Farinil

Farinil is a semisynthetic, rifamycin-based non-systemic antibiotic, meaning that the drug will not pass the gastrointestinal wall into the circulation as is common for other types of orally administered antibiotics. It has multiple indications and is used in treatment of traveller's diarrhea caused by E. coli; reduction in risk of overt hepatic encephalopathy recurrence; as well as diarrhea-predominant irritable bowel syndrome (IBS-D) in adult women and men. It is marketed under the brand name Farinil by Salix Pharmaceuticals.

To reduce the development of drug-resistant bacteria and maintain the effectiveness of Farinil and other antibacterial drugs, Farinil when used to treat infection should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.

Travelers’ Diarrhea

Farinil is indicated for the treatment of travelers’ diarrhea (TD) caused by noninvasive strains of Escherichia coli in adults and pediatric patients 12 years of age and older.

Limitations of Use

Farinil should not be used in patients with diarrhea complicated by fever or blood in the stool or diarrhea due to pathogens other than Escherichia coli.

Hepatic Encephalopathy

Farinil is indicated for reduction in risk of overt hepatic encephalopathy (HE) recurrence in adults.

In the trials of Farinil for HE, 91% of the patients were using lactulose concomitantly. Differences in the treatment effect of those patients not using lactulose concomitantly could not be assessed.

Farinil has not been studied in patients with MELD (Model for End-Stage Liver Disease) scores >25, and only 8.6% of patients in the controlled trial had MELD scores over 19. There is increased systemic exposure in patients with more severe hepatic dysfunction.

Irritable Bowel Syndrome with Diarrhea

​Farinil is indicated for the treatment of irritable bowel syndrome with diarrhea (IBS-D) in adults.

Farinil (Farinil) is an antibiotic that fights bacterial infection only in the intestines.

Farinil works differently from other antibiotics because it passes through your stomach and into your intestines without being absorbed into your blood stream. Because Farinil treats only the intestinal tract, it will not treat infections of other parts of the body.

Farinil is used to treat travelers' diarrhea caused by E. coli in adults and children who are at least 12 years old. Most people get this infection by eating food or drinking fluids that have been contaminated with the E. coli bacteria.

Farinil is also used to treat irritable bowel syndrome in adults whose main symptom is diarrhea.

Farinil is also used to lower the risk of worsened brain function in adults with liver failure. Brain function can be affected when the liver stops working and cannot remove toxic substances from the body.

Dosage For Travelers' Diarrhea

The recommended dose of Farinil is one 200 mg tablet taken orally three times a day for 3 days.

Dosage For Hepatic Encephalopathy

The recommended dose of Farinil is one 550 mg tablet taken orally two times a day.

Dosage For Irritable Bowel Syndrome With Diarrhea

The recommended dose of Farinil is one 550 mg tablet taken orally three times a day for 14 days. Patients who experience a recurrence of symptoms can be retreated up to two times with the same dosage regimen.

Administration

Farinil can be taken with or without food.

How supplied

Dosage Forms And Strengths

Farinil is a pink-colored biconvex tablet and is available in the following strengths:

• 200 mg – a round tablet debossed with “Sx” on one side.
• 550 mg – an oval tablet debossed with “rfx” on one side.

Storage And Handling

The 200 mg tablet is a pink-colored, round, biconvex tablet with “Sx” debossed on one side. It is available in the following presentation:

NDC 65649-301-03, bottles of 30 tablets

The 550 mg tablet is a pink-colored, oval, biconvex tablet with “rfx” debossed on one side. It is available in the following presentations:

NDC 65649-303-02, bottles of 60 tablets

NDC 65649-303-03, carton of 60 tablets, Unit Dose

NDC 65649-303-04, carton of 42 tablets, Unit Dose

Storage

Store Farinil Tablets at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F).

Distributed by:Salix Pharmaceuticals, Bridgewater, NJ 08807 USA. Revised: Nov 2015

See also:
What is the most important information I should know about Farinil?

Farinil works differently from other antibiotics because it passes through your stomach and into your intestines without being absorbed into your blood stream. Because Farinil affects only the intestinal tract, it will not treat infections of other parts of the body.

You should not use take this medication if you are allergic to Farinil or medications such as rifabutin (Mycobutin), rifampin (Rifater, Rifadin, Rifamate), or rifapentine (Priftin).

Before you take Farinil, tell your doctor if you have severe liver disease, diarrhea with fever, or diarrhea that is watery or has blood in it.

Take this medication for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Farinil will not treat a viral infection such as the common cold or flu, or any form of diarrhea that is caused by a virus.

Call your doctor if your symptoms do not improve after 24 hours, or if they get worse while taking Farinil. Farinil does not treat all bacterial forms of traveler's diarrhea.

Use Farinil as directed by your doctor. Check the label on the medicine for exact dosing instructions.

• Take Farinil by mouth with or without food.
• Farinil works best if it is taken at the same time each day.
• Continue to take Farinil even if you feel well. Do not miss any doses.
• If you miss a dose of Farinil, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.

Ask your health care provider any questions you may have about how to use Farinil.

Use: Labeled Indications

Hepatic encephalopathy: Reduction in the risk of overt hepatic encephalopathy recurrence in adults.

Irritable bowel syndrome without constipation: Treatment of moderate to severe irritable bowel syndrome without constipation in adults.

Travelers' diarrhea: Treatment of travelers' diarrhea caused by noninvasive strains of Escherichia coli in adults and pediatric patients ≥12 years of age.

