Topical Metronidazole Uses:

• Bacterial vaginosis: It is 

  • 0.75 percent vaginal gel is recommended for the treatment of bacterial vaginosis.
  • Indicated for the treatment of bacterial vaginosis in females under the age of 12 is a vaginal gel with a 1.3 percent concentration.

• Rosacea:

  • Topical: It is recommended for the treatment of rosacea erythema and inflammatory lesions.

• Trichomoniasis:

  • Flagyl cream [Canadian product]: It is used for the treatment of trichomoniasis in females

Topical Metronidazole Dose in Adults:

Topical Metronidazole Dose in the treatment of Bacterial vaginosis: Intravaginal:

• 75 percent (Vandazole): Intravaginally inject one applicatorful (37.5 mg metronidazole) once every day for five days.
• 75 percent (MetroGel-vaginal, other products): Intravaginal administration of one applicatorful (37.5 mg metronidazole) once or twice daily for five days.
• 3 percent (Nuvessa): A single intravaginal dosage of one applicatorful (65 mg metronidazole).

Topical Metronidazole Dose in the treatment of Rosacea:

• 75%: Twice daily application and rubbing of a thin coating. Apply to the entire afflicted area after washing the area first.
• 1 percent: One time each day, apply a thin coating to the afflicted region.

Topical metronidazole dose in the treatment of Trichomoniasis: Intravaginal:

• Insert one applicatorful (equivalent to 500 milligrams of metronidazole) of Flagyl Cream, a Canadian medication, intravaginally once or twice each day.
• Total duration: ten or twenty days straight (even during menses).

How much topical metronidazole should be used to treat bacterial vaginosis in Children?

• Vaginal gel 0.75%:

  • Adolescents: Intravaginal: For five days, administer one applicatorful (37.5 mg metronidazole) intravaginally at bedtime.

• Vaginal gel 1.3%:

  • Children ≥12 years and Adolescents: Intravaginal: One dosage of one applicatorful (65 mg metronidazole) administered intravaginally at night

Topical Metronidazole Dose in the treatment of Periorificial dermatitis:

• Infants ≥6 months, Children, and Adolescents:

  • Topical: Gel with 0.75 percent: One or two times each day, use a thin film.

Pregnancy Risk Factor B

• Vaginal products are generally not recommended for pregnant women. 
• Current guidelines recommend metronidazole to treat symptomatic bacterial vaginosis in pregnancy.
• This is because bacterial vaginosis can lead to adverse pregnancy outcomes.
• The amount that remains after topical application is in the systemic circulation is lower.
• Topical antibiotics such as metronidazole are compatible with pregnancy
• Metronidazole crosses into the placenta, and quickly enters the fetal circulation after oral administration. 

Metronidazole use during breastfeeding:

• After an oral dose, metronidazole is excreted in breast milk. Systemic absorption is not possible after topical or vaginal applications.
• Systemic absorption can be reduced by topical and vaginal applications.
• Research in animal reproduction has shown that breastfeeding infants are at risk of developing cancer. 
• According to the risks to infants and benefits to mothers, some manufacturers recommend that metronidazole be used in lactating women.
• A breastfeeding woman may be willing to give her child formula or breast milk if she is unable to pump and discard her milk during therapy or 24 hours after it stops.
• Other manufacturers recommend that you do not breastfeed during therapy, or for 48 hours following the end of therapy.
• Topical application is usually compatible with breastfeeding

Dose in Kidney Disease:

The manufacturer has not provided any dose adjustment in labeling.

Dose in Liver disease:

The manufacturer has not provided any dose adjustment in labeling; use cautiously if the patient has severe hepatic impairment.

Side Effects of Topical Metronidazole:

• Central nervous system:

  • Headache

• Genitourinary:

  • Urinary tract infection

• Cardiovascular:

  • Hypertension
•  

• Hypersensitivity:

  • Local hypersensitivity reaction

• Infection:

  • Influenza

• Dermatologic:

  • Pruritus
  • Skin irritation
  • Stinging of the skin
  • Erythema
  • Contact dermatitis
  • Xeroderma
  • Burning sensation of skin
  • Exacerbation of acne rosacea
•  

• Respiratory:

  • Upper respiratory tract infection

Frequency of side effects not defined:

• Central nervous system:

  • Metallic taste
  • Numbness of extremities
  • Tingling of extremities

• Gastrointestinal:

  • Nausea

• Ophthalmic:

  • Lacrimation

Vaginal:

Common Side Effects of Topical Metronidazole:

• Genitourinary:

  • Vaginal discharge

• Infection:

  • Fungal infection

Less Common Side Effects of Topical Metronidazole:

• Gastrointestinal:

  • Vomiting
  • Gastrointestinal Distress
  • Abdominal Pain
  • Nausea
  • Decreased Appetite
  • Diarrhea
  • Dysgeusia
  • Abdominal Cramps

• Central Nervous System:

  • Headache
  • Dizziness

• Dermatologic:

  • Pruritus
  • Skin Rash

• Hematologic & Oncologic:

  • Abnormal White Blood Cell Differential

• Neuromuscular & Skeletal:

  • Muscle Cramps

• Genitourinary:

  • Vulvovaginal Irritation
  • Pelvic Pain
  • Vulvovaginal Candidiasis
  • Cervical Candidiasis
  • Vaginitis
  • Abnormal Uterine Bleeding
  • Dysmenorrhea
  • Vulvovaginal Pruritus
  • Mastalgia

• Infection:

  • Infection

• Respiratory:

  • Pharyngitis

Contraindications to Topical Metronidazole :

• Hypersensitivity to any component of metronidazole formulation, parabens, or their components
• Alcohol and propylene glycol are acceptable throughout therapy and for up to 24 hours after stopping it (vaginal Gel only).
• Disulfiram should not be used within the last 2 weeks (vaginal gel only).

Flagyl cream [Canadian Product]: Additional contraindications

• Active neurological disorders
• Hypothyroidism and hypoadrenalism.
• History of blood dyscrasia

Additional contraindications to Nidagel [Canadian Product]

• During the first trimester.

Warnings and precautions

• Carcinogenic:

  • Its potential carcinogenicity has been shown in animal data. Use only after proper authorization.

• CNS effects

  • Numerous CNS side effects, such as aseptic meningitis and encephalopathy, seizures, and neuropathies, can be brought on by systemic metronidazole (peripheral or optic). Topical use may result in peripheral neuropathy.
  • CNS diseases should be treated with caution
  • If the patient experiences any unusual neurologic signs, discontinue treatment immediately.

• Eye irritation:

  • It can cause irritation to the eyes. Avoid contact with it as it could cause tears.
  • If you accidentally become exposed, wash right away.

• Superinfection

• • Long-term use can lead to fungal or bacterial superinfection.
  • Candida vaginalis can occur in approximately 6% to 10% of women after vaginal gel treatment.

• Hepatic impairment

  • It is important to be cautious if you have severe liver impairment.
•  

• Blood dyscrasias:

  • If the patient has a history or blood dyscrasias, use caution.

Metronidazole (topical): Drug Interaction

How to use topical metronidazole?

Topical:

• The topical application does not produce a disulfiram-like effect.
• Use on dry, clean skin. After application, cosmetics can be utilized (wait at least 5 minutes after using lotion).

Intravaginal:

• Only for vaginal use. Apply with an applicator in any relaxed position.
• Holding the applicator by the barrel, gently push it as deep into the vagina as you can without hurting yourself.
• Push the plunger until it stops and the applicator is removed. throw away after usage
• During the course of the therapy, refrain from using any other intravaginal items (such as tampons or douches) or having vaginal contact.

0.75%:

• Administer once in the morning and evening if being used in BID dose; if daily, use at bedtime.

1.3%:

• Administer as a single dose at bedtime.

10% (Flagyl cream [Canadian product]):

• Administer once or twice a day; use of applicator after the 7 months of pregnancy is not recommended.

Mechanism of action of Metronidazole:

When it interacts with bacterial DNA, it can result in strand breaks or loss of helical DNA structure. In turn, this prevents protein synthesis and results in cell death.

Absorption

• Topical:
  • The systemic concentrations after the application of 1 g of topical cream and gel are less than those after 250 mg of oral dosing
• Vaginal gel:
  • Systemic concentrations after 5g of vaginal gel (containing either 37.5m or 65m metronidazole), are approximately 2 % lower than those achieved after 500 mg oral dosage

International Brand Names of Metronidazole Topical:

• MetroCream
• Vandazole
• Flagyl
• Nidagel
• Acea Gel
• Epaq
• Geloderm
• Li Fu
• Metroderme
• MetroGel-Vaginal
• MetroLotion
• Metrogyl
• Metrogyl Gel
• Metrosa
• Nidazea
• Robaz
• Rosaced gel
• Rosagel
• Rosiced
• Roza
• Metrogel
• Noritate
• Nuvessa
• Rosadan
• Rozacreme
• Rozagel
• Rozamet
• Rozex
• Trogel
• Zidoval
• Zyomet Gel

Metronidazole Brand Names in Pakistan: