Antiviral agents

Class(es)

Antiviral.
Clinical use(s)

FDA approved: Herpes zoster (shingles), herpes simplex virus (HSV) infections (including genital herpes), varicella (chickenpox), and recurrent herpes simplex labialis (cold sores).
Off-label/clinical use: Chickenpox pneumonia, Bell's palsy, HSV in immunocompromised patients, and eczema herpeticum.
Mechanism(s) of action

It stops the replication of herpes viral DNA by competitively inhibiting viral DNA polymerase, incorporating into and terminating the growing viral DNA chain, and inactivating the viral DNA polymerase.
Key adverse effects

Malaise, renal failure, and headache.
Key drug/food interactions

Nephrotoxic agents.
Special considerations

Renally adjusted: CrCl < 25 ml/min.

Class(es)

Antiviral.
Clinical use(s)

FDA approved: Influenza virus types A and B (treatment and prophylaxis).
Off-label/clinical use: Avian influenza (treatment and prophylaxis).
Mechanism(s) of action

Inhibits influenza virus neuraminidase, which affects viral particle release.
Key adverse effects

Headache, vomiting, and nausea.
Key drug/food interactions

Warfarin.
Special considerations

Renally adjusted: CrCl < 60 ml/min.

Class(es)

Antiretrovial.
Clinical use(s)

HIV/Aids treatment and pre-exposure prophylaxis.
Mechanism(s) of action

Decreases and controls viral load
Key adverse effects

Many common and severe.
Key drug/food interactions

Tons! Check each drug for specific interactions.
Special considerations

Drug classes used in treatment-naïve patients—4 classes typically used in initial regimens:

- Nucleoside Reverse Transcriptase Inhibitors (NRTIs)
- Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs)
- Protease Inhibitors (PIs)
- Integrase Strand Transfer Inhibitors (INSTIs)

Class(es)

Nucleotide reverse transcriptase inhibitor.
Clinical use(s)

FDA approved: HIV (Hepatitis B).
Mechanism(s) of action

Tenofovir diphosphate competes with the natural substrate deoxyadenosine 5'-triphosphate for incorporation into the DNA strand. After incorporation into viral DNA, tenofovir diphosphate inhibits the activity of HIV-1 reverse transcriptase and HBV polymerase by terminating the DNA chain.
Key adverse effects

TDF: Rash, pruritus, nausea, asthenia, depression.
TAF: Abdominal pain, backache, headache, fatigue.
Serious: Lactic acidosis, hepatomegaly with steatosis.
Key drug/food interactions

NSAIDs.
Special considerations

BBW: Severe acute exacerbations of hepatitis B.
TDF: Renal impairment adjust to CrCl < 50 ml/min.
TAF:
Renal impairment mild to severe: No adjustment.
ESRD: Use not recommended.
Hepatic impairment Child-Pugh A: No adjustment
Child-Pugh B or C: Use not recommended.

Class(es)

Non-nucleoside reverse transcriptase inhibitor.
Clinical use(s)

FDA approved: HIV.
Mechanism(s) of action

Through noncompetitive inhibition of HIV-1 reverse transcriptase.
Key adverse effects

Rash, ALT/AST elevation, cholesterol/triglycerides elevation, diarrhea, nausea, and vomiting.
Key drug/food interactions

St John's Wort, carbamazepine, voriconazole.
Special considerations

Hepatic impairment moderate or severe: Use not recommended.

Class(es)

Protease inhibitor.
Clinical use(s)

FDA approved: HIV.
Mechanism(s) of action

Protease inhibitor that prevents the cleavage of Gag and Gag-Pol polyproteins yielding immature, noninfectious virus.
Key adverse effects

Rash, diarrhea, nausea/vomiting, headache, and Stevens-Johnson Syndrome (SJS).
Key drug/food interactions

Phenobarbital, carbamazepine, colchicine, and many more.
Special considerations

Hepatic impairment severe: Use not recommended.

Class(es)

Protease inhibitor.
Clinical use(s)

FDA approved: HIV.
Mechanism(s) of action

Inhibits both HIV proteases, which leaves these enzymes incapable of processing the gag-pol polyprotein precursor. This leads to the production of noninfectious immature HIV particles.
Key adverse effects

Pruritis, rash, abdominal pain, nausea and vomiting, altered sense of taste, arthralgia, asthenia, dizziness, paresthesia, cough.
Key drug/food interactions

Sildenafil, colchicine, carbamazepine, amiodarone, and many more.
Special considerations

BBW: Co-administration with several classes, such as sedative hypnotics, antiarrhythmics, or ergot alkaloids may result in potentially life-threatening events.
Hepatic impairment Child-Pugh C: Use is not recommended.

Class(es)

Integrase inhibitor.
Clinical use(s)

FDA approved: HIV.
Mechanism(s) of action

Integrase strand transfer inhibitor that blocks retroviral DNA integration in the HIV replication cycle.
Key adverse effects

Hyperglycemia, increased serum lipase, and insomnia.
Key drug/food interactions

Dofetilide, carbamazepine, rifampin, and metformin.
Special considerations

Hepatic impairment Child-Pugh C: Use not recommended..

Class(es)

Fusion protein inhibitor.
Clinical use(s)

FDA approved: HIV.
Mechanism(s) of action

Interferes with the entry of HIV-1 into cells by inhibiting the fusion of viral and cellular membranes. It prevents conformational changes required for fusion of viral and cellular membranes.
Key adverse effects

Injection-site reaction, nausea, vomiting, diarrhea, and fatigue.
Key drug/food interactions

Tipranavir.
Special considerations

Injectable only.

Class(es)

CCR5 antagonist.
Clinical use(s)

FDA approved: HIV (CCR5-tropic positive).
Mechanism(s) of action

The antiviral mechanism of action of maraviroc is exclusively CCR5-mediated by preventing the interaction of HIV-1 glycoprotein (gp)120 and CCR5 necessary for CCR5-tropic HIV-1 to enter cells.
Key adverse effects

Rash, nausea/vomiting, infectious disease, cough, upper respiratory tract infection (URTI), and fever.
Key drug/food interactions

Carbamazepine, fluconazole, and 3A4 inducers/inhibitors.
Special considerations

Boxed Warning (BBW): Hepatotoxicity, severe rash, and systemic allergic reaction.
Renal impairment: CrCl < 30 ml/min + CYP3A inhibitors or inducers—contraindicated.

Class(es)

Nucleoside reverse transcriptase inhibitor.
Clinical use(s)

FDA approved: HIV.
Mechanism(s) of action

By inhibiting HBV polymerase and subsequently reverse transcriptase, entecavir inhibits HBV replication by 3 different mechanisms: base priming, reverse transcription of the negative strand from the pregenomic mRNA, and synthesis of the positive strand of HBV DNA.
Key adverse effects

Nausea, dizziness, headache, fatigue.
Serious: Lactic acidosis and hepatomegaly with steatosis.
Key drug/food interactions

Food may decrease the exposure of entecavir.
Special considerations

BBW: Potential for hepatitis B reactivation and severe acute exacerbations in discontinuation of therapy.
Renal impairment: CrCl < 50 ml/min—dose adjust.