ANTIVIRAL AND ANTITUBERCULAR AGENTS

ANTIVIRAL AGENTS
WHAT IS A VIRUS?virus.jpg
  • VERY SMALL MICROORGANISMS (much smaller than bacteria)
  • CAN ONLY REPRODUCE INSIDE THE CELL OF A HOST (human, animal, plant, bacteria, protozoans)
  • VIRION (mature virus)
  • Immunocompromised patients have frequent viral infections (Cancer patients, Transplant patients, AIDS patient)

PARTS OF A VIRUS
  • GENOME (inner core-RNA and DNA stored)
  • CAPSID (protein coat that protects the genome)
  • ENVELOPE (outermost layer-not present in all viruses)

VIRAL REPLICATION
  1. Virus attaches to host cell
  2. Uncoationg of virus and entry of viral nucleic acid into host cell nucleus
  3. The virus takes control of DNA, RNA, and/or protein productions
  4. Production of viral subunits
  5. Assemble of virions
  6. Release of virions



CURRENT VIRUSES CONTROLLED BY ANTIVIRAL THERAPY
Remember: Medications do not kill the virus they only reduce the duration of symptoms!
  • Cytomegalovirus(CMV)virus_2.jpg
  • Hepatitis viruses
  • Herpes viruses (HSV)
  • Human immunodeficiency virus (HIV)
  • Influenza viruses (the "flu")
  • respiratory syncytial virus (RSV)

ANTIVIRAL MEDICATIONS
  • Antiviral agents (Nonretroviral)-- used to treat viruses other than HIV
  • Antiretroviral agents-- used to treat infections caused by HIV



ANTIVIRAL AGENTS
A. Ganciclovir(DHPG)-
  • used to treat CMV retinitis and systemic
  • mechanism of action: inhibits viral replication
  • Administrated by mouth or intravenously (IV)
  • Side effects- Nausea, Vomiting, Anorexia
  • Adverse effects-Bone marrow toxicity
B. Acyclovir-
  • used to treat HSV-1, HSV-2, VZV (which include Herpes, Chicken pox, and Shingles)
  • mechanism of action: Inhibits viral replication
  • Administrated by mouth or IV
  • Side effects- Burning when applied topically, Nausea, Vomiting, Diarrhea, Headache
  • Adverse effects- Seizures, Acute Renal failure
C. Foscarnet (Foscavir)
  • used to treat CMV in immunodeficient clients
  • used to treat HSV in clients resistant to acyclovir
  • Administrated IV only
  • Side effects- Headache, Nausea, Vomiting, Diarrhea
  • Adverse effects- Seizures Acute renal failure
D. Ribavirin-
  • used to treat RSV in hospitalized infant
  • Administered by inhalation
  • Side Effects- Nausea, Vomiting, Tachycardia




sneezing.jpgINFLUENZA "THE FLU" You-Tube Video: How flu Viruses Attack National Geographic
DRUGS TO TREAT THE FLU--
a. oseltamivir (Tamiful)

  • Treats influenza A&B
  • Can be used if symptomatic 2 days or less
  • Administrated by oral route
  • Side effects- Nausea and Vomiting

b. zanamivir (Relenza)
  • Treat influenza A&B
  • Can be used if symptomatic 2 days or less
  • Administrated by inhalation
  • Side effects- Nausea, Diarrhea, Sinusitis



Human Immunodeficiency Virus (HIV)
  • Retrovirus
  • Transmitted by: sexual activity, intravenous drug use, perinatally from mother to child
  • Detected by ELISA (enzyme-linked immunosorbent assay)- based on presence of human antibodies to the virus in the blood
  • Four stages
    • Stage one: Asymptomatic Infection-first few weeks after exposure; will have swollen lymph node; will test HIV negative still
    • Stage two: Early, General symptoms of the disease-week 3 to 3 months after exposure; continued swollen lymph nodes, flu-like symptoms; will test HIV positive
    • Stage three: Moderate symptoms- continued diarrhea, weight loss, opportunistic infections start (toxoplasmosis of the brain, Candiadiasis of the lungs, esophagus, trachea, PCP, CMV disease, HSV infections, Kaposi's sarcoma)
    • Stage four:Severe Symptoms: often lead to death; formally called the Full Blown AIDS stage
  • You-Tube Video: HIV Virus


