Cytotoxic Agents Overview

Overview of Cytotoxic Agents

• Cytotoxic agents, also known as cytotoxic drugs or chemotherapeutic agents, are toxic to living cells.
• They are commonly used in cancer treatment to inhibit the growth and division of rapidly dividing cells, including cancer cells.
• These drugs target both cancerous and normal cells that have a high rate of proliferation.
• The primary mode of action involves disrupting the cell cycle or interfering with DNA synthesis, leading to cell death.
• Common side effects include bone marrow suppression leading to anemia, increased susceptibility to infections, gastrointestinal issues, and hair loss.

Examples of Cytotoxic Drugs

• Methotrexate
• Cyclophosphamide
• Doxorubicin
• Vinblastine
• Paclitaxel

Methotrexate

• Mode of Action: Inhibits dihydrofolate reductase, disrupting DNA synthesis and cell division.
• Dosage: Varies based on the type and stage of cancer
• Route of Administration: Can be given orally, intravenously, or intramuscularly.
• Recommended dose varies from 10 to 5000 mg/m2 IV.
• Lower doses such as 20 to 30 mg/m2/week IM can be given.
• A tablet dose of 20 mg/m2 orally once weekly can be used as a maintenance chemotherapy regimen
• Side Effects: Bone marrow suppression, mucositis, hepatotoxicity, renal dysfunction.
• Nursing Responsibility: Monitor renal and hepatic function, administer folic acid to mitigate side effects, and educate on signs of toxicity.

Cyclophosphamide

• Mode of Action: Alkylating agent interfering with DNA replication by forming cross-links.
• Dosage: Adjusted based on the type of cancer and patient factors; often administered in cycles.
• Route of Administration: Primarily administered intravenously.
• When used alone, the initial dose for patients with no hematologic deficiency is 40 to 50 mg/kg IV in divided doses over 2 to 5 days
• Alternative dose: 10 to 15 mg/kg IV every 7 to 10 days OR 3 to 5 mg/kg IV 2 times a week
• Oral dose: 1 to 5 mg/kg/day (initial and maintenance dosing).
• Side Effects: Myelosuppression, hemorrhagic cystitis, nausea, alopecia.
• Nursing Responsibility: Encourage adequate fluid intake to prevent cystitis, monitor for signs of infection, administer mesne to protect against bladder toxicity.

Doxorubicin

• Mode of Action: Intercalates with DNA and inhibits topoisomerase, preventing DNA replication.
• Dosage: Based on the type of cancer, administered intravenously every 3 weeks in many regimens.
• Route of Administration: Intravenous administration.
• As a single agent: 60 to 75 mg/m2 IV over 3 to 10 minutes every 21 days
• In combination with other chemotherapy drugs: 40 to 75 mg/m2 IV every 21 to 28 days
• Side Effects: Cardiotoxicity, myelosuppression, nausea, alopecia.
• Nursing Responsibility: Monitor cardiac function, administer dexrazoxane to reduce cardiotoxicity, manage nausea, and monitor for signs of infection.

Vinblastine

• Mode of Action: Inhibits microtubule formation, disrupting mitosis.
• Dosage: Administered intravenously; dose may vary based on cancer type.
• The manufacturer outlines the following conservative incremental approach to dosage, given every 7 days for adults:
• First dose: 3.7 mg/m2 IV
• Second dose: 5.5 mg/m2 IV
• Third dose: 7.4 mg/m2 IV
• Fourth dose: 9.25 mg/m2 IV
• Fifth dose: 11.1 mg/m2 IV
• For most adult patients, the weekly dose will be 5.5 to 7.4 mg/m2 IV.
• Route of Administration: Typically administered intravenously.
• Side Effects: Myelosuppression, peripheral neuropathy, constipation.
• Nursing Responsibility: Monitor blood counts, manage neuropathy symptoms, and encourage adequate fluid and fiber intake.

Paclitaxel

• Mode of Action: Stabilizes microtubules, preventing cell division.
• Dosage: Administered intravenously over 3 hours; dose and frequency depend on cancer type.
• Route of Administration: Primarily intravenous.
• 135 mg/m2 IV over 3 hours every 3 weeks
• OR 175 mg/m2 IV over 3 hours every 3 weeks
• Side Effects: Peripheral neuropathy, myelosuppression, hypersensitivity reactions.
• Nursing Responsibility: Pre-medicate for hypersensitivity reactions, monitor for neuropathy, manage side effects, assess for signs of infection.

