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

1. Antifungal Agents
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2. Antifungal Agents
• Drugs used to treat infections caused by fungi
• Systemic and topical
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3. Cellular Structure of Fungi
• Similar to human cells
• Different steroid present in plasma membranes
• Human: cholesterol
• Fungi: ergosterol
What is the pharmacologic implication of this difference?
Discuss the limitations of antifungal therapy.
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4. Fungi
• Also known as mycoses
• Very large and diverse group of microbes
• Broken down into yeast and molds
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5. Yeast
• Single-cell fungi
• Reproduce by budding
• Very useful organisms
– Baking
– Alcoholic beverages
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6. Molds
• Mulitcellular
• Characterized by long, branching filaments
called hyphae
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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
• Due to antibiotic therapy, antineoplastics or
immunosuppressants
• May result in overgrowth and systemic
infections
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9. Mycotic Infections
In the mouth:
• Oral candidiasis or thrush
• Newborn infants & immunocompromised pts
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10. Vaginal candidiasis:
• Yeast infection
• Pregnancy, DM, OC
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11. Antifungal Agents
SYSTEMIC
• Examples:
– Amphotericin B
– Fluconazole
– Ketoconazole
– Itraconazole
TOPICAL
• Examples:
– Clotrimazole
– Miconazole
– Nystatin
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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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13. 13

14. Generalized fungal cell depicting the sites of action of the common antifungal
agents.
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15. Antifungal Agents:
Mechanism of Action
Polyenes: amphotericin B and nystatin
• Binds to sterols in cell membrane lining
• Allow K+ & Mg++ to leak out, altering fungal cell
metabolism
• Result: fungal cell death
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16. Antifungal Agents:
Mechanism of Action
Flucytosine
• Also known as 5-fluorocytosine (antimetabolite)
• Taken up by fungal cells and interferes with DNA
synthesis
• Result: fungal cell death
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17. Antifungal Agents:
Mechanism of Action
Imidazoles:
Ketoconazole, miconazole, clotrimazole, fluconazole
• Inhibit an enzyme, resulting in cell membrane leaking
• Lead to altered cell membrane
• Result: fungal cell death
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18. Antifungal Agents:
Mechanism of Action
Griseofulvin
• Disrupt cell division
• Result: inhibit fungal mitosis (reproduction)
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19. Antifungal Agents: Side Effects
Amphotericin B
Fever chills headache
Anorexia malaise nausea
hypotension tachycardia
muscle and joint pain
Lowered K+ and Mg++ levels
*renal toxicity
*neurotoxicity: seizure & paresthesia
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20. Antifungal Agents: Side Effects
Fluconazole
• N&V, diarrhea, abd’l pain
• Increased liver function studies
Flucytosine
• N&V, anorexia
Griseofulvin
• Rash, urticaria, headache, N&V, anorexia
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21. Antifungal Agents:
Nursing Implications
• Before beginning therapy, assess for hypersensitivity,
possible contraindications, and conditions that require
cautious use.
• Obtain baseline VS,CBC, liver function studies and
ECG
• Assess for other medications used (prescribed and
OTC) in order to avoid drug interactions.
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22. Antifungal Agents:
Nursing Implications
• Follow manufacturer’s directions carefully for
reconstitution and administration.
• Monitor VS of pt receiving IV infusions every 15-30
mins
• 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
• To reduce the severity of infusion-related reactions, pretreatment
with an antipyretic (acetaminophen), antihistamines and antiemetics
may be given.
• A test dose of 1mg per 20 mL of 5% dextrose in water infused over
30 minutes should be given.
• Use IV infusion and the most distal veins possible.
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24. Antifungal Agents:
Nursing Implications
• Tissue extravasation of fluconazole at the IV site may lead to
tissue necrosis – monitor IV site carefully.
• Oral forms of griseofulvin should be given with meals to
decrease GI upset.
• Monitor carefully for side/adverse effects.
