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Metronidazole Dosage

Medically reviewed by Drugs.com. Last updated on Apr 11, 2019.

Applies to the following strengths: 500 mg; 250 mg; 375 mg; 750 mg; 500 mg/100 mL; benzoate; 50 mg/mL; 100 mg/mL

Usual Adult Dose for Bacterial Infection

Loading dose: 15 mg/kg IV once as a single dose
Maintenance dose: 7.5 mg/kg IV or orally every 6 hours
Maximum dose: 4 g/day
Usual duration of therapy: 7 to 10 days

Comments:
-Most serious anaerobic infections are treated with IV therapy initially.
-Loading and maintenance doses should be infused IV over 1 hour.
-The first IV maintenance dose should be started 6 hours after the start of the loading dose.
-May switch from IV to oral therapy when conditions warrant, based on severity of disease and patient response to IV therapy
-Infections of the lower respiratory tract and endocardium may require longer treatment.

Uses: For the treatment of serious infections due to susceptible anaerobic bacteria including:
-Gynecologic infections (including endometritis, endomyometritis, tubo-ovarian abscess, postsurgical vaginal cuff infection) due to Bacteroides species (including Bacteroides fragilis group [B fragilis, B distasonis, B ovatus, B thetaiotaomicron, B. vulgatus]), Clostridium species, Peptococcus species, Peptostreptococcus species, or Fusobacterium species
-Bacterial septicemia due to Bacteroides species (including B fragilis group) or Clostridium species
-CNS infections (including meningitis, brain abscess) due to Bacteroides species (including B fragilis group)
-Lower respiratory tract infections (including pneumonia, empyema, lung abscess) due to Bacteroides species (including B fragilis group)
-Endocarditis due to Bacteroides species (including B fragilis group)

Usual Adult Dose for Intraabdominal Infection

Loading dose: 15 mg/kg IV once as a single dose
Maintenance dose: 7.5 mg/kg IV or orally every 6 hours
Maximum dose: 4 g/day
Usual duration of therapy: 7 to 10 days

Comments:
-Most serious anaerobic infections are treated with IV therapy initially.
-Loading and maintenance doses should be infused IV over 1 hour.
-The first IV maintenance dose should be started 6 hours after the start of the loading dose.
-May switch from IV to oral therapy when conditions warrant, based on severity of disease and patient response to IV therapy

Uses: For the treatment of serious intraabdominal infections (including peritonitis, intraabdominal abscess, liver abscess) due to susceptible Bacteroides species (including B fragilis group), Clostridium species, Eubacterium species, Peptococcus species, or Peptostreptococcus species

Infectious Diseases Society of America (IDSA) and Surgical Infection Society (SIS) Recommendations: 500 mg IV every 8 to 12 hours or 1500 mg IV every 24 hours

Comments:
-With other antibacterial agents, recommended as a combination regimen for empiric treatment of complicated intraabdominal infection
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Peritonitis

Loading dose: 15 mg/kg IV once as a single dose
Maintenance dose: 7.5 mg/kg IV or orally every 6 hours
Maximum dose: 4 g/day
Usual duration of therapy: 7 to 10 days

Comments:
-Most serious anaerobic infections are treated with IV therapy initially.
-Loading and maintenance doses should be infused IV over 1 hour.
-The first IV maintenance dose should be started 6 hours after the start of the loading dose.
-May switch from IV to oral therapy when conditions warrant, based on severity of disease and patient response to IV therapy

Uses: For the treatment of serious intraabdominal infections (including peritonitis, intraabdominal abscess, liver abscess) due to susceptible Bacteroides species (including B fragilis group), Clostridium species, Eubacterium species, Peptococcus species, or Peptostreptococcus species

Infectious Diseases Society of America (IDSA) and Surgical Infection Society (SIS) Recommendations: 500 mg IV every 8 to 12 hours or 1500 mg IV every 24 hours

Comments:
-With other antibacterial agents, recommended as a combination regimen for empiric treatment of complicated intraabdominal infection
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Liver Abscess

Loading dose: 15 mg/kg IV once as a single dose
Maintenance dose: 7.5 mg/kg IV or orally every 6 hours
Maximum dose: 4 g/day
Usual duration of therapy: 7 to 10 days