Antiretroviral Agents:hiv_cell.ashx.gif
A. HAART

  • Highly active antiretroviral therapy
  • Includes at least three medications that work in different ways to reduce the viral load
  • Goal is to keep viral load less than 50 copies/ml
B. Zidovudine (AZT)

  • used to treat HIV, AIDS, ARC
  • Mechanism of Action: Nucleoside Reverse Transcriptase Inhibitor (NRTI)
  • Administered by mouth on an empty stomach (needs a gastric pH of 2 to work) or IV
  • Side effects- Nausea, headache, hair loss
  • Adverse effects- Bone Marrow suppression
  • Safe in pregnancy, breastfeeding, and for use in infants
C. Didanosine (ddl)

  • used to treat HIV, AIDS, ARC
  • Mechanism of Action: NRTI
  • Administered by mouth
  • Side effects- Nausea, Vomiting, Diarrhea
  • Adverse effects- Pancreatitis, Peripheral neuropathy, Seizures,
D. Nevirapine (Viramune)

  • used to treat HIV, AIDS,
  • Mechanism of Action: Nonnucleoside Reverse Transcriptase Inhibitors
  • Administered by mouth
  • Adverse effects- Fever, Rash, Nausea, Headache, Abnormal liver function tests
E. Tenofovir (Viread)

  • used to treat HIV, AIDS,
  • Mechanism of Action: Nucleotide Reverse Transcriptase Inhibitors
  • Administered by mouth
  • Reported effects include Lactic acidosis, Severe hepatomegaly
F. Indinavir (Crixavan)

  • used to treat HIV, AIDS, ARC
  • Mechanism of Action: Protease Inhibitors (PI)
  • Administered by mouth on an empty stomach (needs a pH of 2 to work)
  • Side effects- Nausea, Vomiting, Diarrhea, Headache, Anorexia
G. Enfuvirtide (Fuzeon)

  • used to treat HIV, AIDS, ARC
  • Mechanism of Action: inhibits viral fusion
  • Administered by subcutaneous injection
  • Side effects- Anxiety, taste disturbance, anorexia, constipation
  • Adverse effects- Renal failure


ANTITUBERCULAR AGENTS

IMPORTANT INFORMATION TO KNOW BEFORE WE START.....tuberculosis.jpg

  • TUBERCULOSIS (TB)
  • Caused by Mycobacterium tuberculosis
  • Antitubercular agents treat all forms of Mycobacterium
  • Common infection sites: Lungs(primary site), Brain, Bone, Liver, Kidney

MYCOBACTERIUM INFECTIONS SPREAD BY:

  • droplets, coughing, sneezing and gain entry by inhalation
  • spread to other body organs via blood and lymphatic system
  • may become dormant or walled off by calcified or fibrous tissue

Antitubercular Drugs:
Name of Drug
Mechanism of Action
Route of Administration
Side Effects
Adverse Effects
Special Considerations
Isoniazid (INH)
Cell wall synthesis inhibitor
by mouth (PO), Intramuscular
Peripheral neuropathy (supplement with B6)
Seizures,
Hepatotoxicity
-Metabolized by acetelation
-Can be taken with meals for GI upset
-No alcohol
-Increased blood sugar levels in diabetics
-Oral contraceptives lose effectiveness
Streptomycin
Protein wall synthesis inhibitor
Intramuscular
Tremors, muscle twitching
Headaches
Seizures
Ototoxicity
-No alcohol
Rifampin
Protein wall synthesis inhibitor
PO, IV
Headache
Red-orange-brown discoloration: urine
feces, saliva, tears, skin, sputum
Hepatotoxicity
-No alcohol
-Oral contraceptives lose effectiveness
Ethambutol
Other
PO
Optic neuritis
Blindness
-No alcohol
Pyrazinamide (PZA)
Other
PO
Headache
Hepatotoxicity
-No alcohol

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Reference: Lilley, L., Harrington, S., & Snyder, J. (2011). Pharmacology and the nursing process. (6th ed.).
St. Louis: Mosby