Otofa
Otofa Uses, Dosage, Side Effects, Food Interaction and all others data.
Otofa is the prime member of the rifamycin family which are represented by drugs that are a product of fermentation from the gram-positive bacterium Amycolatopsis mediterranei, also known as Streptomyces mediterranei. The parent compound of rifamycin was rifamycin B which was originally obtained as a main product in the presence of diethylbarburitic acid. Some small modifications where performed in this inactive compound and with the creation of rifamycin SV there was the first antibiotic used intravenously for the treatment of tuberculosis.
Otofa has had several direct derivative products such as rifamycin SV, rifaximin, rifampin and rifamycin CV. All of the derivatives have slight different physicochemical properties when compared to the parent structure.
Otofa was further developed by Cosmo Technologies Ltd and approved in November 16, 2018 by the FDA as a prescription drug after being granted the designation of Qualified Infectious Disease Product which allowed it to have a status a priority review. This drug was also sent for review to the EMA in 2015 by Dr. Falk Pharma Gmbh and it was granted a waiver for the tested conditions.
| Trade Name | Otofa |
| Availability | Prescription only |
| Generic | Rifamycin |
| Rifamycin Other Names | Rifamicina, Rifamicine SV, Rifamycin, Rifamycin SV, Rifamycine, Rifamycinum, Rifomycin SV |
| Related Drugs | ciprofloxacin, sulfamethoxazole / trimethoprim, Bactrim, loperamide, Imodium |
| Type | |
| Formula | C37H47NO12 |
| Weight | Average: 697.778 Monoisotopic: 697.309825957 |
| Protein binding | The protein binding of rifamycin is of about 80-95%. |
| Groups | Approved, Investigational |
| Therapeutic Class | |
| Manufacturer | |
| Available Country | Switzerland |
| Last Updated: | September 19, 2023 at 7:00 am |
Uses
Otofa is an antibacterial used to treat traveler's diarrhea.
Otofa is indicated for the treatment of adult patients with travelers' diarrhea caused by noninvasive strains of E. coli. The status of the disease should not be complicated by fever or blood in the stool. To prevent drug-resistant bacteria, it is important to mention that the use of rifamycin for this indication should be only done in cases where the infection is proven or strongly suspected to be caused by bacteria.
Travallers' diarrhea is very common problem affecting 20-60% of the travellers and it is defined as an increase in frequency of bowel movements to three or more loose stools per day during a trip abroad. This condition is rarely life threatening but in severe cases it can produce dehydration and sepsis. The most common cause of travellers' diarrhea is a pathogen and from the pathogens identified, bacteria is the most common cause followed by norovirus, rotavirus and similar viruses.
Otofa is also used to associated treatment for these conditions: Not complicated by fever, not complicated by bloody stool Traveler's Diarrhea caused by noninvasive strains of Escherichia coli, Susceptible Bacterial Infections
How Otofa works
Otofas, as well as all the other members of this group, present an antibacterial mechanism of action related to the inhibition of RNA synthesis. This mechanism of action is done by the strong binding to the DNA-dependent RNA polymerase of prokaryotes. The inhibition of the RNA synthesis is thought to be related with the initiation phase of the process and to involve stacking interactions between the naphthalene ring and the aromatic moiety in the polymerase. As well, it has been suggested that the presence of zinc atoms in the polymerase allows for the binding of phenolic -OH groups of the naphthalene ring.
In eukaryotic cells, the binding is significantly reduced making them at least 100 to 10,000 times less sensitive to the action of rifamycins. The members of the rifamycin family present the same mechanism of action and the structural modifications are usually related to pharmacokinetic properties as well as to the interaction with eukaryotic cells.
Toxicity
In safety studies with rifamycin, it was reported a potential of hepatotoxicity due to the depletion of glutathione and the generation of reactive oxygen species in liver microsomes. It is important to mention that this effect is mainly observed in the intravenous administration as the oral dosage does not have a significant systemic absorption.
Otofa is not genotoxic in bacterial mutation assays, mouse cell mutation assay or mouse bone marrow micronucleus assay. There is no current information about the effects on fertility, overdosage or carcinogenesis.
Food Interaction
- Avoid alcohol.
- Take with a full glass of water.
- Take with or without food.
Otofa Disease Interaction
Major: colitisModerate: diarrhea, hepatic dysfunction, renal impairment
Volume of Distribution
The reported volume of distribution after measured after a dosage of 250 mg of rifamycin is 101.8 L.
Elimination Route
Otofa has a very poor absorption and thus, the generation of an oral modified-release formulation using the technology of the multi-matrix structure was required for the generation of the FDA approved product. This preparation allows the delivery of the active ingredient in the distal small bowel and colon without interfering with the flora in the upper gastrointestinal tract.
The multi-matrix is made by a lipophiic matrix surrounded in a hydrophilic matrix which allows for the protection of the active ingredient from dissolution in the intestinal aqueous fluids before it arrives in the cecum. All this matrix is surrounded by a gastro-resistant polymer that only desintegrate in a pH lower than 7.
All this administration-customed formulation allows for a bioavailability of 6
The reported Cmax, tmax, AUC and mean residence time after a dosage of 250 mg of rifamycin is 36 mg/L, 5 min, 11.84 mg.h/L and 0.49 h respectively.
Half Life
The reported half-life when a dose of 250 mg of rifamycin was administered is 3 h.
Clearance
The reported clearance when a dose of 250 mg of rifamycin was administered is 23.3 L/h.
Elimination Route
From the administered dose, 18%, 50% and 21% is recovered in feces during the first 24, 48 and 72h after administration. This will represent about 90% of the administered dose eliminated by the feces while the urinary secretion is negligible.
Innovators Monograph
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