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25. Antifungal Agents:
Nursing Implications
Monitor for therapeutic effects:
• Easing of the symptoms of infection
• Improved energy levels
• Normal vital signs, including temperature
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26. Antiviral Agents
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27. Understanding Viruses
Viral Replication
• A virus cannot replicate on its own.
• It must attach to and enter a host cell.
• It then uses the host cell’s 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.
• Any drug that kills a virus may also kill our
cells.
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29. Viral Infections
Competent immune system:
• Best response to viral infections
• A well-functioning immune system will eliminate or effectively destroy
virus replication
Immunocompromised patients have frequent viral infections
• Cancer pts, esp leukemia/lymphoma
• Transplant pts, due to pharmacological therapy
• AIDS pts, disease attacks immune system
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30. Antiviral Drugs
Key characteristics:
• Able to enter the cells infected with virus
• Interfere with viral nucleic acid synthesis and/or regulation.
• Some agents interfere with ability of virus to bind to cells.
• Some agents stimulate the body’s immune system.
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31. Antiviral Drugs
Viruses killed by current antiviral therapy:
• Cytomegalovirus (CMV)
• Herpes simplex virus (HSV)
• Human immunodeficiency virus (HIV)
• Influenza A (flu)
• Respiratory syncytial virus (RSV)
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32. Antivirals: Mechanism of Action
• Inhibit viral replication
• Inhibit viral attachment
• Prevent genetic copying of virus
• Prevent viral protein production
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33. Antivirals Synthetic Purine Nucleoside
Analogues
2 types of nucleosides:
Purine nucleosides
• Guanine
• Adenosine
Pyrimidine nucleosides
• Thymine
• cytosine
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34. Antivirals: Purine Nucleosides
Agent Antiviral Activity
Guanines
HSV 1&2
1.acyclovir
CMV retinitis & systemic infection
2.ganciclovir Influenza type A&B, RSV
3.ribavirin
Adenosines HIV
HSV, herpes zoster
1.didanosine
2.vidarabine 34

35. Antivirals:Pyrimidine Nucleosides
Agent Antiviral Activity
Cytosine
1. lamivudine HIV
2. zalcitabine HIV
Thymine
1. Idoxuridine HSV
2. Stavudine HIV
3. Trifluridine HSV
4. Zidovudine HIV
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36. Other Antiviral Drugs
1. Amantadine (Symmetrel)
2. Rimantadine (Flumadine)
– Influenza A
3. Foscarnet (Foscavir)
– CMV (retinitis & systemic)
4. Neuraminidase Inhibitors: oseltamivir (Tamiflu)
– Influenza A&B
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37. Antivirals: Side Effects
Acyclovir
• Burning when topically applied, N&V, diarrhea, headache
Amantadine & rimantadine
• Anticholinergic effects, insomnia, lightheadedness,
anorexia, nausea
Didanosine
• Pancreatitis, peripheral neuropathies, seizures
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38. Antivirals: Side Effects
Zidovudine (AZT)
– Bone marrow suppression, nausea, headache
Foscarnet (Foscavir)
– HA, seizures, acute renal failure, N&V, diarrhea
Ganciclovir (Cytovene)
– Bone marrow toxicity, N&V, anorexia
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39. Antivirals: Nursing Implications
• Before beginning therapy, thoroughly assess underlying
disease and medical hx, including allergies.
• Assess baseline VS and nutritional status
• Assess for contraindications, conditions that may indicate
cautious use, and potential drug interactions.
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40. Antivirals: Nursing Implications
• Teach proper application technique for ointment, aerosol
powders, etc
• Emphasize handwashing before and after administration of
medications to prevent site contamination and spread of
infection.
• Patient should wear glove when applying ointments or
solutions to affected areas.
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41. Antivirals: Nursing Implications
• Instruct to consult their physician before taking any
other medication, including OTC medications
• Emphasize the importance of good hygiene.
• Inform patient that antiviral agents are not cures, but do
help to manage symptoms.
