Drugs for Sexually Transmitted Infections (STIs) Flashcards
Treatment of Sexually Transmitted
Infections Most common used drugs to treat STI’s include:
• Ceftriaxone
• Penicillin G
• Azithromycin
• Doxycycline
• Gemifloxacin
• Acyclovir, ganciclovir, foscarnet
• Metronidazole
• Fluconazole
• Imiquimod
HSV self-care measures are
Acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) may also help relieve the
pain of genital ulcers. Self-care measures include local treatments used to relieve the pain of a herpes
outbreak. Sitting in a few inches of warm water can temporarily relieve ulcer
pain.
Acyclovir Mechanism of Action
Acyclovir Mechanism of Action:
• A guanosine derivative that causes DNA chain termination. Activated by viral thymidine kinase
(TK) to a monophosphate form. Host enzymes then convert the monophosphate to di- and then
tri-phosphate (active) form which inhibits the viral DNA polymerase causing chain termination
due to the lack of a 3’ -OH group.
________usually requires more frequent dosing than famciclovir and valacyclovir.
Acyclovir
Three antiviral medications are used to treat genital herpes:
• acyclovir, famciclovir, and
valacyclovir.
________ has the greatest bioavailability (80%) and is rapidly hydrolyzed to ________ after
its absorption.
Famciclovir
penciclovir
________its monophosphate form also incorporates into the viral DNA, resulting in chain
termination.
Valacyclovir
Mycoplasma genitalium: Urethritis, Cervicitis tx
Two-stage therapy approaches: Doxycycline is provided as initial empiric
therapy, which reduces the organism load and facilitates organism clearance,
followed by macrolide-sensitive M. genitalium infections treated with high-dose
Azithromycin; macrolide-resistant infections are treated with Moxifloxacin.
______________lacks a cell wall, and thus antibiotics targeting cell-wall biosynthesis (e.g., ß-lactams including penicillins and cephalosporins) are ineffective against this organism
M. genitalium
Recommended regimens for chlamydial infection among adolescents and adults
Doxycycline 100 mg orally 2 times/day for 7 days
Chlamydial Infections alt regimens
Azithromycin 1 g orally in a single dose or levofloxacin 500 mg orally once daily for 7 days
___________ is an intracellular pathogen that has a
cell wall, in that it lacks peptidoglycan. (beta
lactam antibiotics not effective)
Chlamydia is an intracellular pathogen that has a
cell wall, in that it lacks peptidoglycan. (beta
lactam antibiotics not effective)
Multiple sequelae can result from___________
infection among women, the most serious of
which include PID, ectopic pregnancy, and
infertility
C. trachomatis
Lymphogranuloma Venereum (LGV) recommended regimen & alt regimens
Doxycycline 100 mg orally 2 times/day for 21 days
Azithromycin 1 gm orally once weekly for 3 weeks or
Erythromycin base 500 mg orally 4 times/day for 21 days
• Are a group of broad-spectrum antibiotic compounds
• They have a common basic structure
•________ molecules comprise a linear fused
_______ nucleus (rings designated A, B, C and D) to
which a variety of functional groups are attached
Tetracycline
Chlortetracycline
Oxytetracycline
Demeclocycline
Doxycycline
Minocycline
MOA of Tetracyclines
• Tetracyclines bind reversibly to the
30S subunit and are bacteriostatic
• They block the binding of aminoacyl-
tRNA to the acceptor site on the
mRNA-ribosome complex
• This prevents addition of amino acids
to the growing peptide
Adverse effects of Tetracyclines
• Teeth: permanent brown discoloration & ill formed teeth
• Stunted bone growth
• Phototoxicity on exposure to UV light- demeclocycline,
doxycycline
• Super infections: Diarrhea, Candida
• Epigastric pain, abdominal distention, nausea, vomiting
• Hepatic injury
• Nephrotoxicity- doxycycline safe
• Fanconi’s syndrome: A from of renal tubular acidosis is
attributed to use of outdated tetracyclines
Macrolides he prototype drug is
erythromycin
The main macrolide and related antibiotics are
erythromycin, clarithromycin and azithromycin
MOA of Macrolides
• Bind reversibly to the 50S subunit
• Protein synthesis is inhibited
because aminoacyl translocation
reactions are inhibited
Fluroquinolones examples are
•Examples are Norfloxacin, Ciprofloxacin, and Levofloxacin
MOA of Fluroquinolones
FQs inhibit Bacterial Topoisomerase II (DNA gyrase) and
Topoisomerase IV
• These are responsible for separation of replicated DNA during cell
division
• DNA gyrase has 2 subunits A and B
• Subunit ‘A’ Nicks the double stranded DNA
• Subunit ‘B’ Introduces negative supercoils
• Subunit ‘A’ Reseals the nicked ends
• FQs act by inhibiting bacterial DNA gyrase, after binding to subunit ‘A’ interferes with strand cutting and resealing
Tx of Syphilis
• Treatment: Penicillin G, administered parenterally, is the preferred drug for treating persons in all
stages of syphilis. The preparation used (i.e., benzathine, aqueous procaine, or aqueous crystalline),
dosage, and length of treatment depend on the stage and clinical manifestations of the disease.
• Alternative therapy: Doxycycline
Proctitis, Proctocolitis, and Enteritis
Treatment: Acute proctitis. Ceftriaxone + Doxycycline
