This document discusses antifungal, antiviral, antimalarial, and antiprotozoal agents. It provides information on:
1) The types of infections each class of agents treats, such as fungal infections, viral infections like HIV and influenza, malaria caused by plasmodium parasites, and protozoal infections including amebiasis and pneumocystis.
2) The mechanisms of action of these agents, such as how polyenes like amphotericin B work by binding to sterols in fungal cell membranes, and how nucleoside analogues like acyclovir inhibit viral DNA synthesis.
3) Important aspects of administering these agents, like monitoring for side
3. Cellular Structure of Fungi
โข Similar to human cells
โข Different steroid present in plasma membranes
โข Human: cholesterol
โข Fungi: ergosterol
What is the pharmacologic implication of this difference?
Discuss the limitations of antifungal therapy.
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4. Fungi
โข Also known as mycoses
โข Very large and diverse group of microbes
โข Broken down into yeast and molds
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7. Mycotic Infections
Four General Types:
1. Cutaneous
2. Subcutaneous
3. Superficial
4. Systemic
* can be life-threatening
* usually occur in immunocompromised host
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8. Mycotic Infections
Candida albicans
โข Due to antibiotic therapy, antineoplastics or
immunosuppressants
โข May result in overgrowth and systemic
infections
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9. Mycotic Infections
In the mouth:
โข Oral candidiasis or thrush
โข Newborn infants & immunocompromised pts
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12. Antifungal Agents
Broken down into 4 groups based on their
chemical structure
1. Polyenes: amphotericin B & nystatin
2. Flucytosine
3. Imidazole:
ketoconazole, miconazole, clotrimazol
e, fluconazole
4. Griseofulvin
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15. Antifungal Agents:
Mechanism of Action
Polyenes: amphotericin B and nystatin
โข Binds to sterols in cell membrane lining
โข Allow K+ & Mg++ to leak out, altering fungal cell
metabolism
โข Result: fungal cell death
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16. Antifungal Agents:
Mechanism of Action
Flucytosine
โข Also known as 5-fluorocytosine (antimetabolite)
โข Taken up by fungal cells and interferes with DNA
synthesis
โข Result: fungal cell death
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17. Antifungal Agents:
Mechanism of Action
Imidazoles:
Ketoconazole, miconazole, clotrimazole, fluconazole
โข Inhibit an enzyme, resulting in cell membrane leaking
โข Lead to altered cell membrane
โข Result: fungal cell death
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21. Antifungal Agents:
Nursing Implications
โข Before beginning therapy, assess for hypersensitivity,
possible contraindications, and conditions that require
cautious use.
โข Obtain baseline VS,CBC, liver function studies and
ECG
โข Assess for other medications used (prescribed and
OTC) in order to avoid drug interactions.
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22. Antifungal Agents:
Nursing Implications
โข Follow manufacturerโs directions carefully for
reconstitution and administration.
โข Monitor VS of pt receiving IV infusions every 15-30
mins
โข During IV infusions, monitor I&O and urinalysis
findings to identify adverse renal effects.
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23. Antifungal Agents:
Nursing Implications
Amphotericin B
โข To reduce the severity of infusion-related reactions, pretreatment
with an antipyretic (acetaminophen), antihistamines and antiemetics
may be given.
โข A test dose of 1mg per 20 mL of 5% dextrose in water infused over
30 minutes should be given.
โข Use IV infusion and the most distal veins possible.
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24. Antifungal Agents:
Nursing Implications
โข Tissue extravasation of fluconazole at the IV site may lead to
tissue necrosis โ monitor IV site carefully.
โข Oral forms of griseofulvin should be given with meals to
decrease GI upset.
โข Monitor carefully for side/adverse effects.
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25. Antifungal Agents:
Nursing Implications
Monitor for therapeutic effects:
โข Easing of the symptoms of infection
โข Improved energy levels
โข Normal vital signs, including temperature
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27. Understanding Viruses
Viral Replication
โข A virus cannot replicate on its own.
โข It must attach to and enter a host cell.
โข It then uses the host cellโs energy to synthesize protein,
DNA and RNA.
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28. Understanding Viruses
Viruses are difficult to kill because they live
inside our cells.
โข Any drug that kills a virus may also kill our
cells.
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29. Viral Infections
Competent immune system:
โข Best response to viral infections
โข A well-functioning immune system will eliminate or effectively destroy
virus replication
Immunocompromised patients have frequent viral infections
โข Cancer pts, esp leukemia/lymphoma
โข Transplant pts, due to pharmacological therapy
โข AIDS pts, disease attacks immune system
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30. Antiviral Drugs
Key characteristics:
โข Able to enter the cells infected with virus
โข Interfere with viral nucleic acid synthesis and/or regulation.
โข Some agents interfere with ability of virus to bind to cells.
โข Some agents stimulate the bodyโs immune system.
