All material is copyrighted and the property of mehlmanmedical.
Copyright © 2020 mehlmanmedical.
Privacy Policy and Terms and Conditions
HY points followed by a quiz at the end
—
Bleomycin
MOA of bleomycin?
- Causes free radical formation –> damages DNA.
When is bleomycin used?
- Part of the ABVD regimen for Hodgkin lymphoma (Adriamycin, Bleomycin, Vinblastine, Dacarbazine).
What’s the most important point I need to know for USMLE about bleomycin?
- Hands-down that it causes pulmonary fibrosis.
- 35F + was treated pharmacologically for Hodgkin disease last year + now has increasing shortness of breath + CXR shows a diffuse reticulonodular pattern; which agent is most likely responsible for this patient’s condition? –> answer = bleomycin.
- Pulmonary fibrosis on USMLE will be described in a vignette as “reticulonodular” or “reticular” pattern seen on CXR and CT. These are the medical terms for “honeycombing.” The latter is often described in resources, but on the USMLE they won’t use this buzzword.
- FEV1/FVC will be normal or increased because fibrosis causes restrictive lung disease.
- Other HY agents for USMLE that cause pulmonary fibrosis are: methotrexate, amiodarone, busulfan, and nitrofurantoin.
Doxorubicin (Adriamycin), Daunorubicin, Hydroxydaunorubicin
MOA of doxorubicin?
- Generates free radicals + intercalates into DNA.
When is doxorubicin used?
- Part of the ABVD regimen for Hodgkin lymphoma (Adriamycin, Bleomycin, Vinblastine, Dacarbazine).
What’s the most important point I need to know for USMLE about doxorubicin?
- Causes dilated cardiomyopathy.
- 44M + started on pharmacologic therapy a couple months ago for Hodgkin disease + now has shortness of breath with exertion + S3 heart sound + dilated cardiac silhouette on CXR; which agent is most likely responsible for this patient’s condition? –> answer = doxorubicin.
What agent can be used to mitigate the toxicity of doxorubicin?
- Dexrazoxane is an agent that chelates free radicals and can help prevent dilated cardiomyopathy associated with doxorubicin.
Busulfan
MOA of busulfan?
- Alkylating agent
When is it used?
- Ablates the bone marrow in those undergoing bone marrow transplantation.
What’s the most important point I need to know for USMLE about busulfan?
- Causes pulmonary fibrosis similar to bleomycin, methotrexate, amiodarone, and nitrofurantoin.
Cyclophosphamide, Ifosfamide
MOA of cyclophosphamide?
- Guanine-N7 alkylating agent
What’s the most important point I need to know for USMLE about cyclophosphamide?
- Causes hemorrhagic cystitis (red urine).
- Toxic metabolite called acrolein is responsible for the bladder toxicity.
- Mesna is a cytoprotective agent that contains thiol (-SH) groups and is used to mitigate the bladder toxicity. If Mesna isn’t listed, N-acetylcysteine (normally used for acetaminophen toxicity) can rarely be correct (also contains -SH groups).
Nitrosoureas (Carmustine, Lomustine)
MOA of nitrosoureas?
- DNA cross-linking agents
What do I need to know for USMLE?
- That they can treat brain tumors.
- And just know the MOA.
Cisplatin
MOA of cisplatin?
- DNA cross-linking agent.
When is it used?
- Can be used as a treatment for testicular cancer.
What’s the toxicity of cisplatin?
- Neurotoxicity (known as “toxic neuropathy”). This is asked on the 2CK Neuro shelf, where a patient receiving cisplatin has miscellaneous neuropathy, and the answer is “toxic neuropathy,” which means neuropathy secondary to agents (such as cisplatin or vincristine).
- Ototoxicity (neurosensory hearing loss; tinnitus; vertigo).
- Nephrotoxicity (acute tubular necrosis).
What do I need to know for USMLE that’s most HY?
- Treatment of toxicity is first with chloride diuresis (i.e., 0.9% NaCl normal saline).
- After chloride diuresis, amifostine is used.
- Amifostine scavenges free radicals.
Microtubule inhibitors
- Not all used for anti-cancer, but all very HY to memorize so I’m grouping them here.
- Vincristine
- Vinblastine
- Taxanes (Paclitaxel, Docetaxel)
- Griseofulvin
- Colchicine
- -Bendazoles (Mebendazole, Albendazole)
Which is the odd one out?
- Taxanes (Paclitaxel, Docetaxel) are the odd ones out. They hyper-stabilize microtubules (i.e., prevent disassembly), whereas all of the other agents prevent formation of microtubules.
- Because microtubule assembly/disassembly occurs during mitosis, these work during M-phase of the cell cycle.
What do I need to know that’s HY for each drug for the USMLE?
- Vincristine is neurotoxic. It’s used as part of CHOP for non-Hodgkin lymphoma (CHOP –> Cyclophosphamide, Hydroxydaunorubicin, Oncovin [Vincristine], Prednisone).
- Vinblastine is used as part of the ABVD regimen for Hodgkin lymphoma (Adriamycin, Bleomycin, Vinblastine, Dacarbazine).
- Taxanes (Paclitaxel, Docetaxel) hyper-stabilize (i.e., prevent disassembly of) microtubules, whereas the others prevent assembly.
- Griseofulvin is the treatment for tinea capitis (“cradle cap”; i.e., fungal infection of the scalp). This is asked explicitly on the FM shelf for 2CK.
- 9M + circular area of alopecia and scaling of the scalp; treatment? –> answer = “oral griseofulvin for patient only.” (a wrong answer is for patient + close contacts).
- Colchicine is used as one of the treatments for acute gout, pseudogout, and pericarditis.
- -Bendazoles are used for helminth infections. Mebendazole is classically used for nematode (round worm) infections (e.g., ascariasis); albendazole is for neurocysticercosis.
—