Comments:
-Most serious anaerobic infections are treated with IV therapy initially.
-Loading and maintenance doses should be infused IV over 1 hour.
-The first IV maintenance dose should be started 6 hours after the start of the loading dose.
-May switch from IV to oral therapy when conditions warrant, based on severity of disease and patient response to IV therapy

Uses: For the treatment of serious intraabdominal infections (including peritonitis, intraabdominal abscess, liver abscess) due to susceptible Bacteroides species (including B fragilis group), Clostridium species, Eubacterium species, Peptococcus species, or Peptostreptococcus species

Infectious Diseases Society of America (IDSA) and Surgical Infection Society (SIS) Recommendations: 500 mg IV every 8 to 12 hours or 1500 mg IV every 24 hours

Comments:
-With other antibacterial agents, recommended as a combination regimen for empiric treatment of complicated intraabdominal infection
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Joint Infection

Loading dose: 15 mg/kg IV once as a single dose
Maintenance dose: 7.5 mg/kg IV or orally every 6 hours
Maximum dose: 4 g/day
Usual duration of therapy: 7 to 10 days

Comments:
-Most serious anaerobic infections are treated with IV therapy initially.
-Loading and maintenance doses should be infused IV over 1 hour.
-The first IV maintenance dose should be started 6 hours after the start of the loading dose.
-May switch from IV to oral therapy when conditions warrant, based on severity of disease and patient response to IV therapy
-Infections of the bone and joint may require longer treatment.

Uses: As adjunctive therapy for the treatment of bone and joint infections due to Bacteroides species (including B fragilis group)

IDSA Recommendations: 500 mg orally 3 to 4 times a day

Comments:
-This drug can be used in the initial treatment of native vertebral osteomyelitis due to Bacteroides species and other susceptible anaerobes.
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Osteomyelitis

Loading dose: 15 mg/kg IV once as a single dose
Maintenance dose: 7.5 mg/kg IV or orally every 6 hours
Maximum dose: 4 g/day
Usual duration of therapy: 7 to 10 days

Comments:
-Most serious anaerobic infections are treated with IV therapy initially.
-Loading and maintenance doses should be infused IV over 1 hour.
-The first IV maintenance dose should be started 6 hours after the start of the loading dose.
-May switch from IV to oral therapy when conditions warrant, based on severity of disease and patient response to IV therapy
-Infections of the bone and joint may require longer treatment.

Uses: As adjunctive therapy for the treatment of bone and joint infections due to Bacteroides species (including B fragilis group)

IDSA Recommendations: 500 mg orally 3 to 4 times a day

Comments:
-This drug can be used in the initial treatment of native vertebral osteomyelitis due to Bacteroides species and other susceptible anaerobes.
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Skin or Soft Tissue Infection

Loading dose: 15 mg/kg IV once as a single dose
Maintenance dose: 7.5 mg/kg IV or orally every 6 hours
Maximum dose: 4 g/day
Usual duration of therapy: 7 to 10 days

Comments:
-Most serious anaerobic infections are treated with IV therapy initially.
-Loading and maintenance doses should be infused IV over 1 hour.
-The first IV maintenance dose should be started 6 hours after the start of the loading dose.
-May switch from IV to oral therapy when conditions warrant, based on severity of disease and patient response to IV therapy.

Use: For the treatment of serious skin and skin structure infections due to susceptible Bacteroides species (including B fragilis group), Clostridium species, Peptococcus species, Peptostreptococcus species, or Fusobacterium species

IDSA Recommendations:
-Incisional surgical site infection: 500 mg IV every 8 hours
-Necrotizing infection: 500 mg IV every 6 hours
-Infection after animal bite:
---IV: 500 mg IV every 8 hours
---Oral: 250 to 500 mg orally 3 times a day

Comments:
-With ceftriaxone, ciprofloxacin, or levofloxacin, recommended as a combination regimen for treatment of incisional surgical site infections after intestinal or genitourinary tract surgery
-With ceftriaxone, ciprofloxacin, or levofloxacin, recommended for treatment of incisional surgical site infections after surgery of axilla or perineum; coverage for methicillin-resistant S aureus (MRSA) may be needed.
-In combination with cefotaxime, recommended for the treatment of necrotizing infections of the skin, fascia, and muscle due to mixed infections
-Recommended for the treatment of infection after animal bite; should consider that this drug has no activity against aerobes
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Skin and Structure Infection

Loading dose: 15 mg/kg IV once as a single dose
Maintenance dose: 7.5 mg/kg IV or orally every 6 hours
Maximum dose: 4 g/day
Usual duration of therapy: 7 to 10 days

Comments:
-Most serious anaerobic infections are treated with IV therapy initially.
-Loading and maintenance doses should be infused IV over 1 hour.
-The first IV maintenance dose should be started 6 hours after the start of the loading dose.
-May switch from IV to oral therapy when conditions warrant, based on severity of disease and patient response to IV therapy.

