30 - Foundations of Pharmacology: Anti-viral and anti-parasitic drugs

Vocabulary flashcards covering key terms and concepts from the lecture notes on antiviral and antiparasitic drugs (HIV, COVID-19, malaria, Acanthamoeba keratitis).

Virion

A complete virus particle that replicates inside a host cell; uses the host cell’s machinery to produce viral components and contains either DNA or RNA. Often detected at an advanced stage and is difficult to target.

Herpesviruses

DNA viruses that cause diseases such as chickenpox, cold sores, and glandular fever; may have an association with Multiple Sclerosis (evidence is emerging).

Adenoviruses

DNA viruses that commonly cause sore throat, conjunctivitis, and other infections.

Papillomaviruses

DNA viruses that cause warts; can infect skin and mucous membranes.

Orthomyxoviruses

RNA viruses responsible for influenza infections.

Paramyxoviruses

RNA viruses that include measles, mumps, and rubella.

Retroviruses

RNA viruses that reverse-transcribe their genome into DNA and integrate into the host genome (e.g., HIV).

Coronaviruses

RNA viruses including SARS, MERS, and SARS-CoV-2 (COVID-19).

Drug strategies (antiviral therapy)

Antiviral approaches targeting: (1) virus outside the host cell, (2) viral nucleic acid replication, (3) viral nucleic acid integration, (4) viral protein synthesis.

Vaccine

A substance administered to induce an immune response (e.g., modified virus, protein extracts, or mRNA); can reduce disease severity and transmission, but immunity may wane and updated vaccines may be needed for new variants; herd immunity threshold around 60–70%.

Nucleoside Reverse Transcriptase Inhibitors (NRTIs)

NRTIs are nucleoside analogues activated by phosphorylation; they terminate viral DNA chain elongation during replication.

Zidovudine (AZT)

Thymidine analogue NRTI; activated by phosphorylation to Triphosphate; acts as a chain terminator for HIV DNA synthesis.

Emtricitabine

NRTI used in combination antiretroviral therapy for HIV infection.

Tenofovir

NRTI used in HIV therapy; a nucleotide analogue active against HIV replication.

Atazanavir

Protease inhibitor used in HIV therapy to prevent processing of viral polyproteins and maturation of infectious virions.

Ritonavir

Protease inhibitor used to boost other protease inhibitors’ levels by inhibiting their metabolism (PK boosting) in HIV therapy.

Raltegravir

Integrase inhibitor that blocks integration of viral DNA into the host genome in HIV treatment.

Primaquine

8-aminoquinoline used as a tissue schizonticide to kill hypnozoites in the liver (P. vivax and P. ovale); generates oxidative metabolites in hepatocytes.

Hypnozoite

Dormant liver-stage parasite (sporozoites) in P. vivax and P. ovale that can cause relapse of malaria.

Malarone (Atovaquone + Proguanil)

Chemoprophylaxis for malaria: Atovaquone inhibits mitochondrial pyrimidine synthesis; Proguanil inhibits dihydrofolate reductase, reducing DNA synthesis.

Chloroquine

Antimalarial drug of choice in non-resistant areas; blocks haem polymerase in the parasite, preventing haemozoin formation and accumulating in the parasite’s acid vacuole.

Doxycycline

Tetracycline antibiotic used for chloroquine-resistant malaria; possibly affects apicoplast function in the parasite.

Artemisinin-based combination therapy (ACT)

Antimalarial therapy combining artesunate (or artemisinin) with a partner drug to rapidly reduce parasite biomass and prevent resistance.

Acanthamoeba keratitis

Infection of the cornea, often in contact lens wearers; difficult to treat with no licensed monotherapy; managed with topical PHMB and diamidines; can be very painful.

PHMB (polyhexamethylene biguanide)

Polymeric biguanide disinfectant; disrupts the lipid bilayer of Acanthamoeba, causing leakage of cellular contents.

Propamidine

Diamidine used against Acanthamoeba; interferes with polyamine biosynthesis (targets SAMDC) and can intercalate into DNA to inhibit transcription.

Voriconazole

Triazole antifungal used topically for Acanthamoeba keratitis; inhibits ergosterol biosynthesis by targeting CYP51 (lanosterol 14α-demethylase).

Azoles

Class of antifungals that inhibit ergosterol synthesis by blocking lanosterol demethylase (CYP51) in fungal cells.