Showing posts with label Antiviral. Show all posts
Showing posts with label Antiviral. Show all posts


Fomivirsen (Vitravene)

  • antisense oligonucleotide (ASO) used specifically to treat retinitis (inflammation of the retina) caused by an infection with cytomegalovirus (CMV) in immunocompromised patients, particularly those with AIDS
    • CMV retinitis can progress to blindness, which sucks
    • CMV belongs to the same family as the viruses that cause chickenpox and herpes, and gets its name from the fact that it produces very large (-mega-) cells (cyto-)
    • most people become infected with CMV at some point in their lives, and it then sticks around for the rest of their lives, but a normal functioning immune system can usually keep it down such that it remains harmless
  • is injected directly into the vitreous humour of the eye (awesome and gross at the same time!) by an ophthalmologist (eye surgeon, often one who has specialized in vitreoretinal surgery)
  • reduces the levels of viral mRNA transcribed from certain immediate-early CMV genes, which in turn reduces the levels of the proteins that they encode
    • these proteins are required for viral replication and viral invasion of host cells and so these processes are disrupted by the drug
  • its unique mechanism of action makes it effective against varieties of CMV that are resistant to traditional antiviral drugs (traditional meaning drugs that aren't nucleic acids like ganciclovir and foscarnet)
Jason TL, Koropatnick J, Berg RW. Toxicology of antisense therapeutics. Toxicol Appl Pharmacol. 2004 Nov 15;201(1):66-83.


Podophyllotoxin (Podofilox)

  • non-alkaloid lignan toxin present in podophyllin, resin produced by the rhizomes of plants belonging to the genus Podophyllum, for which it and the aforementioned resin are named, as well as a number of other genera that I don't feel like listing since I'm pretty sure most of you don't care that much and I really, really want to avoiding bogging down my posts with boring information and hideously long-winded sentences
    • plants containing lignans are commonly found in traditional medicine, making them interesting starting points for the development of new drugs
    • the genus Podophyllum includes Podophyllum peltatum (American Mayapple), a perennial herb native to eastern North America that grows in colonies
  • is used as a topic antiviral agent in the treatment of condyloma acuminatum (genital warts!) caused by human papilloma virus as well as other types of warts found on one's naughty bits
  • has also been used in the treatment of psoriasis vulgaris and rheumatoid arthritis
  • kills cancer cells but was found to be too toxic in mice in preclinical trials, the step in drug development when compounds are evaluated in animals before trying them out in humans
    • etoposide, teniposide, and etopophos are anticancer drugs derived from podophyllotoxin that permanently inactivate DNA topoisomerase II, resulting in DNA strand breaks (i.e. damage) that eventually lead to cell death, but have no effects on the polymerization of tubulin
Gordaliza M et al. Podophyllotoxin: distribution, sources, applications and new cytotoxic derivatives. Toxicon. 2004 Sep 15;44(4):441-59.


Oseltamivir (Tamiflu)

Ladies and gents, I have acquired for my own personal use a flu bug. Posts will resume when I can get out of bed. Cheers.

Update: I can eat solid food once again! Yes!

Thank you for all your kind words, readers!

Some factoids about our good friend oseltamivir:

  • used to fix people with the flu (the flu being an infection with the influenza virus, not a bacterial gastroenteritis, natch)
    • used in those who: (a) aint none too good at fighting infections (babies, kids, old folks, etc.) or (b) are infected with crazy deadly strains of the influenza virus
    • works against both Influenzavirus A (the one that keeps on mutating and causing all these pandemic scares) and Influenzavirus B (the one that pretty much just keeps to itself, oh, and makes people wonderfully miserable during that special time in the winter)
  • inhibits neuraminidase, a viral enzyme that the bugs need to escape from cells after they infect and multiply like crazy inside them
  • given the current limited supplies of this drug, it could be potentially given along with probenecid, a drug that inhibits the elimination of oseltamivir from the body via the kidneys (urine), in order to stretch supplies
    • probenecid was used in this manner to deal with a limited supply of penicillin during the Second World War
  • recently reported to have caused a number of Japanese kids to go nuts (hallucinations and delirium)
  • got myself ten boxes of this bad boy in the fallout shelter out back fer when the Bird Flu drops its mighty payload of retribution on the world's populace



  • trade name is Aldara (5% topical cream)
  • topical immunomodulator (applied to and acts only on the superficial layers of the skin to modify the local immune response)
  • used to treat external genital warts (oh great, another addition to my list of MEDICAL CONDITIONS I REALLY REALLY DON'T WANT TO GET EVER), actinic keratoses (a skin condition that often precedes the development of skin cancer), and superficial skin cancers (basal cell and squamous cell carcinomas and melanoma that appear as a red scaling patch on the skin)
  • increases the production of cytokines (signalling molecules that are similar in function to hormones), which activate the immune system (both innate and adaptive immunity), thus increasing the ability of the body (specifically, the skin) to deal with viral infections and cancerous growths
  • since it has a relatively non-specific mechanism of action, it is likely also effective against other viral infections of the skin and superficial skin cancers
  • may soon find work as an anti-aging agent since it has been shown to repair chronically sun-damaged skin associated with lentigo maligna (melanoma that hasn't begun to spread)



  • also known to those who hate the letter 'y' (I know you're listening, Britain!) as valaciclovir
  • trade name is Valtrex (see: Paris Hilton)
  • is a prodrug, meaning that it is converted into acyclovir, the drug that actually does drug stuff, once it is absorbed into the body
  • is active against both types of the herpes simplex virus (both can cause blistering of the mouth and/or genitals) and the varicella zoster virus (VZV, causes chickenpox when you first get infected with it, then it goes into hiding and is reactivated in some people in later life to produce herpes zoster, or shingles)
  • doesn't curve these viral infections (there is no cure...mwahahahaha) but can reduce duration of symptoms and promote healing
  • is a nucleoside analog, meaning that it mimics the basic components of DNA and RNA in order to mess with the replication and spread of the aforementioned viruses
Kalant H, Grant D, and Mitchell J. Principles of Medical Pharmacology 7th ed. Toronto: Saunders Canada, 2006.