Use: For the treatment of serious skin and skin structure infections due to susceptible Bacteroides species (including B fragilis group), Clostridium species, Peptococcus species, Peptostreptococcus species, or Fusobacterium species

IDSA Recommendations:
-Incisional surgical site infection: 500 mg IV every 8 hours
-Necrotizing infection: 500 mg IV every 6 hours
-Infection after animal bite:
---IV: 500 mg IV every 8 hours
---Oral: 250 to 500 mg orally 3 times a day

Comments:
-With ceftriaxone, ciprofloxacin, or levofloxacin, recommended as a combination regimen for treatment of incisional surgical site infections after intestinal or genitourinary tract surgery
-With ceftriaxone, ciprofloxacin, or levofloxacin, recommended for treatment of incisional surgical site infections after surgery of axilla or perineum; coverage for methicillin-resistant S aureus (MRSA) may be needed.
-In combination with cefotaxime, recommended for the treatment of necrotizing infections of the skin, fascia, and muscle due to mixed infections
-Recommended for the treatment of infection after animal bite; should consider that this drug has no activity against aerobes
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Wound Infection

Loading dose: 15 mg/kg IV once as a single dose
Maintenance dose: 7.5 mg/kg IV or orally every 6 hours
Maximum dose: 4 g/day
Usual duration of therapy: 7 to 10 days

Comments:
-Most serious anaerobic infections are treated with IV therapy initially.
-Loading and maintenance doses should be infused IV over 1 hour.
-The first IV maintenance dose should be started 6 hours after the start of the loading dose.
-May switch from IV to oral therapy when conditions warrant, based on severity of disease and patient response to IV therapy.

Use: For the treatment of serious skin and skin structure infections due to susceptible Bacteroides species (including B fragilis group), Clostridium species, Peptococcus species, Peptostreptococcus species, or Fusobacterium species

IDSA Recommendations:
-Incisional surgical site infection: 500 mg IV every 8 hours
-Necrotizing infection: 500 mg IV every 6 hours
-Infection after animal bite:
---IV: 500 mg IV every 8 hours
---Oral: 250 to 500 mg orally 3 times a day

Comments:
-With ceftriaxone, ciprofloxacin, or levofloxacin, recommended as a combination regimen for treatment of incisional surgical site infections after intestinal or genitourinary tract surgery
-With ceftriaxone, ciprofloxacin, or levofloxacin, recommended for treatment of incisional surgical site infections after surgery of axilla or perineum; coverage for methicillin-resistant S aureus (MRSA) may be needed.
-In combination with cefotaxime, recommended for the treatment of necrotizing infections of the skin, fascia, and muscle due to mixed infections
-Recommended for the treatment of infection after animal bite; should consider that this drug has no activity against aerobes
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Amebiasis

Acute intestinal amebiasis: 750 mg orally 3 times a day for 5 to 10 days
Amebic liver abscess: 500 or 750 mg orally 3 times a day for 5 to 10 days

Comments:
-Aspiration or drainage of pus is still needed for amebic liver abscess.

Uses: For the treatment of acute intestinal amebiasis (acute amebic dysentery) and amebic liver abscess

Usual Adult Dose for Surgical Prophylaxis

Initial preoperative dose: 15 mg/kg IV infused over 30 to 60 minutes and completed about 1 hour before surgery
Followed by: 7.5 mg/kg IV infused over 30 to 60 minutes at 6 and 12 hours after the initial dose

Comments:
-Important to complete administration of initial preoperative dose about 1 hour before surgery to achieve adequate drug levels in serum and tissue at time of initial incision
-Important to administer this drug, if needed, at 6-hour intervals to maintain effective drug levels
-Prophylactic use should be limited to the day of surgery, following the above guidelines; if signs of infection, specimens for culture should be obtained to identify causative organism(s) so that appropriate therapy may be administered.