Antihistamines Overview

• Antihistamines counteract the effects of histamine, a substance produced by the body as part of an allergic reaction.
• Histamine is released in response to allergens, causing itching, sneezing, runny nose, and watery eyes.
• Antihistamines work by blocking histamine receptors which then alleviate these symptoms.

Types of Antihistamines

• First-Generation Antihistamines:
• Examples include diphenhydramine, chlorpheniramine, and promethazine.
• They often cause drowsiness and are used for allergies, motion sickness, and sleep aid.
• Typically shorter-acting and may need to be taken multiple times a day.
• Second-Generation Antihistamines:
• Examples include loratadine, cetirizine, and fexofenadine.
• They generally cause less drowsiness compared to first-generation antihistamines.
• They are longer-acting, usually taken once a day.
• Common indications for the use of antihistamines include allergic rhinitis (hay fever), hives (urticaria), allergic conjunctivitis, and certain allergic skin reactions. They may also be used for symptoms related to insect bites or stings.
• Antihistamines are available in various forms, including oral tablets, capsules, liquid formulations, and, in some cases, as nasal sprays or eye drops.

Diphenhydramine

• Blocks histamine receptors, preventing histamine-mediated allergic responses.
• Typically taken every 4 to 6 hours; dosage varies based on formulation (e.g., 25-50 mg).
• Available in oral tablets, capsules, and liquid formulations.
• Side effects include drowsiness, dry mouth, blurred vision, and constipation.
• Caution patients about drowsiness, monitor for dry mouth, advise against alcohol use.

Loratadine

• Blocks histamine receptors without causing significant sedation.
• Typically taken once daily (e.g., 10 mg) for allergy relief.
• Available in oral tablets or liquid.
• Side effects are generally well-tolerated; minimal sedation, headache, dry mouth.
• Educate on once-daily dosing, monitor for adverse effects, provide information on potential drug interactions.

Cetirizine

• Selectively inhibits histamine receptors, minimizing sedative effects.
• Typically taken once daily (e.g., 10 mg) for allergy relief.
• Usually administered orally, available as tablets or syrup.
• Side effects include mild drowsiness, dry mouth, and headache.
• Monitor for sedation, educate on once-daily dosing, assess for interactions.

Fexofenadine

• Selectively blocks histamine receptors without significant sedation.
• Usually taken once daily (e.g., 180 mg) for allergy relief.
• Oral tablets or liquid.
• Side effects are generally well-tolerated; minimal drowsiness, headache, and nausea.
• Educate on once-daily dosing, monitor for adverse effects, assess for drug interactions.

Clemastine

• Antagonizes histamine receptors, alleviating allergy symptoms.
• Typically taken 1.34 mg every 12 hours; dosage may vary.
• Oral tablets.
• Side effects include Sedation, dry mouth, blurred vision.
• Monitor for sedation, advise on proper dosing, assess for contraindications.

Vitamins Overview:

• Vitamin drugs are pharmaceutical formulations of essential vitamins, administered to address deficiencies or supplement dietary intake.
• Vitamins are organic compounds necessary for various biochemical processes, crucial for maintaining good health.
• Vitamin drugs are available in different forms: tablets, capsules, liquid solutions, or injectables. The formulations are designed to provide concentrated doses of specific vitamins to ensure adequate intake.

Vitamin D

• Facilitates calcium absorption in the intestines, essential for bone health.
• Dosage varies based on deficiency; commonly prescribed in international units (IU).
• Route of Administration: Often oral, can be in the form of tablets, capsules, or liquid.
• Side effects are rare at recommended doses, but excessive intake may lead to hypercalcemia.
• Nursing Responsibility: Monitor calcium levels, educate on proper administration, assess for signs of overdose.

Vitamin C

• Antioxidant, aids in collagen synthesis, and enhances iron absorption.
• Route of Administration: Typically oral, available as tablets or in liquid form.
• Generally well-tolerated, but high doses may cause gastrointestinal upset.
• Nursing Responsibility: Monitor for signs of scurvy improvement, educate on dietary sources, assess for gastrointestinal issues.

Vitamin B12

• Essential for DNA synthesis and neurological function.
• Dosage: Varies, often administered in micrograms, especially for deficiency.
• Route of Administration: Intramuscular or subcutaneous injection, occasionally oral.
• Side Effects: Generally well-tolerated; rare hypersensitivity reactions.
• Nursing Responsibility: Administer via appropriate injection technique, monitor for improvement in symptoms, educate on dietary sources.

