Medical Pharmacology Chapter 35  Antibacterial Drugs

Previous Page

Sexually Transmitted Diseases--Drug Treatment


Infections to be considered

Chlamydia, including nonchlamydial, nongonococcal urethritis and cervicitis



Pelvic inflammatory disease

Vaginal infection




Genital herpes

  • Chlamydia: Drugs of choice

    • About the organism

    •  Urethritis, cervicitis, conjunctivitis, proctitis

      • Primary drugs:

        •  azithromycin (Zythromax)

          •  single dose usually effective for uncomplicated urethral or cervical infection caused by Chlamydia trachomatis

          •  azithromycin (Zythromax): expensive

          • Or

        •  doxycycline (Vibramycin, Doryx) {alternatives: tetracycline (Achromycin) or minocycline (Minocin)}

          •  seven-day treatment protocol

          •  less costly, patient compliance a concern

      •  Alternative drugs:

        •  ofloxacin (Floxin) { contraindicated in pregnancy)

        •   erythromycin {erythromycin estolate (Ilosone) contraindicated in pregnancy}

    • Nonchlamydial nongonococcal urethritis (NGU) in men

      •  Causative agents: Ureaplasma urealyticum, Mycoplasma genitalium et al.

      •  Treatment: normally responsive to azithromycin (Zythromax) or doxycycline (Vibramycin, Doryx)

        • Alternative treatment: erythromycin or ofloxacin (Floxin)

    • Infection in pregnancy:

      • Primary drug

        •  amoxicillin (Amoxil Polymox)

        •  probably safe/effective

      • Alternative drugs

        •  azithromycin (Zythromax) -- safety and pregnancy not established, but probably safe & effective (limited clinical experience with azithromycin (Zythromax) in pregnancy)

        •  erythromycin {erythromycin estolate (Ilosone) contraindicated in pregnancy}

          • Seven-day erythromycin treatment course may be poorly tolerated by patients -- gastrointestinal effects

      •  Contraindications:

        •  not for use in pregnancy: doxycycline (Vibramycin, Doryx), other tetracycline (Achromycin) and fluoroquinones

    •  Neonatal:  infant conjunctivitis/pneumonia risk if mother has Chlamydia trachomatis

      •  Ophthalmic tetracycline (Achromycin), erythromycin, silver nitrate: not reliable for prevention of newborn ocular chlamydial infection

      • Opthalmia

        •  Primary drug:

          • erythromycin 14 day treatment course

        •  Alternative drug:

          • azithromycin (Zythromax)

      • Pneumonia:

        •  Primary drug:

          • erythromycin

  • Gonorrhea

    • About the organism

    • Drugs of choice

      • Urethral, cervical, rectal, pharyngeal

      • Primary drugs:  highly effective with single, oral doses (uncomplicated anogenital & pharyngeal infection {even with penicillin-and tetracycline (Achromycin)-resistant Neisseria gonorrhoeae )

        •  cefixime (Suprax)

        •  ciprofloxacin (Cipro) (contraindicated in pregnancy)

        •  ofloxacin (Floxin) (contraindicated in pregnancy)

        •  ceftriaxone (Rocephin)-- single injection

        •  Fluoroquinone-resistant Neisseria gonorrhoeae strains (increasingly common in the USA {more common in Asia})-- susceptible to cefixime (Suprax) & ceftriaxone (Rocephin)

      • Alternative drug:

        •  spectinomycin (Trobicin)

          •  unreliable against pharyngeal gonococcal infection; may be used to manage pregnant women allergic to beta-lactam antibiotics

      • Drug Management of gonococcal opthalmia, bacteremia, arthritis, or meningitis in adults and and all gonococcal infection in children

        • Parenteral third-generation cephalosporin, eftriaxone (Rocephin)

      • All gonorrhea patients: should be given azithromycin (Zythromax) Laura doxycycline (Vibramycin, Doryx) for presumptive chlamydial infection

      Reference:"Drugs for Sexually Transmitted Infections", The Medical Letter, vol. 41 (issue 1063), September, 24, 1999, Published by the Medical Letter, Inc, New Rochelle, N.Y.

Previous Page


This Web-based pharmacology and disease-based integrated teaching site is based on reference materials, that are believed reliable and consistent with standards accepted at the time of development. Possibility of human error and on-going research and development in medical sciences do not allow assurance that the information contained herein is in every respect accurate or complete. Users should confirm the information contained herein with other sources. This site should only be considered as a teaching aid for undergraduate and graduate biomedical education and is intended only as a teaching site. Information contained here should not be used for patient management and should not be used as a substitute for consultation with practicing medical professionals. Users of this website should check the product information sheet included in the package of any drug they plan to administer to be certain that the information contained in this site is accurate and that changes have not been made in the recommended dose or in the contraindications for administration.  Advertisements that appear on this site are not reviewed for content accuracy and it is the responsibility of users of this website to make individual assessments concerning this information.  Medical or other information  thus obtained should not be used as a substitute for consultation with practicing medical or scientific or other professionals.