Use: For surgical prophylaxis, to prevent postoperative infection in contaminated/potentially contaminated colorectal surgery

IDSA, SHEA, American Society of Health-System Pharmacists (ASHP), and SIS Recommendations:
Preoperative dose: 500 mg IV as a single dose

Colorectal surgery prophylaxis: 1 g orally

Comments:
-IV: This drug should be started within 60 minutes before surgical incision.
-IV: A single prophylactic dose is usually sufficient; if prophylaxis is continued postoperatively, duration should be less than 24 hours.
-IV: Redosing may be needed for unusually long procedures.
-Oral: In most patients, mechanical bowl preparation combined with this oral drug plus oral neomycin should be administered in addition to IV prophylaxis; oral regimen should be administered as 3 doses over about 10 hours, beginning after the mechanical bowl preparation, the afternoon and evening before the procedure.
-Coadministration with other agents may be recommended, depending on type of procedure.
-Current guidelines should be consulted for additional information.

Uses: Recommended for surgical prophylaxis for the following procedures:
-Appendectomy for uncomplicated appendicitis
-Biliary tract: Open procedure; elective, high-risk laparoscopic procedure
-Colorectal
-Head and neck: Clean-contaminated cancer surgery; other clean-contaminated procedures (excluding tonsillectomy, functional endoscopic sinus procedures)
-Hysterectomy: Vaginal or abdominal
-Small intestine: Obstructed
-Urologic: Clean-contaminated

Usual Adult Dose for Trichomoniasis

Capsules: 375 mg orally twice a day for 7 consecutive days

Tablets:
-One-day regimen: 2 g orally as a single dose or 1 g twice given in the same day
-Seven-day regimen: 250 mg orally 3 times a day for 7 consecutive days

Comments:
-Single-dose regimens can assure compliance, however, a 7-day course may minimize reinfection by protecting the patient long enough for the sexual contact to be treated.
-The dose regimen should be individualized in females and males; some patients may tolerate 1 regimen more than the other.
-The patient's sexual partner(s) should also be evaluated/treated.
-If repeat courses are required, an interval of 4 to 6 weeks should elapse between courses and the presence of the trichomonad be reconfirmed by appropriate laboratory testing.
-Pregnant patients should not be treated during the first trimester; if alternative therapy was not adequate in a pregnant patient, the 1-day regimen is not recommended (results in higher serum levels which can reach fetal circulation).
-The trichomonad can interfere with accurate assessment of abnormal cytological smears; additional smears should be performed after the parasite is eradicated.
-Whether to treat an asymptomatic male partner with a negative culture (or with no culture) is an individual decision; should consider that a woman may be reinfected if her sexual partner is not treated and that it is considerably difficult to isolate the organism from asymptomatic male carriers so negative smears and cultures cannot be relied upon
-The sexual partner should be treated with this drug if reinfection occurs.

Uses:
-Symptomatic trichomoniasis: For the treatment of Trichomonas vaginalis infection in females and males when confirmed by appropriate laboratory procedures (wet smears and/or cultures)
-Asymptomatic trichomoniasis: For the treatment of asymptomatic T vaginalis infection in females when associated with endocervicitis, cervicitis, or cervical erosion
-Treatment of asymptomatic sexual partners: For the simultaneous treatment of asymptomatic sexual partners of treated patients if T vaginalis is present to prevent reinfection of the partner

US CDC Recommendations: 2 g orally once as a single dose
-Alternative regimen: 500 mg orally twice a day for 7 days

Trichomoniasis in HIV-infected women: 500 mg orally twice a day for 7 days

Treatment failure with single-dose therapy and reinfection is excluded: 500 mg orally twice a day for 7 days
-For patients failing this regimen: 2 g orally once a day for 7 days should be considered

Comments:
-Sexual partner(s) should be treated simultaneously with the same dose; appropriate treatment of sexual partner(s) may increase reported cure rates.
-If treatment is considered, the recommended regimen in pregnant women is 2 g orally as a single dose; symptomatic women, at any stage of pregnancy, should be tested and considered for treatment.
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Bacterial Vaginosis

Extended-release tablets: 750 mg orally once a day for 7 consecutive days

Use: For the treatment of bacterial vaginosis in nonpregnant women

US CDC Recommendations:
-Immediate-release tablets: 500 mg orally twice a day for 7 days

Comments:
-Treatment is recommended for all women with symptoms.
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Pseudomembranous Colitis

