Itrogen Tr
Itrogen Tr Uses, Dosage, Side Effects, Food Interaction and all others data.
Itraconazole is an orally active triazole antifungal drug that has demonstrated a broad spectrum of activity and favorable pharmacokinetic profile. Itraconazole inhibits Cytochrome P-450 dependent enzymes resulting in impairment of the biosynthesis of ergosterol, a major component of the cell membrane of yeast and fungal cells. Being integral to the proper functioning of the cell membrane, inhibition of the synthesis of ergosterol leads to a cascade of abnormalities in permeability, membrane bound enzyme activity, and co-ordination of chitin synthesis leading to inhibition of growth, abnormal cell wall formation and accumulation of intracellular lipids and membranous vesicles.
Itraconazole is an imidazole/triazole type antifungal agent. Itraconazole is a highly selective inhibitor of fungal cytochrome P-450 sterol C-14 α-demethylation via the inhibition of the enzyme cytochrome P450 14α-demethylase. This enzyme converts lanosterol to ergosterol, and is required in fungal cell wall synthesis. The subsequent loss of normal sterols correlates with the accumulation of 14 α-methyl sterols in fungi and may be partly responsible for the fungistatic activity of fluconazole. Mammalian cell demethylation is much less sensitive to fluconazole inhibition. Itraconazole exhibits in vitro activity against Cryptococcus neoformans and Candida spp. Fungistatic activity has also been demonstrated in normal and immunocompromised animal models for systemic and intracranial fungal infections due to Cryptococcus neoformans and for systemic infections due to Candida albicans.
Terbinafine is an allylamine with a range of antifungal activity. It is fungicidal against dermatophytes, moulds and certain dimorphic fungi. Terbinafine is either fungicidal or fungistatic against yeasts, depending on the species. Terbinafine interferes with fungal ergosterol biosynthesis by inhibiting squalene epoxidase in the fungal cell membrane at an early stage. This leads to a deficiency in ergosterol and to intracellular accumulation of squalene, resulting in fungal cell death. Terbinafine is highly effective in fungal infections of the skin, hair and nails caused by Trichophyton spp., Microsporum spp. and Epidermophyton floccosum. It is also effective against yeast infections of the skin, principally those caused by the genus candida. Topical terbinafine appears to be effective in pityriasis versicolor due to Pityrosporum arbiculare.
Terbinafine is an allylamine antifungal that inhibits squalene epoxidase (also known as squalene monooxygenase) to prevent the formation of ergosterol and cause an accumulation of squalene, weakening the cell wall of fungal cells. Terbinafine distributes into tissues and has a long terminal elimination half life, so the duration of action is long. Overdose with terbinafine is rare, even above the therapeutic dose, so the therapeutic index is wide. Patients taking oral terbinafine should have liver function tests performed prior to treatment to reduce the risk of liver injury.
| Trade Name | Itrogen Tr |
| Generic | Terbinafine + Itraconazole |
| Weight | 250mg |
| Type | Tablet |
| Therapeutic Class | |
| Manufacturer | |
| Available Country | India |
| Last Updated: | September 19, 2023 at 7:00 am |
Uses
Itraconazole is used for the treatment of oropharyngeal candidiasis, vulvovaginal candidiasis, pityriasis versicolor, tinea pedis, tinea cruris, tinea corporis, tinea manuum, onychomycosis, histoplasmosis. It is used for the treatment of systemic candidiasis, aspergillosis, and cryptococcosis (including cryptococcal meningitis). It is also used for maintenance therapy in AIDS patients to prevent relapse of underlying fungal infections and in the prevention of fungal infection during prolonged neutropenia.
Terbinafine cream is used for the treatment of the following dermatological infections: interdigital tinea pedis (Athlete’s foot), tinea cruris (jock itch) or tinea corporis (ring worm) due to susceptible organisms and planter tinea pedis (mocasin type) due to Trichophyton spp.
Terbinafine tablet is used for the treatment of onychomycosis of the toe nail or finger nail due to dermatophytes and also by non-dermatophyte fungi.
Itrogen Tr is also used to associated treatment for these conditions: Aspergillosis, Blastomycosis, Chromomycosis, Coccidioidal meningitis, Dermatomycoses, Esophageal Candidiasis, Histoplasmosis, Infections, Fungal, Onychomycosis, Oropharyngeal Candidiasis, Paracoccidioidomycosis, Penicillium marneffei infection, Pulmonary coccidioides, Sporotrichosis, Vulvovaginal Candidiasis, Disseminated Other specified protozoal diseasesOnychomycosis, Pityriasis versicolor, Sporotrichosis, Tinea Capitis, Tinea Corporis, Tinea Cruris, Tinea Pedis, Cutaneous candidiasis, Severe Tinea Corporis, Severe Tinea Cruris, Severe Tinea Pedis
How Itrogen Tr works
Itraconazole interacts with 14-α demethylase, a cytochrome P-450 enzyme necessary to convert lanosterol to ergosterol. As ergosterol is an essential component of the fungal cell membrane, inhibition of its synthesis results in increased cellular permeability causing leakage of cellular contents. Itraconazole may also inhibit endogenous respiration, interact with membrane phospholipids, inhibit the transformation of yeasts to mycelial forms, inhibit purine uptake, and impair triglyceride and/or phospholipid biosynthesis.
Terbinafine inhibits the enzyme squalene monooxygenase (also called squalene epoxidase), preventing the conversion of squalene to 2,3-oxydosqualene, a step in the synthesis of ergosterol. This inhibition leads to decreased ergosterol, which would normally be incorporated into the cell wall, and accumulation of squalene.