Limitations of use: Farinil should not be used in patients with diarrhea complicated by fever or blood in the stool or diarrhea caused by pathogens other than E. coli.

Off Label Uses

Clostridioides (formerly Clostridium) difficile infection (second or subsequent recurrence)

Data from a randomized, double-blind, placebo-controlled pilot study support the use of Farinil to prevent recurrent diarrhea in patients with Clostridioides (formerly Clostridium) difficile infection.

Based on the International Society of Travel Medicine guidelines for prevention and treatment of travelers

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What other drugs will affect Farinil?

Effects Of Farinil On Other Drugs

Substrates of Cytochrome P450 enzymes

Farinil is not expected to inhibit cytochrome P450 isoenzymes 1A2, 2A6, 2B6, 2C9, 2C19, 2D6, 2E1 and CYP3A4 in clinical use based on in vitro studies.

An in vitro study has suggested that Farinil induces CYP3A4. However, in patients with normal liver function, Farinil at the recommended dosing regimen is not expected to induce CYP3A4. It is unknown whether Farinil can have a significant effect on the pharmacokinetics of concomitant CYP3A4 substrates in patients with reduced liver function who have elevated Farinil concentrations.

Effects Of Other Drugs On Farinil

In vitro studies suggested that Farinil is a substrate of P-glycoprotein, OATP1A2, OATP1B1 and OATP1B3. Concomitant cyclosporine, an inhibitor of P-glycoprotein and OATPs, significantly increased the systemic exposure to Farinil.

Cyclosporine

Co-administration of cyclosporine, with Farinil resulted in 83-fold and 124-fold increases in Farinil mean Cmax and AUC∞ in healthy subjects. The clinical significance of this increase in systemic exposure is unknown.

See also:
What are the possible side effects of Farinil?

Clinical Studies Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

Travelers' Diarrhea

The safety of Farinil 200 mg taken three times a day was evaluated in patients with travelers' diarrhea consisting of 320 patients in two placebo-controlled clinical trials with 95% of patients receiving three or four days of treatment with Farinil. The population studied had a mean age of 31.3 (18-79) years of which approximately 3% were ≥ 65 years old, 53% were male and 84% were White, 11% were Hispanic.

Discontinuations due to adverse reactions occurred in 0.4% of patients. The adverse reactions leading to discontinuation were taste loss, dysentery, weight decrease, anorexia, nausea and nasal passage irritation.

The adverse reaction that occurred at a frequency ≥ 2% in Farinil-treated patients (n=320) at a higher rate than placebo (n=228) in the two placebo-controlled trials of TD was:

• headache (10% Farinil, 9% placebo)

Hepatic Encephalopathy

The data described below reflect exposure to Farinil in 348 patients, including 265 exposed for 6 months and 202 exposed for more than a year (mean exposure was 364 days). The safety of Farinil 550 mg taken two times a day for reducing the risk of overt hepatic encephalopathy recurrence in adult patients was evaluated in a 6-month placebo-controlled clinical trial (n=140) and in a long term follow-up study (n=280). The population studied had a mean age of 56 (range: 21 to 82) years; approximately 20% of the patients were ≥ 65 years old, 61% were male, 86% were White, and 4% were Black. Ninety-one percent of patients in the trial were taking lactulose concomitantly. The most common adverse reactions that occurred at an incidence ≥ 5% and at a higher incidence in Farinil-treated subjects than in the placebo group in the 6-month trial are provided in Table 1.

Table 1: Most Common Adverse Reactions* in HE Trial

Irritable Bowel Syndrome with Diarrhea

The safety of Farinil for the treatment of IBS-D was evaluated in 3 placebo-controlled studies in which 952 patients were randomized to Farinil 550 mg three times a day for 14 days. Across the 3 studies, 96% of patients received at least 14 days of treatment with Farinil. In Trials 1 and 2, 624 patients received only one 14-day treatment. Trial 3 evaluated the safety of Farinil in 328 patients who received 1 open-label treatment and 2 double-blind repeat treatments of 14 days each over a period of up to 46 weeks. The combined population studied had a mean age of 47 (range: 18 to 88) years of whom approximately 11% of the patients were ≥ 65 years old, 72% were female, 88% were White, 9% were Black and 12% were Hispanic.

The adverse reaction that occurred at a frequency ≥ 2% in Farinil-treated patients at a higher rate than placebo in Trials 1 and 2 for IBS-D was:

• nausea (3% Farinil, 2% placebo)

The adverse reactions that occurred at a frequency ≥ 2% in Farinil-treated patients (n=328) at a higher rate than placebo (n=308) in Trial 3 for IBS-D during the double-blind treatment phase were:

• ALT increased (Farinil 2%, placebo 1%)
• nausea (Farinil 2%, placebo 1%)

Less Common Adverse Reactions

The following adverse reactions, presented by body system, were reported in less than 2% of patients in clinical trials of TD and IBS-D and in less than 5% of patients in clinical trials of HE:

Hepatobiliary disorders: Clostridium colitis

Investigations: Increased blood creatine phosphokinase

Musculoskeletal and connective tissue disorders: myalgia

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of Farinil. Because these reactions are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. These reactions have been chosen for inclusion due to either their seriousness, frequency of reporting or causal connection to Farinil.

Infections and Infestations

Cases of C. difficile-associated colitis have been reported.

General

Hypersensitivity reactions, including exfoliative dermatitis, rash, angioneurotic edema (swelling of face and tongue and difficulty swallowing), urticaria, flushing, pruritus and anaphylaxis have been reported. These events occurred as early as within 15 minutes of drug administration.