IDSA and Society for Healthcare Epidemiology of America (SHEA) Recommendations:
-Initial episode of nonsevere Clostridium difficile infection (CDI): 500 mg orally 3 times a day for 10 to 14 days
-Initial episode of fulminant CDI: 500 mg IV every 8 hours

Comments:
-Oral: Recommended as an alternative agent for an initial episode of nonsevere CDI
-IV: With vancomycin (oral or rectal), recommended for an initial episode of fulminant CDI, especially if ileus is present
-Fulminant CDI may be characterized by hypotension/shock, ileus, or megacolon.
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Helicobacter pylori Infection

American College of Gastroenterology Recommendations:
First-line Regimens for Helicobacter pylori Infection:
-Bismuth quadruple therapy: 250 mg orally 4 times a day or 500 mg orally 3 to 4 times a day
-Clarithromycin-based triple therapy: 500 mg orally 3 times a day
-Concomitant therapy, fluoroquinolone sequential therapy, hybrid therapy, or sequential therapy: 500 mg orally twice a day

Duration of Therapy:
-Bismuth quadruple therapy: 10 to 14 days
-Clarithromycin-based triple therapy: 14 days
-Concomitant therapy: 10 to 14 days
-Fluoroquinolone sequential therapy: 5 to 7 days
-Hybrid therapy: 7 days
-Sequential therapy: 5 to 7 days

Salvage Regimens for H pylori Infection:
-Bismuth quadruple therapy: 500 mg orally 3 to 4 times a day for 14 days
-Concomitant therapy: 500 mg orally 2 to 3 times a day for 10 to 14 days

Comments:
-Bismuth quadruple therapy: Consists of a proton pump inhibitor (PPI), bismuth, tetracycline, and a nitroimidazole
-Clarithromycin-based triple therapy: Consists of a PPI, clarithromycin, and (amoxicillin or this drug)
-Concomitant therapy: Consists of a PPI, clarithromycin, amoxicillin, and a nitroimidazole
-Fluoroquinolone sequential therapy: Consists of a PPI and amoxicillin initially followed by a PPI, a fluoroquinolone, and a nitroimidazole
-Hybrid therapy: Consists of a PPI and amoxicillin initially followed by a PPI, amoxicillin, clarithromycin, and a nitroimidazole
-Sequential therapy: Consists of a PPI and amoxicillin initially followed by a PPI, clarithromycin, and a nitroimidazole
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Pelvic Inflammatory Disease

US CDC Recommendations: 500 mg orally twice a day for 14 days

Comments:
-Recommended as an optional component of IM/oral regimens for mild-to-moderately severe acute pelvic inflammatory disease (PID); regimens include ceftriaxone plus doxycycline (with or without this drug), cefoxitin/probenecid plus doxycycline (with or without this drug), or other parenteral third-generation cephalosporin plus doxycycline (with or without this drug).
-Since anaerobic organisms are suspected in the etiology of PID, the addition of this drug should be considered; also effectively treats bacterial vaginosis, which is often associated with PID.
-Recommended to complete at least 14 days of therapy with doxycycline when tubo-ovarian abscess is present; provides more effective anaerobic coverage than doxycycline alone
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Giardiasis

Some Experts Recommend: 250 mg orally 3 times a day for 5 to 7 days

Comments:
-Recommended as a regimen to treat giardiasis
-Current guidelines should be consulted for additional information.

Usual Adult Dose for STD Prophylaxis

US CDC Recommendations: 2 g orally once as a single dose

Comments:
-With ceftriaxone and azithromycin, recommended as a regimen for sexually transmitted disease (STD) prophylaxis after sexual assault or abuse
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Nongonococcal Urethritis

US CDC Recommendations: 2 g orally once as a single dose

Comments:
-In areas where T vaginalis is prevalent, recommended for recurrent or persistent urethritis in men who have sex with women
-Sexual partners should be referred for evaluation and appropriate treatment.
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Balantidium coli

US CDC Recommendations: 500 to 750 mg orally 3 times a day for 5 days

Comments:
-Recommended as an alternative regimen for balantidiasis due to Balantidium coli
-Current guidelines should be consulted for additional information.

