Description
Ornidazole is prescribed for the treatment of certain protozoan infections, post-surgery infections and bacterial infections. The action of this drug is based on its potential to inhibit the development of microorganisms. Ornidazole is available as an oral tablet that should be taken based on a pharmacist/doctor’s instructions. Prescriptions that include this drug should also take into consideration some of the patient’s specifications such as hypersensitivity and potential drug interactions.
Indications
Ornidazole is given to patients who have vaginal infections such as bacterial vaginitis, post-surgical infections, anaerobic bacterial infections, skin infections, trichomonas vaginitis, intestinal infections, stomach infections, parasitic infections and bacterial infections. It is highly recommended that this drug is taken under appropriate diagnosis and medical indication.
Contraindications
It is not recommended to take this medicine if one is hypersensitive to similar antibiotics, or if one has a history of hypersensitivity. Other than hypersensitivity, this drug is contraindicated in lactating/pregnant women, and in patients with epilepsy, myasthenia gravis and multiple sclerosis.
Dosage Information
For the treatment of amoebiasis, adult patients should take 1g daily in 2 doses for 7-10 days whereas children should be given 10-25mg/kg once a day for 3 days.
For treatment of amoebic dysentery, adults should take 1.5mg once a day for 3 days whereas children should be given 40mg/kg once per day for 3 days.
The typical Ornidazole dosage for treatment of trichomoniasis in adults is 0.5gm once every 12 hours/1.5gm as a single dose for 5 days. In children, 25mg/kg can be taken as a single dose.
For treatment of Giardiasis in adults, 1-1.5gm should be taken once per day for 2 days and in children, 40mg/kg should be taken for two days.
The dosage requirements for the treatment of bacterial vaginitis is 1.5gm, which is taken once every day or 500mg taken as a daily single dose for 5-7 days.
In the event of a missed dose, supportive and symptomatic treatment should be commenced where the Ornidazole is removed through gastric lavage, induced emesis, application of a carthartic or administration of activated charcoal.
Mechanism of Action
The drug is a nitroimidazole with broad spectrum cidal action against specific types of anaerobic bacteria and protozoa. Ornidazole’s selective toxicity in response to anaerobic microbes entails entry of the drug into the cell through diffusion and reduction of the drug’s nitro group into reactive nitro by redox proteins in anaerobic organisms. This activity influences cytotoxic action by destroying DNA and other fundamental molecules. The final step entails destabilization of the DNA helix and the breakage of certain strands.
Drug Interactions
Some medications have a higher probability of interacting with other prescription drugs hence the doctor should approve any medication adjustments. It is essential for a patient to notify their doctor of any medication, herbal treatments and vitamin supplements that they may be taking before the administration of Ornidazole. A prompt notification may minimize the probability of occurrence of specific side effects.
Ornidazole may interact with warfarin and vecuronium.
Warnings
It is recommended that a patient abstains from alcohol intake for at least 3 days after initiation of therapy with this drug. Alcohol use or associated products may influence disulfiram-like responses in some people.
Ornidazole use in pregnant/breastfeeding women is not recommended as the potential risks may outweigh the benefits in some cases. However, a patient should always consult their healthcare practitioner before taking this medication.
The use of Ornidazole may result in drowsiness hence a patient should avoid activities such as the operation of heavy machinery and driving during the first stages of treatment with this drug.
Caution should be taken amongst patients with multiple sclerosis as it is a neurodegenerative disorder associated with the brain. Ornidazole should not be prescribed for patients with convulsion disorders such as epilepsy.
For patients with hepatic/renal impairment, the drug should be used cautiously as it may intensify the severity of the pre-existing condition. In this case, it is recommended that the patient is monitored frequently by their doctor for mild to moderate impairment and the respective dose modifications.
Pharmacokinetics
Ornidazole is absorbed well orally, and it is widely distributed through the body. The drug undergoes metabolism in the liver and part of the drug is excreted in bile whereas the rest is eliminated in urine. The duration of action of the drug is 14 hours.
Side Effects
In the administration of medications to treat specific medical conditions, there is a high probability that unintended side effects will develop. Patients on Ornidazole treatment may experience some of the associated side effects in varying intensities. However, if the symptoms persist for an extended period, the patient should contact their doctor.
Potential side effects may include hormonal imbalances in the thyroid gland, skin rash, urticaria, abdominal distress, vertigo metallic taste, dry mouth, upset stomach, drowsiness, headache and nausea.
Description
Ornidazole is an orally bioavailable 5-nitroimidazole derivative with antibacterial and antiprotozoal activities. Ornidazole inhibits the growth of clinical isolates of
B. fragilis (MICs = 0.5-5 μM) and various anaerobic bacteria when used at concentrations ranging from less than 0.1 to 3.2 μg/ml. It also inhibits the growth of
Giardia isolates (IC
50s = 0.01-0.47 μg/ml). Oral administration of ornidazole reduces
T. vaginalis and
T. foetus infection in mice and
E. histolytica infection in rats with curative dose (CD
50) values of 37, 3, and 10 mg/kg, respectively. Ornidazole (400 mg/kg per day) induces infertility in male rats within 7 days and inhibits spermatozoa binding to rat oocyte zona pellucida.
Chemical Properties
Crystalline Solid
Originator
Tiberal,Roche,W. Germany ,1977
Uses
Ornidazole is a drug that cures some protozoan infections. It has been investigated for use in Crohn's disease after bowel resection. It is indicated in treatment of mixed amoebiasis, mixed amoebic dysentery, mixed giardiasis, trichomoniasis, bacterial vaginosis, Sexually transmitted diseases, infections of gynaecology, lower respiratory tract infections, ENT, surgical and dental infections.
Definition
ChEBI: A C-nitro compound that is 5-nitroimidazole in which the hydrogens at positions 1 and 2 are replaced by 3-chloro-2-hydroxypropyl and methyl groups, respectively. It is used in the treatment of susceptible protozoal infections and for the
treatment of anaerobic bacterial infections.
Manufacturing Process
5g of 1-(2,3-epoxypropyl)-2-methyl-5-nitroimidazole was added to 30 ml of concentrated aqueous hydrochloric acid. The solution was heated to the boiling point for 20 minutes, chilled, diluted with 30 ml of water and carefully neutralized with ammonia to a pH of 7 to 8. It was then saturated with ammonium sulfate. The precipitated oil crystallized after several days. Recrystallized from toluene, there was obtained the 1-(3-chloro-2hydroxypropyl)-2-methyl-5-nitroimidazole product melting at 77°C to 78°C.
Therapeutic Function
Antiinfective
Pharmaceutical Applications
A 5-nitroimidazole available for oral administration, intravenous infusion and as a vaginal pessary. Its activity closely parallels that of metronidazole and tinidazole.
Peak plasma levels after a single 750 mg or 1.5 g oral dose reach 11 mg/L and 30 mg/L, respectively, within about 2 h. The half-life is 12–14 h. It is well absorbed from the vagina, with peak plasma concentrations of 5 mg/L being reached 12 h after the insertion of a 500 mg vaginal pessary. After a single 1 g intravenous infusion for colorectal surgery, serum levels reached about 24 mg/L after 15 min and about 6 mg/L after 24 h. It has wide tissue distribution, including CSF. Plasma protein binding is 10–15%.
It is metabolized in the liver, mainly to hydroxymethyl derivatives. The plasma clearance rate decreases in hepatic failure because of reduced liver metabolism and decreased biliary elimination. About 60% of an oral dose is recovered in the urine and 20% in the feces. The dosing interval should be doubled in patients with severe hepatic impairment, but it is unnecessary to reduce the dose in patients with impaired renal function. It is removed by hemodialysis.
Toxicity and side effects are similar to those of metronidazole and tinidazole and it has similar clinical uses. It has been shown to be effective for the prevention of recurrence of Crohn’s disease after ileocolonic resection.
Safety Profile
Poison by intravenous route. Moderately toxic by ingestion and intraperitoneal routes. Experimental reproductive effects. Mutation data reported. Whenheated to decomposition it emits very toxic fumes of Clí and NOx.