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31. Antiviral Drugs
Viruses killed by current antiviral therapy:
โข Cytomegalovirus (CMV)
โข Herpes simplex virus (HSV)
โข Human immunodeficiency virus (HIV)
โข Influenza A (flu)
โข Respiratory syncytial virus (RSV)
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32. Antivirals: Mechanism of Action
โข Inhibit viral replication
โข Inhibit viral attachment
โข Prevent genetic copying of virus
โข Prevent viral protein production
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38. Antivirals: Side Effects
Zidovudine (AZT)
โ Bone marrow suppression, nausea, headache
Foscarnet (Foscavir)
โ HA, seizures, acute renal failure, N&V, diarrhea
Ganciclovir (Cytovene)
โ Bone marrow toxicity, N&V, anorexia
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39. Antivirals: Nursing Implications
โข Before beginning therapy, thoroughly assess underlying
disease and medical hx, including allergies.
โข Assess baseline VS and nutritional status
โข Assess for contraindications, conditions that may indicate
cautious use, and potential drug interactions.
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40. Antivirals: Nursing Implications
โข Teach proper application technique for ointment, aerosol
powders, etc
โข Emphasize handwashing before and after administration of
medications to prevent site contamination and spread of
infection.
โข Patient should wear glove when applying ointments or
solutions to affected areas.
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41. Antivirals: Nursing Implications
โข Instruct to consult their physician before taking any
other medication, including OTC medications
โข Emphasize the importance of good hygiene.
โข Inform patient that antiviral agents are not cures, but do
help to manage symptoms.
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42. Antivirals: Nursing Implications
โข Instruct on the importance of taking these medications
exactly as prescribed and for the full course of tx
โข With zidovudine:
โ Inform pt that HAIR LOSS MAY occur so they are
prepared for this rare AE.
โ Should be taken on an empty stomach.
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43. Antivirals: Nursing Implications
โข Monitor for side effects:
โ Effects are varied and specific to each agent
โข Monitor for therapeutic effects:
โ Vary depending on the type of viral infection
โ Effect range from delayed progression of AIDS and ARC(AIDS-
related complex) to decrease in flu-like symptomes, decrease
frequency of herpes-like flare-ups or crusting over of herpetic
lesions
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46. Malaria
โข Caused by plasmodium protozoa
โข 4 different species
โข Causes:
โ Bite of infected adult mosquito
โ blood transfusion,
โ Congenitally
โ infected needles by drug abusers
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47. Malarial Parasite
2 Interdependent Life Cycles
โข Sexual cycle: in mosquito
โข Asexual cycle: in human
โ Knowledge of the life cycle is essential in understanding
antimalarial drug tx
โ Drugs are only effective during asexual cycle.
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48. Plasmodium Life Cycle
Asexual cycle: 2 phases
โข Exoerythrocytic phase Occurs โoutsideโ the RBC
โข Erythrocytic phase Occurs โinsideโ the RBC
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49. Antimalarial Agents
Attack the parasite during asexual phase when it is vulnerable
โข Erythrocytic phase drugs:
โ chloroquinine
โ hydroxychloroquine
โ quinine
โ mefloquine
โข Exoerythrocytic phase drugs:
โ primaquine
May be used together for synergistic or additive killing power.
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50. Antimalarials:
Mechanism of Action
4-aminoquinoline derivatives chloroquine and hydroxychloroquine
โข Bind to parasite nucleoproteins and interfere with protein synthesis
โข Prevent vital parasite-sustaining substances from being formed
โข Alter pH within the parasite
โข Interfere with parasiteโs ability to metabolize and use erythrocyte
hemoglobin
โข Effective only during the erythrocytic phase
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51. Antimalarials:
Mechanism of Action
4-aminoquinoline derivatives quinine and mefloquine
โข Alter pH within the parasite
โข Interfere with parasiteโs ability to metabolize and use
erythrocyte hemoglobin
โข Effective only during erythrocytic phase.
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52. Antimalarials:
Mechanism of Action
Diaminophyrimidines pyrimethamine and trimethoprim
โข Inhibit dihydrofolate reductase in parasite
โข This enzyme is needed by parasite to make essential substances
โข Also blocks synthesis of tetrahydrofolate.
These agents may be used with sulfadoxine or dapsone for synergistic effects.
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53. Antimalarials:
Mechanism of Action
primaquine
โข Only exoerythrocytic drug
โข Binds and alter DNA
sulfonamides,tetracycline, clindamycin
โ Used in combination with antimalarials to increase
protozoacidal effects
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54. Antimalarials: Drug Effects
โข Kills parasitic organisms
โข Chloroquine and hydroxychloroquine also
have antiinflammatory effects.
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55. Antimalarials: Therapeutic Uses
โข Used to kill plasmodium organisms
โข Drugs have varying effectiveness on different malaria
organisms
โข Some agents are used for prophylaxis against malaria
โข Chloroquine is also used for rheumatois arthritis and
lupus.