Usual Adult Dose for Dientamoeba fragilis

US CDC Recommendations: 500 to 750 mg orally 3 times a day for 10 days

Comments:
-Recommended as a regimen to treat infection due to Dientamoeba fragilis
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Bacterial Infection

American Academy of Pediatrics (AAP) Recommendations:
Neonates:
Loading dose: 15 mg/kg IV once as a single dose
Maintenance dose:
-Postmenstrual age up to 34 weeks: 7.5 mg/kg IV every 12 hours
-Postmenstrual age 35 to 40 weeks: 7.5 mg/kg IV every 8 hours
-Postmenstrual age greater than 40 weeks: 10 mg/kg IV every 8 hours

1 month or older:
-IV: 22.5 to 40 mg/kg/day IV in 3 or 4 divided doses
---Maximum dose: 4 g/day
-Oral: 15 to 50 mg/kg/day orally in 3 divided doses
Maximum dose: 2.25 g/day

Comments:
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Amebiasis

35 to 50 mg/kg/day orally divided in 3 doses for 10 days

Comments:
-Aspiration or drainage of pus is still needed for amebic liver abscess.

Uses: For the treatment of acute intestinal amebiasis (acute amebic dysentery) and amebic liver abscess

Usual Pediatric Dose for Pseudomembranous Colitis

AAP Recommendations:
1 month or older: 7.5 mg/kg orally (or IV) every 6 hours for 10 days
Maximum dose: 500 mg/dose

IDSA and SHEA Recommendations for Children:
-Initial episode or first recurrence of nonsevere CDI: 7.5 mg/kg orally 3 or 4 times a day
-Initial episode of severe/fulminant CDI: 10 mg/kg IV 3 times a day
Maximum dose: 500 mg/dose
Duration of therapy: 10 days

Comments:
-AAP: Recommended for the first occurrence or first recurrence of mild to moderate CDI (oral formulation preferred)
-AAP: With vancomycin, recommended as IV therapy for the first occurrence of severe and complicated CDI
---Severe and complicated CDI may be characterized by intensive care unit admission, hypotension/shock, pseudomembranous colitis by endoscopy, ileus, or toxic megacolon.
-AAP: This drug should not be used beyond the first recurrence or for chronic therapy due to possible neurotoxicity.
-IDSA and SHEA: Recommended for the oral treatment of children with an initial episode or first recurrence of nonsevere CDI
---If this drug was used for the primary episode, vancomycin should be used for a first recurrence.
-IDSA and SHEA: For severe/fulminant CDI associated with critical illness, the addition of this IV drug to oral vancomycin may be considered.
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Intraabdominal Infection

IDSA and SIS Recommendations: 30 to 40 mg/kg/day IV in divided doses every 8 hours

Comments:
-With other antibacterial agents, recommended as a combination regimen for empiric treatment of complicated intraabdominal infection
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Trichomoniasis

AAP Recommendations:
-Infants and children less than 45 kg: 45 mg/kg/day orally in 3 divided doses for 7 days
---Maximum dose: 2 g/day
-Children at least 45 kg and adolescents: 2 g orally once as a single dose

Comments:
-Recommended for prepubertal vaginitis (sexually transmitted infection [STI] related) due to T vaginalis in infants and children less than 45 kg
-Recommended for vulvovaginitis due to T vaginalis in children at least 45 kg and adolescents
-The patient's sexual partner(s) should be treated simultaneously.
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Nongonococcal Urethritis

AAP Recommendations:
-Children at least 45 kg and adolescents: 2 g orally once as a single dose

Comments:
-In areas where T vaginalis is prevalent, recommended for recurrent or persistent urethritis in males who have sex with females
-Sexual partners should be referred for evaluation and appropriate treatment.
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Bacterial Vaginosis

AAP Recommendations:
-Infants and children less than 45 kg: 15 to 25 mg/kg/day orally in 3 divided doses for 7 days
---Maximum dose: 2 g/day
-Children at least 45 kg and adolescent vulvovaginitis: 500 mg orally twice a day for 7 days

Comments:
-Recommended for prepubertal vaginitis (STI related) due to bacterial vaginosis in infants and children less than 45 kg
-Recommended for vulvovaginitis due to bacterial vaginosis in children at least 45 kg and adolescents
-All females with symptoms should be treated.
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Giardiasis

Some Experts Recommend: 5 mg/kg orally 3 times a day for 5 to 7 days
-Maximum dose: 250 mg/dose

Comments:
-Recommended as a regimen to treat giardiasis
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for STD Prophylaxis