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42. Antivirals: Nursing Implications
• Instruct on the importance of taking these medications
exactly as prescribed and for the full course of tx
• With zidovudine:
– Inform pt that HAIR LOSS MAY occur so they are
prepared for this rare AE.
– Should be taken on an empty stomach.
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43. Antivirals: Nursing Implications
• Monitor for side effects:
– Effects are varied and specific to each agent
• Monitor for therapeutic effects:
– Vary depending on the type of viral infection
– 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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44. Antimalarial
Antiprotozoal
Antihelmintic Agents
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45. Protozoal Infections
Parasitic protozoa: live in or on humans
• Malaria
• Leishmaniasis
• Amebiasis
• Giardiasis
• Trichomoniasis
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46. Malaria
• Caused by plasmodium protozoa
• 4 different species
• Causes:
– Bite of infected adult mosquito
– blood transfusion,
– Congenitally
– infected needles by drug abusers
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47. Malarial Parasite
2 Interdependent Life Cycles
• Sexual cycle: in mosquito
• Asexual cycle: in human
– Knowledge of the life cycle is essential in understanding
antimalarial drug tx
– Drugs are only effective during asexual cycle.
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48. Plasmodium Life Cycle
Asexual cycle: 2 phases
• Exoerythrocytic phase Occurs “outside” the RBC
• Erythrocytic phase Occurs “inside” the RBC
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49. Antimalarial Agents
Attack the parasite during asexual phase when it is vulnerable
• Erythrocytic phase drugs:
– chloroquinine
– hydroxychloroquine
– quinine
– mefloquine
• Exoerythrocytic phase drugs:
– 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
• Bind to parasite nucleoproteins and interfere with protein synthesis
• Prevent vital parasite-sustaining substances from being formed
• Alter pH within the parasite
• Interfere with parasite’s ability to metabolize and use erythrocyte
hemoglobin
• Effective only during the erythrocytic phase
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51. Antimalarials:
Mechanism of Action
4-aminoquinoline derivatives quinine and mefloquine
• Alter pH within the parasite
• Interfere with parasite’s ability to metabolize and use
erythrocyte hemoglobin
• Effective only during erythrocytic phase.
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52. Antimalarials:
Mechanism of Action
Diaminophyrimidines pyrimethamine and trimethoprim
• Inhibit dihydrofolate reductase in parasite
• This enzyme is needed by parasite to make essential substances
• 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
• Only exoerythrocytic drug
• Binds and alter DNA
sulfonamides,tetracycline, clindamycin
– Used in combination with antimalarials to increase
protozoacidal effects
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54. Antimalarials: Drug Effects
• Kills parasitic organisms
• Chloroquine and hydroxychloroquine also
have antiinflammatory effects.
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55. Antimalarials: Therapeutic Uses
• Used to kill plasmodium organisms
• Drugs have varying effectiveness on different malaria
organisms
• Some agents are used for prophylaxis against malaria
• Chloroquine is also used for rheumatois arthritis and
lupus.
