Immunologic System Medications - Chapter 17

• Chapter 17 covers Immunologic System Medications

Learning Outcomes

• Key term definitions.
• Five classifications of anti-infectives
• Natural and acquired immunity and how they occur
• Three different types of antineoplastic medications
• Toxic effects of antineoplastic medications

Vocabulary

• Active artificial immunity is immunity gained through vaccination
• Active natural immunity refers to immunity gained through exposure to an antigen
• Anaerobe is an organism that grows without air
• Aerobe is an organism that grows with air
• Antibodies are a blood protein produced in response to and counteracting a specific antigen
• Antigen is a toxin or other foreign substance that induces an immune response in the body, especially the production of antibodies
• Autoimmune is relating to disease caused by antibodies or lymphocytes produced against substances naturally present in the body
• Bactericidal is a substance that kills bacteria
• Bacteriostatic is a substance that inhibits bacterial growth
• Benign refers to a growth that is not cancerous
• Chemotherapy refers to the treatment of disease by chemical agents
• Culture and sensitivity (C&S) is a test to identify the bacteria and suitable antibiotic to treat it
• Host is an animal or plant on or in which a parasite or commensal organism lives
• Inflammation is a localized physical condition in which part of the body becomes reddened, swollen, hot, and often painful, especially as a reaction to injury or infection
• Malignant refers to cancerous growth that can spread
• Metastasis refers to the development of secondary malignant growths at a distance from a primary site of cancer
• Nosocomial refers to hospital acquired infections
• Passive artificial immunity is acquired through the transfer of antibodies formed by another individual or animal
• Passive natural immunity is acquired from antibody transfer from mother
• Pathogenic is a bacterium, virus, or other microorganism that can cause disease
• Superinfection occurs when on top of an existing inflection a new inflection manifests

The Immune Response

• An antigen invades the body triggering the body's attack
• Inflammation limits spread of microbes
• First phase of immune response sees the:
  • Release of Bradykinin
  • Complement
  • Histamine and leukotrienes
  • Prostaglandins
• Second phase of immune response:
  • Launches attack through body by secreting antibodies
  • B cells (memory cells) record attack to guard against future attack
  • T cells (CD cells) create cytokines

Medications That Affect the Immune System

• Anti-inflammatory
• Anti-infective
• Antitoxin
• Antifungal
• Antiviral
• Antiparasitic
• Vaccines
• Antineoplastic (chemotherapy)

Anti-Inflammatory Medications

• Stop or reduce the inflammatory response with use in patients with autoimmune disorders
• The immune system attacks itself and must be stopped to halt damage
• Examples:
  • Rheumatoid arthritis
  • Dermatitis
  • Multiple sclerosis
  • Systemic lupus erythematosus

Immunosuppressants

• Used for long-term therapy of inflammatory diseases
• Rheumatoid arthritis: azathioprine (Imuran, Azasan), cyclosporine (Neoral, Sandimmune, and Gengraf)
• Psoriasis: cyclosporine, sirolimus (Rapamune)
• Crohn's disease: azathioprine (Imuran, Azasan)

Anti-Infective Medications

• Classified by mechanisms of action or chemical structure
• These target the processes of the pathogenic (disease-causing) microorganism, such as:
  • Protein synthesis
  • Inhibiting DNA or RNA synthesis
  • Destroying the cell wall

Antibiotics

• Treat bacterial infections and bacteria are potentially vulnerable to antibiotics
• Bacteria are named based on:
  • Their shape (rods, spheres, spirals)
  • Staining (gram-negative or gram-positive)
  • Their need for oxygen (aerobe or anaerobe)
• A broad-spectrum antibiotic is effective against many types of bacteria, for e.g., vancomycin, gentamicin
• Antibiotics kill healthy/normal flora which can result in super-infections
• Yeast infections can also occur during antibiotic use
• Culture and sensitivity tests (C&S) are performed to identify bacteria and suitable antibiotics
• May result in an initial prescription being changed to an antibiotic more suitable for the causative organism

Penicillins

• One of oldest antibiotics (since World War 2); available in oral, topical, injection for common infections like strep throat, otitis media
• Kills gram-positive and gram-negative bacteria by destroying cell walls
• The least expensive option, but many patients are allergic to penicillins
• For example: ampicillin (Omnipen), amoxicillin (Amoxil), penicillin (Pen VK)

Cephalosporins

• Similar to penicillins but are more expensive
• Composed of four generations (based on their activity); first generation are used for patients allergic to penicillin:
  • Gram-positive bacteria, cefazolin (Ancef, Kefzol), cefaroxil (Duricef)
• Second generation:
  • Treats nosocomial pneumonia and pelvic or intra-abdominal infections
  • Cefprozil (Cefzil), Cefuroxine (Zinacef)
• Third Generation:
  • Gram-negative bacteria
  • Ceftriaxone (Rocephin)
• Fourth generation is used intravenously only for severe nosocomial surgical infections
  • Cefepime (Maxipime)
• These are used to treat and prevent infections
• Alcohol use can cause abdominal side effect

Tetracyclines

• Bacteria becoming resistant to this class
• These prevent protein synthesis, thus interrupting reproduction of bacteria
• Effective against many gram-negative and gram-positive microbes
• Should NOT be used in children or pregnant women as can cause permanent staining in teeth of child or fetus
• For, e.g., Doxycycline (Vibramycin), minocycline (Solodyn), tetracycline (Sumycin)

Macrolides

• Inhibit reproduction microorganisms by inhibiting protein synthesis
• These may be either bactericidal or bacteriostatic
• These are used to treat many different infections; for, e.g., Erythromycin (EES Granules), clarithromycin (Biaxin), azithromycin (Zithromax)