AAP and US CDC Recommendations for Adolescents: 2 g orally once as a single dose

Comments:
-Recommended in combination with ceftriaxone and azithromycin:
---AAP: As a regimen for prophylaxis after sexual victimization in postpubertal adolescents
---US CDC: As a regimen for STD prophylaxis after sexual assault or abuse
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Balantidium coli

AAP and US CDC Recommendations: 35 to 50 mg/kg/day orally in 3 divided doses for 5 days
-Maximum dose: 750 mg/dose

Comments:
-Recommended as an alternative regimen for balantidiasis due to B coli
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Dientamoeba fragilis

AAP Recommendations: 35 to 50 mg/kg/day orally in 3 divided doses for 10 days
-Maximum dose: 750 mg/dose

Comments:
-Recommended as a regimen to treat infection due to D fragilis
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Pelvic Inflammatory Disease

US CDC Recommendations for Adolescents: 500 mg orally twice a day for 14 days

Comments:
-Recommended as an optional component of IM/oral regimens for mild-to-moderately severe acute PID; regimens include ceftriaxone plus doxycycline (with or without this drug), cefoxitin/probenecid plus doxycycline (with or without this drug), or other parenteral third-generation cephalosporin plus doxycycline (with or without this drug).
-Since anaerobic organisms are suspected in the etiology of PID, the addition of this drug should be considered; also effectively treats bacterial vaginosis, which is often associated with PID.
-Recommended to complete at least 14 days of therapy with doxycycline when tubo-ovarian abscess is present, metronidazole with doxycycline is recommended for continued therapy; provides more effective anaerobic coverage than doxycycline alone
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Skin or Soft Tissue Infection

IDSA Recommendations:
1 month or older: 7.5 mg/kg IV every 6 hours
Maximum dose: 500 mg/dose

Comments:
-In combination with cefotaxime, recommended for the treatment of necrotizing infections of the skin, fascia, and muscle due to mixed infections
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Skin and Structure Infection

IDSA Recommendations:
1 month or older: 7.5 mg/kg IV every 6 hours
Maximum dose: 500 mg/dose

Comments:
-In combination with cefotaxime, recommended for the treatment of necrotizing infections of the skin, fascia, and muscle due to mixed infections
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Surgical Prophylaxis

IDSA, SHEA, ASHP, and SIS Recommendations:
Preoperative dose:
-Neonates less than 1.2 kg: 7.5 mg/kg IV as a single dose
-Neonates at least 1.2 kg and pediatric patients 1 month or older: 15 mg/kg IV as a single dose
Maximum dose: 500 mg/dose

Colorectal surgery prophylaxis: 15 mg/kg orally
Maximum dose: 1 g/dose

Comments:
-IV: This drug should be started within 60 minutes before surgical incision.
-IV: A single prophylactic dose is usually sufficient; if prophylaxis is continued postoperatively, duration should be less than 24 hours.
-IV: A single prophylactic dose is usually sufficient; if prophylaxis is continued postoperatively, duration should be less than 24 hours.
-IV: Redosing may be needed for unusually long procedures.
-Oral: In most patients, mechanical bowl preparation combined with this oral drug plus oral neomycin should be administered in addition to IV prophylaxis; oral regimen should be administered as 3 doses over about 10 hours, beginning after the mechanical bowl preparation, the afternoon and evening before the procedure.
-Coadministration with other agents may be recommended, depending on type of procedure.
-Current guidelines should be consulted for additional information.

Uses: Recommended for surgical prophylaxis for the following procedures:
-Appendectomy for uncomplicated appendicitis
-Biliary tract: Open procedure; elective, high-risk laparoscopic procedure
-Colorectal
-Head and neck: Clean-contaminated cancer surgery; other clean-contaminated procedures (excluding tonsillectomy, functional endoscopic sinus procedures)
-Hysterectomy: Vaginal or abdominal
-Small intestine: Obstructed
-Urologic: Clean-contaminated

Renal Dose Adjustments

Mild to moderate renal dysfunction: No adjustment recommended.
Severe renal dysfunction or ESRD (not on hemodialysis): Data not available

Comments:
-Accumulation of metabolites may occur in severe renal dysfunction or ESRD (not on hemodialysis); monitoring for drug-related side effects is recommended.

Liver Dose Adjustments

Mild to Moderate Liver Dysfunction: No adjustment recommended.

