Discuss five (5) mechanisms used to reduce toxicity of anticancer drugs.

Here are the answers to your long answer questions: 1. Discuss five (5) mechanisms used to reduce toxicity of anticancer drugs. Anticancer drugs often have significant side effects due to their non-selective action on rapidly dividing cells. Mechanisms to reduce this toxicity include: Targeted Therapy: These drugs are designed to specifically interfere with molecular targets (e.g., receptors, enzymes) that are crucial for cancer cell growth and survival, while having minimal effects on healthy cells. This specificity reduces off-target toxicity. Example:* Monoclonal antibodies like trastuzumab target the HER2 receptor, or small molecule inhibitors like imatinib target specific tyrosine kinases. Supportive Care and Rescue Therapy: This involves administering medications to prevent or alleviate the side effects of chemotherapy. These agents protect normal tissues from damage. Example:* Antiemetics (e.g., ondansetron) for nausea and vomiting, colony-stimulating factors (e.g., filgrastim) to prevent neutropenia, and cytoprotective agents (e.g., dexrazoxane to reduce doxorubicin cardiotoxicity, leucovorin to rescue normal cells from methotrexate toxicity). Optimized Dosing and Scheduling: Adjusting the dose, frequency, and duration of chemotherapy administration can allow normal cells to recover between treatment cycles, thereby reducing cumulative toxicity. This includes dose-dense regimens or metronomic dosing. Combination Therapy: Using multiple anticancer drugs with different mechanisms of action and non-overlapping toxicities allows for lower doses of each individual drug. This reduces the specific toxicity associated with high doses of a single agent while maintaining or improving overall efficacy. Prodrugs and Drug Delivery Systems: Prodrugs: These are inactive compounds that are converted into their active, cytotoxic form preferentially within cancer cells or at the tumor site, minimizing systemic exposure to the active drug. Example:* Capecitabine is a prodrug converted to 5-fluorouracil primarily in tumor cells. Drug Delivery Systems: Encapsulating anticancer drugs in liposomes or nanoparticles can alter their pharmacokinetics, allowing for preferential accumulation in tumor tissue and reduced exposure to healthy tissues, thereby decreasing systemic toxicity. Example:* Liposomal doxorubicin. 2. Classify antifungal drugs according to their mode of action and give relevant examples of drugs for each class. Antifungal drugs are classified based on how they target specific components or processes essential for fungal cell survival. Drugs Affecting Fungal Cell Membrane (Ergosterol Synthesis/Function): Polyenes: These drugs bind directly to ergosterol, a sterol unique to fungal cell membranes, forming pores that disrupt membrane integrity and lead to leakage of intracellular contents. Examples:* Amphotericin B, Nystatin. Azoles (Imidazoles and Triazoles): These drugs inhibit 14--demethylase, an enzyme crucial for ergosterol synthesis. This leads to the accumulation of toxic sterol precursors and impaired membrane function. Examples:* Fluconazole, Itraconazole, Voriconazole, Ketoconazole, Clotrimazole. Allylamines: These drugs inhibit squalene epoxidase, another enzyme in the ergosterol synthesis pathway. This results in squalene accumulation (toxic) and ergosterol deficiency. Examples:* Terbinafine, Naftifine. Drugs Affecting Fungal Cell Wall Synthesis: Echinocandins: These drugs inhibit -(1,3)-D-glucan synthase, an enzyme essential for the synthesis of -(1,3)-D-glucan, a major structural component of the fungal cell wall. This weakens the cell wall, leading to osmotic lysis. Examples:* Caspofungin, Micafungin, Anidulafungin. Drugs Affecting Fungal Nucleic Acid Synthesis: Flucytosine (5-FC): This is a prodrug that is converted to 5-fluorouracil (5-FU) inside fungal cells by cytosine deaminase. 5-FU then interferes with fungal DNA and RNA synthesis, disrupting cell division and protein production. Example:* Flucytosine. Drugs Affecting Fungal Mitosis (Microtubule Function): Griseofulvin: This drug interferes with microtubule assembly and function within fungal cells, disrupting mitotic spindle formation and inhibiting fungal cell division. It also binds to keratin, preventing new infections. Example:* Griseofulvin. Last free one today — make it count tomorrow, or type /upgrade for unlimited.