1. Introduction to Clinical Pharmacology Chapter 11 Antiviral Drugs

2. Antivirals: Actions Combat viral infections
Interfere with the virus’s ability to reproduce in a cell
Can be toxic to human cells
Are more difficult to develop

3. Antivirals: Uses
Labeled uses: CMV in transplant patients; HSV-1 and -2 (genital) and herpes zoster; HIV; influenza A and B; RSV; hepatitis B and C
Unlabeled uses: CMV and HSV infections after transplantation procedures and varicella pneumonia

4. Antivirals: Adverse Reactions
Gastrointestinal reactions
Nausea; vomiting; diarrhea
Other reactions
Headache; rash; fever; insomnia

5. Antivirals: Contraindications and Precautions
Contraindicated in patients with a history of allergies
Cidofovir (Vistide) contraindicated for patients with renal impairment and with medications that are nephrotoxic, such as aminoglycosides
Ribavirin contraindicated for patients with unstable cardiac disease

6. Antivirals: Contraindications and Precautions (cont.)
Use during pregnancy and lactation only when the benefit outweighs the risk to the fetus or child
Used cautiously in patients with:
Renal impairment; low blood cell counts; history of epilepsy; history of respiratory disease

7. Antivirals: Interactions
Probenecid: > serum levels of the antivirals
Cimetidine: > serum levels of antiviral valacyclovir
Ibuprofen: > serum level of antiviral devoir
Imipenem/cilastatin: with ganciclovir only— increased risk of seizures
Anticholinergic agents: with amantadine only— increase adverse reactions of anticholinergic agent
Theophylline: with acyclovir only, increased serum level of theophylline

8. Antiretrovirals: Actions
Retroviruses: highly active antiretroviral therapy (HAART)
Protease inhibitors and reverse transcriptase inhibitors
Nonnucleoside reverse transcriptase inhibitors
Early inhibitors
Integrase inhibitors

9. Antiretrovirals: Uses and Adverse Reactions
Used in the treatment of HBV, HIV and AIDS
Adverse reactions:
Gastrointestinal reactions: nausea; vomiting; diarrhea; altered taste
Other reactions: headache; fever; chills; rash; numbness and tingling in the circumoral area (around the mouth) or peripherally or both

10. Antiretrovirals: Contraindications and Precautions
Contraindicated in patients:
With a history of allergies to the drug; during lactation
Who are taking cisapride, pimozide, triazolam, midazolam, or an ergot derivative
Used cautiously in patients:
With diabetes mellitus; impaired hepatic function; pregnancy; hemophilia

11. Antiretrovirals: Interactions
Antifungals: increased serum level of the antiretroviral
Clarithromycin: increased serum level of both drugs
Sildenafil: increased adverse reactions of sildenafil
Opioid analgesics: risk of toxicity with ritonavir

12. Antiretrovirals: Interactions (cont.)
Anticoagulant, anticonvulsant, antiparasitic agents: decreased effectiveness when taking ritonavir
Interleukins: risk of antiretroviral toxicity
Fentanyl: increased serum level of fentanyl
Oral contraceptives: decreased effectiveness of the birth control agent
Rifampin: with efavirenz, nevirapine only, decreased serum levels of antivirals

13. Nursing Process: Assessment
Preadministration assessment:
Determine the patient’s general state of health and resistance to infection
Record vital signs, symptoms, and complaints
Additional assessments may be necessary in certain types of viral infections

14. Nursing Process: Assessment (cont.)
Ongoing assessment:
Monitor for and report any adverse reactions from the antiviral drug
Inspect the IV site several times a day for redness, inflammation, or pain and report any signs of phlebitis

15. Nursing Process: Nursing Diagnosis
Risk for Imbalanced Nutrition: Less Than Body Requirements
Risk for Impaired Skin Integrity
Risk for Injury
Body Image Disturbance
Acute Pain

16. Nursing Process: Planning
The expected outcome includes an optimal response to therapy:
Management of adverse drug reactions
Understanding of and compliance with the prescribed treatment regimen

17. Nursing Process: Implementation
Promoting an optimal response therapy:
Allow the patient and family members time to talk and ask questions
Amantadine: observe the patient for adverse effects
Ribavirin: discard and replace the solution in the SPAG-2 aerosol generator every 24 hours; monitor respiratory function closely throughout therapy; is a pregnancy category X drug

18. Nursing Process: Implementation (cont.)
Monitoring and managing patient needs:
Nutritional imbalance
Help reduce effects of nausea; keep the atmosphere clean and free of odors; provide good oral care before and after meals; notify if nausea is severe

19. Nursing Process: Implementation (cont.)
Monitoring and managing patient needs (cont.)
Impaired skin integrity
Monitor any skin lesions carefully for worsening or improvement; notify
If administering by the IV route: closely observe the injection site for signs of phlebitis; monitor vital signs

20. Nursing Process: Implementation (cont.)
Monitoring and managing patient needs (cont.)
Risk for injury
Monitor acutely ill patients carefully; place call lights in a convenient place for the patient; plan activities so as to provide adequate rest periods; watch for signs of peripheral neuropathy

21. Nursing Process: Implementation (cont.)
Monitoring and managing patient needs (cont.)
Body image disturbance
Spend time with patients, encouraging them to verbalize their feelings regarding any change in appearance

22. Nursing Process: Implementation (cont.)
Monitoring and managing patient needs (cont.)
Acute pain
Assess patients for pain when performing routine vital signs check; explore any pain for location and intensity
Herbal Alert: St. John’s wort

23. Nursing Process: Implementation (cont.)
Educating the patient and family
Explain the dosage regimen and advise to take the drug as prescribed only
Educate the patient of potential adverse reactions, and explain the necessity of contacting the primary health care provider immediately if symptoms for adverse reactions occur
Develop an appropriate teaching plan

24. Nursing Process: Evaluation
The therapeutic effect is achieved; symptoms of the disease process subside or diminish
Adverse reactions are identified, reported, and managed
Patient and family demonstrate understanding of the drug regimen
Patient verbalizes the importance of complying with the prescribed therapeutic regimen

25. Question Is the following statement true or false?
A virus is larger than a bacterium.

26. Answer
False
A virus is smaller than a bacterium. To reproduce, the virus needs cellular material of another living cell. Viral infections range from the common cold to chronic systemic infections of the liver or immune system.

27. Question Is the following statement true or false?
In most situations, antivirals have major adverse reactions.

28. Answer
False
In most situations, antivirals have minor adverse reactions such as gastrointestinal disturbances or flu-like symptoms.

29. Question Is the following statement true or false?
Antiretroviral drugs are used primarily to reduce viral load in patients with HIV.

30. Answer
True
Antiretroviral drugs are used primarily to reduce viral load in patients with HIV. Multiple drugs are used to attack the virus at different parts of the life cycle; this is termed highly active antiretroviral therapy (HAART).