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56. Antimalarials: Side Effects
• Primarily GI:
– N&V
– Diarrhea
– Anorexia
– Abd’l pain
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57. Antiprotozoals
• atovaquone(Mepron)
• metronidazole (Flagyl)
• pentamidine (Pentam)
• iodoquinol (Yodoxin, Di-Quinol)
• paromomycin (Humatin)
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58. Protozoal Infections
• Amebiasis
• Giardiasis
• Pneumocystosis
• Toxoplasmosis
• Trichomoniasis
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59. Protozoal Infections
Transmission
• Person-to-person
• Ingestion of contaminated water/food
• Direct contact with parasite
• Insect bite (mosquito/tick)
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60. Antiprotozoals: Mechanism of Action
atovaquone (Mepron)
• Protozoal energy comes from the mitochondria
• Atovaquone: selective inhibition of mitochondrial electron transport
• 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
• Disruption of DNA synthesis as well as nucleic
acid synthesis
• Bactericidal, amebicidal, trichomonocidal
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62. Antiprotozoals: Mechanism of Action
Pentamidine
• Inhibit DNA & RNA
• Binds to and aggregate ribosomes
• Directly lethal to P. carinii
• Inhibit:
– glucose metabolism
– CHON & RNA synthesis
– intracellular amino acid transport
Mainly used to tx P. carinii
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63. Antiprotozoals: Mechanism of Action
Iodoquinol
• “luminal” or “contact” amedicide
• Acts primarily in the intestinal lumen of the infected
host
• Directly kills protozoa
Used to tx intestinal amebiasis
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64. Antiprotozoals: Mechanism of Action
Paromomycin
• “luminal” or “contact” amebicide
• kills by inhibiting protein synthesis
Tx of amebiasis & intestinal protozoal infections
Adjunct therapy in hepatic coma
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65. Antiprotozoals:
Side Effects
Atovaquone
– N&V, diarrhea, anorexia
Metronidazole
– METALLIC TASTE,N&V, diarrhea, abd’l cramps
Iodoquinol
– N&V, diarrhea, anorexia, agranulocytosis
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66. Antiprotozoals:
Side Effects
Pentamidine
– Bronchospasm
– Leukemia
– Thrombocytopenia
– Acute pancreatitis
– ARF
– Inc liver function studies
Paromomycin
– GI s/sx
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67. Antihelmintics
• diethylcarbamazine (Hetrazan)
• mebendazole (Vermox)
• niclosamide (Niclocide)
• oxamniquine (Vansil)
• piperazine (Vermizine)
• praziquantel (Biltricide)
• pyrantel (Antiminth)
thiabendazole (Mintezol)
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68. Antihelmintics
• Drugs used to tx parasitic worm infections:
helmintic infection
• Unlike protozoa, helminths are large and have
complex cellular structures
• Drug tx is very specific
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69. Antihelmintics
• It is VERY IMPORTANT to identify the causative
worm
• Done by finding the parasite ova or larvae in
feces, urine, blood, sputum or tissue
– Cestodes (tapeworms)
– Nematodes (roundworms)
– Trematodes (flukes)
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70. Antihelmintics: Mechanism of Action
diethylcarbamazine (Hetrazan)
– Inhibit rate of embryogenesis
thiabendazole (Mintezol)
– Inhibits helminth-specific enzyme, fumarate reductase
Both used for nematodes
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71. Antihelmintics: Mechanism of Action
piperazine (Vermizine) and pyrantel (Antiminth)
• 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)
• 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)
• Causes the worm to become dislodged from the
GI wall
• 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)
• Cause paralysis of worms’ musculature and immobilization
of their suckers
• 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
– N&V, diarrhea, dizziness, HA
mebendazole
– Diarrhea, abd’l pain, TISSUE NECROSIS
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76. Antimalarial, Antiprotozoal, Antihelmintic Agents:
Nursing Implications
• Before beginning therapy, perform a thorough
health hx & medication hx, and assess for
allergies
• Check baseline VS
• Check for conditions that may contraindicate
use, and for potential drug interactions.
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77. Antimalarial, Antiprotozoal, Antihelmintic Agents:
Nursing Implications
• 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
• Administer ALL agents as ordered and for the prescribed
length of time
• Most agents should be TAKEN WITH FOOD to reduce GI
upset.
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78. Antimalarial, Antiprotozoal, Antihelmintic Agents:
Nursing Implications
• Assess for + of malarial sx
• When used for prophylaxis, agents should be started 2
WEEKS BEFORE potential exposure to malaria, and
for 8 WEEKS AFTER leaving the area.
• Medications are taken weekly, with 8 ounces of water.
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79. Antimalarial, Antiprotozoal, Antihelmintic Agents:
Nursing Implications
• Instruct to notify HCP immediately id ringing in
the ears, hearing decreases, visual difficulties,
N&V, profuse diarrhea, or abd’l pain occur.
• 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:
• Ensure pt knows the SE that should be reported.
• Monitor for therapeutic effects and AE with long-
term therapy.
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