ATI 2026 Immune System Pharmacology Master Review Notes

Master Overview of the Immune System Unit

The Immune System Unit is organized into 44 primary categories which represent the core focus of the curriculum:

  • Vaccines & Immunity
  • Cancer Medications
  • Immunosuppressants
  • HIV Medications

Part 1: Immunity and Vaccines

Active vs. Passive Immunity

This is a critical concept frequently tested on the ATI exam.

Active Immunity

Active immunity occurs when the body actively produces its own antibodies. It is characterized by long-term protection.

  • Natural Active Immunity: Occurs when a person is exposed to a live pathogen and develops the disease.
    • Example: A chickenpox infection.
    • Result: The body develops antibodies, often leading to lifelong immunity.
  • Artificial Active Immunity: Occurs when a person receives a vaccine that triggers an immune response without causing the illness.
    • Examples: MMR (Measles, Mumps, Rubella), Hepatitis B, Tetanus toxoid.
    • Result: Antibodies are produced, providing long-lasting protection.
  • Memory Trick: ACTIVE = Antibodies Actually produced by the person.
Passive Immunity

Passive immunity involves the transfer of pre-made antibodies to an individual. It provides immediate but temporary protection.

  • Natural Passive Immunity: Passed from mother to baby.
    • Examples: Antibodies transferred via the placenta or through breast milk.
  • Artificial Passive Immunity: Direct administration of antibodies.
    • Examples: Antitoxins and Immunoglobulins.
  • Memory Trick: PASSIVE = Premade antibodies.
ATI High-Yield Comparison
  • Immediate effect: Passive immunity works immediately.
  • Longevity: Active immunity lasts longer.

Vaccine Classifications

Live Vaccines

These contain organisms that have been weakened (attenuated) but are still alive.

  • Examples: MMR, Varicella, Intranasal Flu vaccine.
  • Contraindications:
    • Pregnancy
    • Immunocompromised individuals
    • Transplant patients
Inactivated Vaccines

These vaccines contain killed (dead) organisms. They are generally considered safer than live vaccines.

  • Examples: Injectable Flu vaccine, IPV (Inactivated Poliovirus Vaccine), Hepatitis A.
Toxoid Vaccines

These contain inactivated toxins produced by bacteria.

  • Examples: Tetanus, Diphtheria.
  • Note: ATI emphasizes that Tetanus is a Toxoid Vaccine.

Vaccine Schedules

Age Birth to 66 Years

Key vaccines to know for this age group:

  • Hepatitis B
  • Rotavirus
  • DTaP (Diphtheria, Tetanus, and Acellular Pertussis)
  • Hib (Haemophilus influenzae type b)
  • IPV (Inactivated Poliovirus Vaccine)
  • PCV (Pneumococcal Conjugate Vaccine)
  • MMR (Measles, Mumps, Rubella)
  • Varicella
  • Flu
  • COVID-1919
Age 11−1211-12 Years

Key vaccines for this age group:

  • Tdap booster
  • HPV (Human Papillomavirus)
  • MenACWY (Meningococcal conjugate)
Age 1616 Years

Key vaccines for this age group:

  • MenACWY Booster
  • MenB (Meningococcal B)
Adult Vaccine Schedule
  • Yearly: Influenza vaccine.
  • Every 1010 Years: Td or Tdap booster.
  • Age 50+50+: Shingles vaccine.
  • Age 65+65+: Pneumococcal vaccine.
  • Older Adults: RSV (Respiratory Syncytial Virus) vaccine.

Part 2: Immunosuppressants

Immunosuppressants are utilized for conditions such as organ transplantation, Rheumatoid Arthritis (RA), Psoriasis, and Lupus.

Cyclosporine

This is a high-priority medication for ATI.

  • Major Adverse Effect: Nephrotoxicity (kidney damage).
  • Monitoring Required: BUN (Blood Urea Nitrogen) and Creatinine levels.
  • Other Side Effects: Hypertension, tremors, and gingival hyperplasia (overgrowth of gum tissue).
  • Patient Teaching:
    • Avoid grapefruit juice.
    • Avoid live vaccines.

Tacrolimus

Another critical medication for nurse monitoring.

  • Major Adverse Effects: Nephrotoxicity, Neurotoxicity, and Hyperglycemia.
  • Monitoring Required: Kidney function and blood glucose levels.

