Treatment of acyclovir-resistant herpes simplex and varicella zoster virus infections

Synthesis of Fluorinated Nucleosides/Nucleotides and Their Antiviral Properties

The FDA has approved several drugs based on the fluorinated nucleoside pharmacophore, and numerous drugs are currently in clinical trials. Fluorine-containing nucleos(t)ides offer significant antiviral and anticancer activity. The insertion of a fluorine atom, either in the base or sugar of nucleos(t)ides, alters its electronic and steric parameters and transforms the lipophilicity, pharmacodynamic, and pharmacokinetic properties of these moieties. The fluorine atom restricts the oxidative metabolism of drugs and provides enzymatic metabolic stability towards the glycosidic bond of the nucleos(t)ide. The incorporation of fluorine also demonstrates additional hydrogen bonding interactions in receptors with enhanced biological profiles. The present article discusses the synthetic methodology and antiviral activities of FDA-approved drugs and ongoing fluoro-containing nucleos(t)ide drug candidates in clinical trials.

10: Herpes simplex and varicella-zoster virus infections

Any new patient with suspected genital herpes should have diagnostic testing with virus identification. Type-specific serological tests that distinguish between antibodies for type 1 and type 2 herpes simplex virus (HSV) may be useful to determine previous exposure but cannot be used to diagnose recurrences of genital herpes. Initial episodes of genital herpes usually require antiviral therapy, while recurrences may be treated with continuous antiviral suppression (if frequent) or episodic therapy; patient counselling and education (including how to recognise lesions) are essential. Topical or systemic therapy is available for initial and recurrent non-genital herpes simplex. Primary varicella infection (chickenpox) and herpes zoster (shingles) are usually diagnosed clinically, but can be confirmed by detection of varicella-zoster virus antigens or nucleic acid from swabs of lesions or by antibody tests. Antiviral therapy should be considered in chickenpox if disease is complicated or the patient is immunocompromised. In herpes zoster, antiviral therapy should be given within 72 hours of onset to patients aged over 50 years or with severe pain or neurological abnormalities to reduce the likelihood and duration of postherpetic neuralgia. The availability of effective antiviral therapy makes early diagnosis vital