Aminoglycosides

• More toxic than other antibiotics: blood needs to be monitored and are used only when no other suitable anti-infective is available
• These are Nephro-toxic and ototoxic
• Effective against aerobic gram-negative bacteria
• These are administered topically via ointments, eye drops, and ear drops or as an IV injection
• For e.g., amikacin (Amikin), gentamicin (Garamycin), tobramycin (Nebcin)

Quinolone Medications

• Bacteriostatic and prevent bacteria from growing
• Reserved for antibiotic-resistant strains of bacteria because of rare, severe side effects
• Administered via IV, ophthalmic, or oral and are useful for chronic urinary tract infections
• For, e.g., Ciprofloxacin (Cipro), ofloxacin (Floxin)

Sulfonamides

• One of earliest classes of antibiotics used to kill bacteria by interrupting their metabolism
• Collect in bladder prior to excretion; so, very effective treating urinary tract infections
• Many allergies to sulfonamides
• Examples:
  • Trimethoprim-sulfamethoxazole (Septra, Bactrim)
  • Erythromycin-sulfisoxazole (Pediazole)

Antituberculosis Agents

• Antibiotics to treat Mycobacterium tuberculosis
• Mixture of two to four medications simultaneously daily for up to 1 year
• Cycloserine (Seromycin) prevents bacteria from growing in the body
• Rifampin (Rifadin) treats or prevents TB and turns body secretions red/brown

Antitoxins

• Antibodies created to counteract toxin in person at high risk for disease or condition
• For e.g., patient exposed to diphtheria, tetanus, or botulism but immunity adequate to meet threat
• Tetanus immune globulin (Baytet) provides immediate neutralization of tetanus toxoid

Antifungal Medications

• Used to treat:
  • Tinea pedis (athlete's foot)
  • Candidiasis (yeast infection)
• Available as topical medications like:
  • Ketoconazole (Extina, Nizoral)
  • Miconazole (Desenex, Micatin)
  • Nystatin (Mycostatin)
• And systemic, but systemic fungal infections are more likely to occur in people who are immunocompromised, for e.g.:
  • Fluconazole (Diflucan)
  • Itraconazole (Sporanox)
  • Ketoconazole (Nizoral)
  • Fungizone (Amphotericin B), reserved for life-threatening fungal infections due to serious side effects

Viruses

• Viruses require a host such as:
  • Humans
  • Plants
  • Animals
• Smaller than other microorganisms
• Insert genetic material into host, i.e. cytomegalovirus, rabies, smallpox, chickenpox, shingles, influenza, common cold, herpes

Antiviral Medications

• Antiviral therapy inhibits reproduction of a virus but most medications shorten duration of symptoms only and do not prevent illness
• Valacyclovir (Valtrex) treats viruses that causes herpes, chickenpox, and shingles
• Zanamivir (Relenza) and oseltamivir (Tamiflu) treat influenza type A and B

Human Immunodeficiency Virus (HIV)

• An understanding of the replication cycle of HIV is needed to understand how it works
• After the virus enters the body, it attaches to CD4 receptors on T4 (helper) lymphocytes, it un-coats and puts its genetic material into the host T4 cell
• This genetic material forms DNA that is passed to other T4 lymphocytes with the help of a viral enzyme called protease
• After a latent phase, HIV may produce as many as 10 billion virions every day
• Current guidelines recommend that antiretroviral therapy is initiated in all HIV-infected patients to reduce the risk of disease progression

Antiretroviral Medications

• Group of medications to treat retroviruses like HIV
• Retroviruses imbed genetic material in gene of healthy cells and are difficult to fight
• Medications are classified according to where in reproduction process they act
• Nucleoside reverse transcriptase inhibitors (NRTIs)-Lamivudine
• Fusion Inhibitor -Enfuvirtide
• Protease inhibitors (PIs)- Ritonavir
• HIV integrase strand transfer inhibitors- Elvitegravir
• CCR5 coreceptor antagonist- Maraviroc

Antimalarials

• Prevent and treat malaria by inhibiting the growth of the malaria parasite in the red blood cells of the body
• For, e.g.,:
  • Atovaquone/proguanil (Malarone)
  • Chloroquine (Aralen)
  • Mefloquine (Lariam)
  • Primaquine

Cancer

• Disorderly and uncontrolled division of cells, usually more rapid than healthy cells
• Nicotine and alcohol can trigger this cell division to begin
• The body is unable to identify an abnormal cell
• Metastasis involves the spread of cancerous cells to surrounding or distant body parts

Chemotherapy

• Combination of several antineoplastic and cytotoxic medications which are delivered intramuscularly (IM), intravenously (IV), subcutaneously (SC), or intrathecally (fluid around spine and brain) Creams and gels may be used to treat mild forms of skin cancer
• Each individual receives a combination of medications depending upon their specific cancer

Adverse Affects of Chemotherapy

• Common side effects:
  • Nausea, vomiting
  • Alopecia
  • Decreased blood counts
• Caustic to tissue:
  • Common to insert central lines
  • Dangerous to those administering medication
  • Only those allowed by law may handle/administer
• Toxic effects:
  • Organ damage

Immunomodulators

• Stimulate immune system in patients with multiple myeloma
• Examples:
  • Filgristim
  • Lenalidomide (Revlimid)
  • Thalidomide (Thalomid)
    • Has a High risk of birth defects
    • Multiple birth control methods required

Chapter 17 covers immunologic system medications. Key topics include key term definitions, classifications of anti-infectives, natural and acquired immunity, types of antineoplastic medications, and their toxic effects. Important vocabulary includes the definitions of active artificial immunity, active natural immunity, and other key concepts.