Vitamin K

• Essential for blood clotting and bone metabolism.
• Dosage: Varies; commonly administered in micrograms.
• Route of Administration: Usually oral or injection.
• Side Effects: Rare at recommended doses; high doses may cause hemolysis.
• Nursing Responsibility: Monitor coagulation parameters, administer as prescribed for anticoagulant reversal, educate on dietary sources.

Vitamin A

• Essential for vision, immune function, and skin health.
• Dosage: Varies; often in international units (IU).
• Route of Administration: Typically oral, available in various forms.
• Side Effects: Excessive intake can lead to toxicity with symptoms like nausea, dizziness, and skin changes.

Minerals Overview

• Mineral drugs, or mineral supplements, are pharmaceutical formulations containing specific minerals essential for various physiological functions.
• Supplements address mineral deficiencies or provide support when dietary intake is insufficient.
• Minerals are inorganic elements that play crucial roles in processes such as bone formation, nerve function, fluid balance, and energy production.
• Mineral supplements are available in various forms, including tablets, capsules, powders, and liquid formulations.
• The dosage and form of administration depend on the specific mineral and the individual's health needs.

Iron

• Essential for hemoglobin synthesis, oxygen transport, and cellular function.
• Dosage: Varies based on the severity of iron deficiency, often in milligrams.
• Route of Administration: Usually oral; available as tablets or liquid.
• Side Effects: Gastrointestinal upset, constipation; in high doses, toxicity can occur.
• Nursing Responsibility: Administer with vitamin C to enhance absorption, monitor for gastrointestinal issues, educate on dietary sources.

Calcium

• Integral for bone and teeth formation, blood clotting, and nerve function.
• Dosage: Varies; often in milligrams; adjustments based on dietary intake and deficiencies.
• Route of Administration: Oral; available in various forms, including tablets and chewable.
• Side Effects: Constipation, gas, may interfere with the absorption of other minerals.
• Nursing Responsibility: Administer with meals for better absorption, monitor for signs of hypercalcemia, educate on dietary sources.

Magnesium

• Supports muscle and nerve function, energy production, and bone health.
• Dosage: Varies; often in milligrams; adjustments based on deficiencies.
• Route of Administration: Oral; available as tablets or capsules.
• Side Effects: Diarrhea, nausea; excessive intake can lead to hypermagnesemia.

Zinc

• Essential for immune function, wound healing, and DNA synthesis.
• Dosage: Varies; often in milligrams; adjustments based on deficiencies.
• Route of Administration: Oral; available as tablets or syrup.
• Side Effects: Gastrointestinal upset, metallic taste; excessive intake can lead to toxicity.

Potassium

• Crucial for heart function, muscle contraction, and fluid balance.
• Dosage: Varies; often in milliequivalents (mEq); adjustments based on deficiencies.
• Route of Administration: Oral; available as tablets or liquid; intravenous in severe cases.
• Side Effects: Gastrointestinal upset, hyperkalemia if excessive intake.

Overview of Psychotropic Drugs:

• Psychotropic drugs, also known as psychoactive drugs, affect mental processes, mood, and behavior by acting on the central nervous system.
• Common for managing mental health conditions and disorders.

Selective Serotonin Reuptake Inhibitors (SSRIs)

• Increases serotonin levels by inhibiting reuptake, improving mood.
• Route of Administration: Oral; available as tablets or capsules.
• Side Effects: Nausea, insomnia, sexual dysfunction.
• Nursing Responsibility: Monitor for side effects, assess for suicidal ideation, educate on consistent dosing.

Benzodiazepines

• Enhances the effect of GABA, a neurotransmitter that inhibits brain activity.
• Route of Administration: Oral, intravenous (IV).
• Side Effects: Sedation, dizziness, risk of dependence.
• Nursing Responsibility: Monitor for sedation, educate on short-term use, assess for signs of dependence.

Antipsychotics

• Blocks dopamine receptors, reducing psychotic symptoms.
• Route of Administration: Oral, intramuscular (IM).
• Side Effects: Weight gain, sedation, metabolic effects.

Mood Stabilizers

• Alters sodium transport in nerve and muscle cells, stabilizing mood.
• Route of Administration: Oral.
• Side Effects: Tremor, polyuria, potential for toxicity.
• Nursing Responsibility: Monitor serum lithium levels, assess renal function, educate on adequate fluid intake.

Tricyclic Antidepressants (TCAs)

• Blocks reuptake of norepinephrine and serotonin, elevating mood.
• Route of Administration: Oral.
• Side Effects: Dry mouth, blurred vision, constipation.
• Nursing Responsibility: Monitor for anticholinergic effects, assess for suicidal ideation, educate on side effects.