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60. Antiprotozoals: Mechanism of Action
atovaquone (Mepron)
โข Protozoal energy comes from the mitochondria
โข Atovaquone: selective inhibition of mitochondrial electron transport
โข Result: no energy, leading to cell death
Used to tx mild to moderate P. carinii
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61. Antiprotozoals: Mechanism of Action
Metronidazole
โข Disruption of DNA synthesis as well as nucleic
acid synthesis
โข Bactericidal, amebicidal, trichomonocidal
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62. Antiprotozoals: Mechanism of Action
Pentamidine
โข Inhibit DNA & RNA
โข Binds to and aggregate ribosomes
โข Directly lethal to P. carinii
โข Inhibit:
โ glucose metabolism
โ CHON & RNA synthesis
โ intracellular amino acid transport
Mainly used to tx P. carinii
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63. Antiprotozoals: Mechanism of Action
Iodoquinol
โข โluminalโ or โcontactโ amedicide
โข Acts primarily in the intestinal lumen of the infected
host
โข Directly kills protozoa
Used to tx intestinal amebiasis
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64. Antiprotozoals: Mechanism of Action
Paromomycin
โข โluminalโ or โcontactโ amebicide
โข kills by inhibiting protein synthesis
Tx of amebiasis & intestinal protozoal infections
Adjunct therapy in hepatic coma
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68. Antihelmintics
โข Drugs used to tx parasitic worm infections:
helmintic infection
โข Unlike protozoa, helminths are large and have
complex cellular structures
โข Drug tx is very specific
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69. Antihelmintics
โข It is VERY IMPORTANT to identify the causative
worm
โข Done by finding the parasite ova or larvae in
feces, urine, blood, sputum or tissue
โ Cestodes (tapeworms)
โ Nematodes (roundworms)
โ Trematodes (flukes)
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70. Antihelmintics: Mechanism of Action
diethylcarbamazine (Hetrazan)
โ Inhibit rate of embryogenesis
thiabendazole (Mintezol)
โ Inhibits helminth-specific enzyme, fumarate reductase
Both used for nematodes
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71. Antihelmintics: Mechanism of Action
piperazine (Vermizine) and pyrantel (Antiminth)
โข Blocks acetylcholine at neuromuscular junction,
resulting in paralysis of worms, which are then
expelled through the GI tract
Used to tx nematodes (giant worms & pinworms)
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72. Antihelmintics: Mechanism of Action
mebendazole (Vermox)
โข Inhibits uptake of glucose and other nutrients,
leading to autolysis and death of parasitic worm
Used to tx cestodes & nematodes
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73. Antihelmintics: Mechanism of Action
niclosamide (Niclocide)
โข Causes the worm to become dislodged from the
GI wall
โข They are then digested in the intestines and
expelled.
Used to tx cestodes
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74. Antihelmintics: Mechanism of Action
oxamniquine (Vansil) and praziquantel (Biltricide)
โข Cause paralysis of wormsโ musculature and immobilization
of their suckers
โข Cause worms to dislodge from mesenteric veins to the liver,
then killed by host tissue reactions
Used to tx trematodes, cestodes
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75. Antihelmintics:
Side Effects
niclosamide, oxamniquine, praziquantel, thiabendaz
ole, piperazine, pyrantel
โ N&V, diarrhea, dizziness, HA
mebendazole
โ Diarrhea, abdโl pain, TISSUE NECROSIS
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76. Antimalarial, Antiprotozoal, Antihelmintic Agents:
Nursing Implications
โข Before beginning therapy, perform a thorough
health hx & medication hx, and assess for
allergies
โข Check baseline VS
โข Check for conditions that may contraindicate
use, and for potential drug interactions.
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77. Antimalarial, Antiprotozoal, Antihelmintic Agents:
Nursing Implications
โข Warn the pt ahead of time on some agents may cause urine
to have an asparagus-like odor, or cause an unusual skin
odor, or a metallic taste
โข Administer ALL agents as ordered and for the prescribed
length of time
โข Most agents should be TAKEN WITH FOOD to reduce GI
upset.
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78. Antimalarial, Antiprotozoal, Antihelmintic Agents:
Nursing Implications
โข Assess for + of malarial sx
โข When used for prophylaxis, agents should be started 2
WEEKS BEFORE potential exposure to malaria, and
for 8 WEEKS AFTER leaving the area.
โข Medications are taken weekly, with 8 ounces of water.
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79. Antimalarial, Antiprotozoal, Antihelmintic Agents:
Nursing Implications
โข Instruct to notify HCP immediately id ringing in
the ears, hearing decreases, visual difficulties,
N&V, profuse diarrhea, or abdโl pain occur.
โข Alert pt to possible recurrence of symptoms of
malaria so they will know to seek immediate tx.
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80. Antimalarial, Antiprotozoal, Antihelmintic Agents:
Nursing Implications
Monitor for side effects:
โข Ensure pt knows the SE that should be reported.
โข Monitor for therapeutic effects and AE with long-
term therapy.
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Editor's Notes
Subcutaneous phycomycosis
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