Ametrol

Uses

Vaginal treatment of female urogenital trichomonas infection, prevention & local therapy of candidiasis.

Ametrol is also used to associated treatment for these conditions: Abscess, Intra-Abdominal, Acne Rosacea, Amebiasis, Anaerobic Infection, Bacteremia, Bacterial Endocarditis, Bacterial Peritonitis, Bacterial Vaginosis (BV), Balantidiasis, Bloodstream Infections, Bone and Joint Infections, Brain abscess, CNS Infection, Candidal Vulvovaginitis, Clostridium Difficile Infection (CDI), Empyema, Endometritis, Endomyometritis, Facial Rosacea, Giardiasis, Gynaecological infection, Helicobacter Pylori Infection, Infection, Bacteroides, Intraabdominal Infections, Lower Respiratory Infection, Lower respiratory tract infection bacterial, Lung Abscess, Meningitis, Mixed Vaginal Infections, Parasitic infection NOS, Periodontitis, Pneumonia, Postoperative Infections, Pouchitis, Septicemia bacterial anaerobic, Skin and Subcutaneous Tissue Bacterial Infections, Tetanus, Trichomonal Vaginitis, Trichomonas Vaginitis, Tubo-ovarian abscess, Urethritis, Vulvovaginitis, Asymptomatic Trichomoniasis, Entamoeba histolytica, Hepatic abscess, Refractory Sinusitis, Skin and skin-structure infections, Symptomatic Trichomoniasis, Asymptomatic InfectionsAcne Vulgaris, Dermatophytosis, Dermatophytosis of nail, Diaper Dermatitis, Excessive sweating and body odor, Fungal skin infection, Gastrointestinal candidiasis, Infection Mixed, Infections, Fungal of the Skin Folds, Nail candida, Oropharyngeal Candidiasis, Pityriasis versicolor, Ringworm, Seborrheic Dermatitis, Skin candida, Tinea Capitis, Tinea Corporis, Tinea Cruris, Tinea Pedis, Vaginal Candidiasis, Cutaneous candidiasis

How Ametrol works

The exact mechanism of action of metronidazole has not been fully established, however, it is possible that an intermediate in the reduction of metronidazole which is only made by anaerobic bacteria and protozoa, binds deoxyribonucleic acid and electron-transport proteins of organisms, blocking nucleic acid synthesis. After administration, metronidazole enters cells by passive diffusion. Following this, ferredoxin or flavodoxin reduce its nitro group to nitro radicals. The redox potential of the electron transport portions of anaerobic or microaerophilic microorganisms renders metronidazole selective to these organisms, which cause nitro group reduction, leading to the production of toxic metabolites. These include N-(2-hydroxyethyl) oxamic acid and acetamide, which may damage DNA of replicating organisms.

Miconazole is an azole antifungal used to treat a variety of conditions, including those caused by Candida overgrowth. Unique among the azoles, miconazole is thought to act through three main mechanisms. The primary mechanism of action is through inhibition of the CYP450 14α-lanosterol demethylase enzyme, which results in altered ergosterol production and impaired cell membrane composition and permeability, which in turn leads to cation, phosphate, and low molecular weight protein leakage.

In addition, miconazole inhibits fungal peroxidase and catalase while not affecting NADH oxidase activity, leading to increased production of reactive oxygen species (ROS). Increased intracellular ROS leads to downstream pleiotropic effects and eventual apoptosis.

Lastly, likely as a result of lanosterol demethylation inhibition, miconazole causes a rise in intracellular levels of farnesol. This molecule participates in quorum sensing in Candida, preventing the transition from yeast to mycelial forms and thereby the formation of biofilms, which are more resistant to antibiotics. In addition, farnesol is an inhibitor of drug efflux ABC transporters, namely Candida CaCdr1p and CaCdr2p, which may additionally contribute to increased effectiveness of azole drugs.

Dosage

Ametrol dosage

In trichomoniasis, concurrently with oral metronidazole treatment and 1 vaginal tablet should be inserted high up into the vagina once a day (preferably before going to bed at night) for 10 days. Long-term recovery may be expected only is response to the simultaneous oral treatment ofboth partners.

In candidiasis or other fungal infections, 1 vaginal tablet has to be inserted high up into the vagina for 10 days. The vaginal tablet should be slightly moistened before application.

Side Effects

Nausea, vomiting, febrile reactions, rash, drowsiness, diarrhoea, anorexia and flushing, hepatitis. Local irritation and sensitisation, contact dermatitis.

Toxicity

LD50 information

The oral LD50 of metronidazole in rats is 5000 mg/kg

Overdose information

Adverse effects that may be exaggerated with an overdose include peripheral neuropathy, central nervous system toxicity, seizures, disulfiram-like effect (if combined with alcohol) dark urine, a metallic taste in the mouth, nausea, epigastric discomfort, and vertigo, in addition to neutropenia. There is no specific antidote for metronidazole overdose. Symptomatic and supportive treatment should be employed in addition to the administration of activated charcoal to remove the unabsorbed drug from the gastrointestinal tract. In addition to the above measures, contact the local poison control center for updated information on the management of a metronidazole overdose.

Miconazole overdose has not been reported. Patients experiencing an overdose are at an increased risk of severe adverse effects such as headache, skin irritation, diarrhea, nausea, vomiting, abdominal pain, and dysgeusia. Symptomatic and supportive measures are recommended.