Azathioprine

  • Major Problem: Bone marrow suppression.
  • Monitoring Required: CBC (Complete Blood Count) and Liver enzymes.

Mycophenolate

  • Major Issues: Elevated risk of infection and Leukopenia.
  • Monitoring Required: CBC.
  • Safety Warning: Teratogenic (do not use during pregnancy).

Monoclonal Antibodies

Most medications in this class end with the suffix "-mab."

Adalimumab (Humira)
  • Indications: Rheumatoid Arthritis (RA), Crohn's disease, Psoriasis.
  • Critical Nursing Action: TB (Tuberculosis) screening is mandatory BEFORE treatment begins.
  • Patient Monitoring: Watch for symptoms of infection such as fever, cough, and night sweats.
Infliximab
  • Primary concern: Reactivation of tuberculosis.
  • Clinical Requirement: TB testing is required.
Rituximab
  • Major Problem: Infusion reactions.
  • Symptoms: Fever, chills, and hypotension.
  • Nursing Action: Slow or stop the infusion if a reaction occurs.

Corticosteroids (Prednisone)

  • Long-term Side Effects: Hyperglycemia, Osteoporosis, Weight gain, Infection, and Hypertension.
  • Patient Teaching:
    • Take the medication with food.
    • Never stop the medication abruptly (must be tapered).

Part 3: Cancer Medications

General Principles of Chemotherapy

Cancer drugs target and kill cancer cells, but they also destroy healthy, rapidly dividing cells (such as those in the skin, hair, GI tract, and bone marrow). This non-selective action causes most side effects.

Bone Marrow Suppression

This is the most important concept in cancer pharmacology for ATI testing. Nurses must monitor for:

  • Low WBC (Leukopenia): Leads to infection.
  • Low RBC (Anemia): Leads to fatigue and weakness.
  • Low Platelets (Thrombocytopenia): Leads to bleeding.
  • Priority Action: Monitor the CBC (Complete Blood Count).

Antimetabolites: Methotrexate

  • Clinical Uses: Leukemia, Lymphoma, Choriocarcinoma, Rheumatoid Arthritis (RA), and Psoriasis.
  • Major Adverse Effects:
    • Bone marrow suppression.
    • Oral ulcerations (stomatitis).
    • GI ulcerations.
    • Hepatotoxicity (liver damage).
    • Pulmonary fibrosis.
  • Monitoring Required: CBC, Hgb/Hct, and LFTs (Liver Function Tests).
  • Antidote: LEUCOVORIN (Highly tested concept).
  • Contraindications: Pregnancy and Alcohol consumption.
  • Patient Teaching (Report immediately): Fever, sore throat, mouth ulcers, blood in stool, jaundice, and shortness of breath.

Taxanes: Paclitaxel

  • Clinical Uses: Breast cancer, ovarian cancer, and lung cancer.
  • Mechanism of Action: Stops mitosis during the G22/M phase.
  • ATI Key Phrase: Prevents cell division.

Topoisomerase Inhibitors: Topotecan

  • Clinical Uses: Ovarian cancer and small-cell lung cancer.
  • Mechanism of Action: Prevents DNA recoiling.
  • Result: DNA breaks occur, leading to cell death.

Hormonal Cancer Medications

Leuprolide
  • Drug Class: GnRH Agonist.
  • Clinical Use: Advanced prostate cancer.
  • Expected Physiological Response:
    • Initially: Increase in testosterone.
    • Subsequently: Decrease in testosterone.
  • Note: A temporary worsening of symptoms can occur at the start of therapy.
Flutamide
  • Drug Class: Antiandrogen.
  • Usage: Often used in conjunction with Leuprolide.
  • Purpose: Blocks the effects of testosterone.
  • ATI Focus: Prevents problems caused by the initial testosterone surge from Leuprolide.
Tamoxifen
  • Clinical Use: Estrogen-positive breast cancer.
  • Side Effects to Monitor: DVT (Deep Vein Thrombosis), PE (Pulmonary Embolism), and Endometrial cancer.
  • Patient Teaching (Report immediately): Leg swelling, leg pain, chest pain, and abnormal vaginal bleeding.

