulting in miscoding; strand breakage through guanine excision.
Alkylating agents trap the cell in this cell cycle phase:
G2, act in S phase
Why are alkylating agents best not given IV?
They cause blood vessels to blister (esp. mechlorethamine_
What is an unusual cardiovascular ADE of cyclophosphamide?
congestive heart failure with rapid onset (<2 wks), due to transmural hemorrhage
more common with high doses administered over short interval
In addition to alkylating anticancer agents being bad for your CV system, they also produce these negative side effects:
- CNS: ifosfamide- altered mental status, coma, generalized seizures, cerebellar ataxia
- Lungs: all alkylating agents» fibrosis, dyspnea, cyanosis, pulmonary insufficiency
- 2ndary malignancies, leukemias, and solid tumors
- Tetratogenicity; 1/6 chance of malformed offspring
A metabolite of the alkylating agent cyclophosphamide, acrolein, has these ADEs on the bladder:
severe hemorrhagic cystitis
prevented by good hydration and co-admin of Mesna (drug)
This alkylating anticancer agent can cause renal failure characterized by difficulty in Ca2+ and Mg2+ reabsorption, glycosuria, and renal tubular acidosis.
Cyclophosphamide
What is Mesna, when is it administered, and how does it work?
Mesna is a prophylactic chemoprotectant from hemorrhagic cystitis caused by alkylating anticancer agents. It is administered concurrently with alkylating agents to prevent damage to the bladder.
Complexes with and inactivates the toxic metabolite of cyclophosphamide, acrolein.
In addition to cyclophosphamide being used in chemotherapy for cancer, it is also used for/to treat:
Preparation for allogenic stem cell transplantation
Rheumatoid arthritis (RA) -reserved for pts who have clearly failed DMARDs and anti-cytokine therapy
Does busulfan require metabolic precessing for activity?
What are the ADEs of busulfan use?
No, undergoes spontaneous hydrolysis in aqueous solutions.
Pulmonary fibrosis, GI mucosal damage, Veno-occlusive disease of the liver, impotence, sterility, amenorrhea & fetal malformation