Miconazole has an oral LD₅₀ of 500 mg/kg in rats.

Precaution

For external use only; discontinue if sensitization or irritation occurs. Pregnancy and lactation

Interaction

Metronidazole: Disulfiram-like reaction with alcohol. Increased oral anticoagulant effect, blood levels of phenytoin, lithium toxicity, plasma cone of astemizole & terfenadine; blood cone of carbamazepine. Decreased blood levels with phenobarb. Risk of CNS-related effects (eg psychotic reactions) with disulfiram. Increased blood levels & neurologic effects with cimetidine. May increase blood levels & toxicity of fluorouracil; toxicity of cyclosporine. Increased cardiotoxicity with amiodarone. Interference with blood levels of liver enzymes, glucose (hexokinase method), theophylline & procainamide. Decreased levels with phenytoin.

Miconazole: Increased risk of bleeding with acenocoumarol, anisindione, dicumarol, phenindione, phenprocoumon, warfarin; plasma cone & exposure to oxybutinin.

May increase risk of phenytoin, phosphenytoin, cyclosporine, trimetrexate toxicity & cardiotoxicity with pimozide. May inhibit metabolism of astemizole, cisapride & terfenadine. Reduced carbamazepine metabolism. Increased or prolonged effects of opioid (fentanyl). May cause hypoglycemia with glimepiride. Reduced clearance & increased plasma cone of oxycodone. May increase bioavailability of tolterodine (in patients with deficient CYP2D6 activity).

Volume of Distribution

Metronidazole is widely distributed throughout the body and various body fluids. They include the bile, saliva, breastmilk, cerebrospinal fluid, and the placenta. Steady-state volume distribution of metronidazole in adults ranges from 0.51 to 1.1 L/kg. It attains 60 to 100% of plasma concentrations in various tissues, such as the central nervous system, however, is not measured in high concentrations in the placental tissue.

A 1200 mg miconazole vaginal suppository resulted in a calculated apparent volume of distribution of 95 546 L while a 100 mg vaginal cream yielded an apparent volume of distribution of 10 911L.

Elimination Route

After the intravenous infusion of a 1.5g dose, peak concentration was reached within 1 hour and was peak level of 30-40 mg/L. When a multiple-dose regimen of 500mg three times a day administered intravenously, steady-state concentrations were achieved within about 3 days and peak concentration was measured at 26 mg/L. When administered orally in the tablet form, metronidazole is absorbed entirely absorbed, showing a bioavailability of greater than 90%. One resource indicates that Cmax after a single oral dose of 500mg metronidazole ranges from 8 to 13 mg/L, with a Tmax of 25 minutes to 4 hours. The AUC following a single 500mg oral dose of metronidazole was 122 ± 10.3 mg/L • h.

A note on the absorption of topical preparations

Insignificant percutaneous absorption of metronidazole occurs after the application of 1% metronidazole cream topically. Healthy volunteers applied one 100 mg dose of 14C-labelled metronidazole 2% cream to unbroken skin. After 12 hours, metronidazole was not detected in the plasma. Approximately 0.1% to 1% of the administered metronidazole was measured in the urine and feces.

Miconazole given to healthy volunteers as a single 50 mg oral tablet produced a mean C_max of 15.1 ± 16.2 mcg/mL, a mean AUC_0-24 of 55.2 ± 35.1 mcg*h/mL, and a median T_max of 7 hours (range 2.0-24.1). In these patients measurable plasma concentrations ranged from 0.5 to 0.83 mcg/mL.

Topical miconazole is absorbed poorly into the systemic circulation. In pediatric patients aged 1-21 months given multiple topical applications of miconazole ointment for seven days, the plasma miconazole concentration was less than 0.5 ng/mL in 88% of the patients, with the remaining patients having a concentration of 0.57 and 0.58 ng/mL, respectively. Similarly, patients. administered with a vaginal 1200 mg ovule had a mean C_max of 10.71 ng/mL, mean T_max of 18.4 hours, and mean AUC_0-96 of 477.3 ng*h/mL.

Half Life

The elimination half-life of metronidazole is 7.3 ± 1.0 after a single 500mg IV dose in healthy subjects. Another resource indicates that the elimination half-life for metronidazole ranges from 6 to 10 hours.

Miconazole has a terminal half-life of 24 hours.

Clearance

Dose adjustments may be required in patients with hepatic impairment, as clearance is impaired in these patients. The clearance of metronidazole in the kidneys is estimated at 10 mL/min/1.73 m2. The total clearance from serum is about 2.1 to 6.4 L/h/kg.

Elimination Route

Metronidazole and metabolites are 60 to 80% eliminated in the urine, and 6-15% excreted in the feces.

Miconazole is excreted through both urine and feces; less than 1% of unchanged miconazole is recovered in urine.

Pregnancy & Breastfeeding use

Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women OR Animal studies have shown an adverse effect, but adequate and well-controlled studies in pregnant women have failed to demonstrate a risk to the fetus in any trimester.

Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks

Contraindication

Hypersensitivity; hepatic impairment (oral gel). Porphyria.

Acute Overdose

In general, Miconazole is not highly toxic. In the event of accidental overdosage, vomiting and diarrhoea may occur.

Storage Condition

Store in a cool and dry place. Protect from light and moisture. Keep out of the reach of children

Store away from direct heat. Keep out of reach of children.

Innovators Monograph

You find simplified version here Ametrol