Part 4: HIV Medications

HIV Foundations

  • Target: HIV specifically attacks CD4 T-helper cells.
  • Progression: If left untreated, HIV progresses to AIDS (Acquired Immunodeficiency Syndrome).
  • Goals of Therapy:
    1. Lower the viral load.
    2. Raise the CD4 count.
    3. Prevent progression to AIDS.
    4. Prevent drug resistance.

Laboratory Interpretation

  • Good Outcomes: High CD4 count and Low Viral Load.
  • Bad Outcomes: Low CD4 count and High Viral Load.

The Golden HIV Rule

Never use one medication alone. Always use combination therapy to prevent drug resistance.

Medication Classes

Viral Entry Blockers

These prevent the virus from entering the host cell.

  • Enfuvirtide (Fusion Inhibitor):
    • Mechanism: Prevents HIV from fusing with the CD4 cell membrane.
    • Memory Trick: Blocks the front door.
  • Maraviroc (CCR5 Antagonist):
    • Specific Condition: Works only on CCR5-Tropic HIV.
    • Mechanism: Blocks the CCR5 receptor.
    • Side Effects: Dizziness, sleep disturbances, paresthesia, liver damage, respiratory infections, and allergic reactions.
NRTIs (Nucleoside Reverse Transcriptase Inhibitors)
  • Prototype: Zidovudine.
  • Uses: Treatment of HIV and prevention of maternal-fetal transmission.
  • Mechanism: Stops viral DNA synthesis.
  • Nursing Point: Medication must be taken exactly as prescribed for efficacy.
NNRTIs (Non-nucleoside Reverse Transcriptase Inhibitors)
  • Prototype: Efavirenz.
  • Mechanism: Directly inhibits reverse transcriptase.
  • Specific Action: Works against HIV-11.
  • Note: HIV-11 is not the same as HIV-22; medications often target specific strains.
Integrase Inhibitors
  • Prototype: Raltegravir.
  • Usage: HIV-11 that is resistant to other therapies.
  • Mechanism: Blocks the integration of viral DNA into host DNA.
Protease Inhibitors
  • Prototype: Ritonavir.
  • Other Examples: Atazanavir, Darunavir, Saquinavir.
  • Mechanism: Blocks viral maturation.
  • Result: The virus remains immature and noninfectious.
  • Memory Trick: Protease inhibitors stop HIV from "growing up."

Auxiliary Medications and Priority Scenarios

Filgrastim

  • Purpose: Increases neutrophil production.
  • Indication: Chemotherapy-induced neutropenia.
  • Major Side Effect: Bone pain.

ATI Priority Questions

  • Who to See First?: A transplant patient presenting with a fever (risk of rejection or life-threatening infection).
  • When to Hold Medication?: Hold Methotrexate if the patient has severe neutropenia (low WBC).
  • When to Call the Provider?: A patient on Tamoxifen complaining of unilateral calf pain (sign of DVT).
  • Most Important Lab?: CBC during chemotherapy to monitor for bone marrow suppression.
  • Highest Priority Teaching?: Emphasize that HIV medications must be taken exactly as prescribed to prevent resistance.

20 Facts for Final Review

  1. Active immunity involves the body making its own antibodies.
  2. Passive immunity involves the person receiving pre-made antibodies.
  3. Live vaccines are contraindicated in immunocompromised clients.
  4. MMR is a live vaccine.
  5. Varicella is a live vaccine.
  6. Cyclosporine causes nephrotoxicity.
  7. Tacrolimus causes nephrotoxicity and hyperglycemia.
  8. Adalimumab requires TB screening prior to use.
  9. Infliximab requires TB screening prior to use.
  10. Rituximab can cause severe infusion reactions.
  11. Prednisone should not be stopped abruptly due to the risk of adrenal crisis.
  12. Bone marrow suppression is the primary complication of chemotherapy.
  13. The antidote for Methotrexate toxicity is Leucovorin.
  14. Methotrexate commonly causes mouth ulcers (stomatitis).
  15. Tamoxifen can cause DVT and endometrial cancer.
  16. Leuprolide initially causes an increase in testosterone levels.
  17. Flutamide blocks the effects of testosterone.
  18. HIV targets and destroys CD4 T cells.
  19. Desired HIV lab results are a High CD4 count and a Low Viral Load.
  20. HIV medications are almost always administered in combination to prevent drug resistance.