Severe Liver Dysfunction (Child-Pugh C):
-Immediate-release tablet, capsule, and IV formulations: Dose should be reduced by 50%.
-Extended-release tablets: Not recommended unless benefits considered to outweigh risks.

Hepatic encephalopathy:
-IV: Reduce dose as needed.

Comments:
-Patients with mild to moderate liver dysfunction should be monitored for drug-related side effects.

Precautions

US BOXED WARNING:
-CARCINOGENICITY: This drug has been shown to be carcinogenic in mice and rats. Unnecessary use should be avoided; use should be reserved for the conditions for which it is indicated.

CONTRAINDICATIONS:
-History of hypersensitivity to the active component or other nitroimidazole derivatives
-Use of disulfiram within the last 2 weeks
-Ingestion of alcohol or products containing propylene glycol during and for at least 3 days after discontinuing therapy
-First trimester of pregnancy in patients with trichomoniasis

Consult WARNINGS section for additional precautions.

Dialysis

Hemodialysis: If use of this drug cannot be separated from hemodialysis session, a supplemental dose after the hemodialysis session should be considered, depending on clinical situation of patient.

Other Comments

Unless otherwise indicated, the immediate-release formulations are indicated for oral therapy.

Administration advice:
-IV: Individualize dosage, rate of administration, and duration of therapy (depend on: indication for use; patient age, weight, clinical condition, concomitant therapy; clinical and laboratory response of patient to therapy).
-IV: Administer via slow IV drip infusion only, either as continuous or intermittent infusion; do not use flexible container in series connections.
-IV: If used with primary IV fluid system, stop the primary solution during infusion of this drug.
-IV: Do not use equipment containing aluminum (e.g., needles, cannulae) that would come in contact with drug solution (precipitates may form).
-Most serious anaerobic infections are treated with IV therapy initially; may switch to oral therapy when conditions warrant, based on severity of disease and patient response to IV therapy
-In general, duration of therapy is 7 to 10 days; infections of the bone and joint, lower respiratory tract, and endocardium may require longer therapy.
-Extended-release tablets: Do not split, crush, or chew; administer at least 1 hour before or 2 hours after meals (under fasting conditions).

Storage requirements:
-Capsules: Store at 15C to 25C (59F to 77F).
-IV solution (in single-dose plastic containers): Store in moisture barrier overwrap at 20 to 25C (68F to 77F) and protect from light during storage; do not refrigerate.
-Tablets: Store below 25C (77F); protect from light.

Reconstitution/preparation techniques:
-The manufacturer product information should be consulted.

IV compatibility:
-Incompatible (includes but not limited to): Aztreonam, cefamandole nafate, cefoxitin, penicillin G
-Additives should not be introduced unless compatibility known.
-Without compatibility studies, this drug must not be mixed with other drugs.

General:
-In mixed aerobic and anaerobic infections, this drug should be used with antimicrobials appropriate for the treatment of aerobic infection.
-To reduce the development of drug-resistant organisms and maintain effective therapy, antibiotics should be used only to treat or prevent infections proven or strongly suspected to be caused by susceptible bacteria.
-Culture and susceptibility information should be considered when selecting/modifying antibacterial therapy or, if no data are available, local epidemiology and susceptibility patterns may be considered when selecting empiric therapy.
-IV solution: Each 100 mL contains 790 mg (14 mEq) of sodium.

Monitoring:
-General: Drug-related side effects in elderly patients, patients with severe renal dysfunction or ESRD not undergoing hemodialysis, peritoneal dialysis patients, and patients with mild to moderate liver dysfunction
-Hematologic: Total and differential leukocyte counts (before and after oral therapy); CBC (before, during, and after prolonged/repeated IV therapy); CBC in patients with blood dyscrasias (with IV therapy)
-Hepatic: Liver function tests in patients with Cockayne syndrome (before starting, within 2 to 3 days after starting, frequently during, and after end of therapy)

Patient advice:
-Avoid missing doses and complete the entire course of therapy.
-Discontinue use of alcoholic beverages or products containing propylene glycol while taking this drug and for at least 3 days after discontinuing use; abdominal cramps, nausea, vomiting, headaches, and flushing may occur.
-Report neurologic symptoms that occur during therapy.
-Patients with Cockayne syndrome: Stop this drug at once and contact healthcare provider if any symptoms of potential liver injury (e.g., abdominal pain, nausea, change in stool color, jaundice) occur.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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