Generation of a large number of squalene containing vesicles in the cytoplasm may leach other lipids away from, and further weaken, the cell wall.
Dosage
Itrogen Tr dosage
Oropharyngeal candidiasis: 100 mg daily (200 mg daily in AIDS or neutropenia) for 15 days.
Vulvovaginal candidiasis: 200 mg twice daily for 1 day.
Pityriasis versicolor: 200 mg daily for 7 days.
Tinea corporis and tinea cruris: either 100 mg daily for 15 days or 200 mg daily for 7 days.
Tinea pedis and tinea manuum: either 100 mg daily for 30 days or 200 mg twice daily for 7 days.
Onychomycosis: either 200 mg daily for 3 months or course (pulse) of 200 mg twice daily for 7 days, subsequent courses repeated after 21 days interval. Fingernails two courses, toenails three courses.
Systemic infections (aspergillosis, candidiasis and cryptococcosis including cryptococcal meningitis) where other antifungal drugs inappropriate or ineffective: 200 mg once daily, increased in invasive or disseminated disease and in cryptococcal meningitis to 200 mg twice daily.
Histoplasmosis: 200 mg 1-2 times daily.
Maintenance in AIDS patients to prevent relapse of underlying fungal infection and prophylaxis in neutropenia when standard therapy is inappropriate: 200 mg once daily, increased to 200 mg twice daily if low plasma Itraconazole concentration is detected. Child dose: the recommended dose is 3 to 5 mg/kg/day.
Topical application:
Terbinafine cream to affected areas once or twice daily for 1-2 weeks may be adequate for fungal infections of the skin but certain infections may require oral Terbinafine tablet therapy.Usual duration of treatment of Terbinafine cream:
- In Tinea corporis and Tinea cruris: 1-2 weeks.
- In Tinea pedis: 2-4 weeks (One week of treatment will normally suffice if the cream is applied twice daily.).
- In Cutaneous candidiasis: 1-2 weeks
- In Pityriasis (tinea) versicolor: 2 weeks.
To prevent relapses in fungal infection, treatment should be continued for a adequate length of time. To apply Terbinafine cream clean and dry the affected areas thoroughly and apply the cream once or twice a day to the affected skin and surrounding area in a thin layer and rub in lightly. In the case of intertriginous infections the application may be covered with a gauze strip, especially at night.
Oral administration:
Terbinafine tablet is essential for hair or nail infections:
- The usual oral dose: Terbinafine 250 mg daily for 2 to 12 weeks depending upon the infection.
- Finger nail onychomycosis: Terbinafine 250 mg once daily for 6 weeks.
- Toe nail onychomycosis: Terbinafine 250 mg once daily for 12 weeks.
Should be taken with food. Take immediately after a full meal.
Side Effects
Nausea, abdominal pain, dyspepsia, constipation, headache, dizziness, raised liver enzymes, menstrual disorders, allergic reactions (including pruritus, rash, urticaria and angioedema), hepatitis and cholestatic jaundice, peripheral neuropathy and Stevens-Johnson syndrome reported. On prolonged use hypokalaemia, oedema and hair loss reported.
Terbinafine Tablet: Abdominal discomfort, anorexia, nausea, diarrhoea, headache, rash and urticaria occasionally with arthralgia or myalgia. Less frequently taste disturbance. Rarely liver toxicity, photosensitivity, serious skin reactions etc.
Terbinafine Cream: Redness, itching, or stinging; rarely allergic reactions.
Toxicity
No significant lethality was observed when itraconazole was administered orally to mice and rats at dosage levels of 320 mg/kg or to dogs at 200 mg/kg.
The subcutaneous LD50 in rats and mice is >2g/kg. The TDLO for women is 210mg/kg/6W.
Overdose data with terbinafine is rare, however symptoms are expected to be nausea, vomiting, abdominal pain, dizziness, rash, frequent urination, and headache. Treat overdose with activated charcoal as well as symptomatic and supportive therapy.
Precaution
Absorption is impaired when gastric acidity is reduced. In patients receiving acid neutralizing medicines (e.g. aluminium hydroxide), these should be administered at least 2 hours after the intake of Itraconazole. The drug should be administered after a full meal. Rarely, cases of hepatitis and jaundice have been reported mainly in patients treated for longer than one month. It is therefore, advised to monitor liver function in patients receiving continuous treatment of more than one month.
Terbifine cream is for external use only. Contact with eyes should be avoided.Good general hygiene is necessary in conjunction with the use of Terbinafine in order to prevent reinfection (eg. from underwear, socks,shoes etc).
Terbinafine tablet is not recommended for patients with chronic or active liver disease. Before prescribing terbinafine, pre-existing liver disease should be assessed. Hepatotoxicity may occur in patients with and without pre-existing liver disease. Pretreatment serum transaminase (ALT and AST) tests are advised for all patients before taking terbinafine tablets.
Interaction
The drugs like terfenadine, astemizole, cisapride, HMG-CoA reductase inhibitors such as simvastatin, oral midazolam or triazolam should not be given concurrently with Itraconazole. Significant interactions also observed during co-administration of rifampin, phenytoin, phenobarbital, digoxin, and calcium channel blockers.
In vivo studies have shown that terbinafine is an inhibitor of the CYP450 2D6 isozyme. Drugs predominantly metabolized by the CYP450 2D6 isozyme include the following drug classes: tricyclic antidepressants, selective serotonin reuptake inhibitors, beta-blockers, antiarrhythmics class 1C (e.g., flecainide and propafenone) and monoamine oxidase inhibitors Type B. Co-administration of terbinafine should be done with careful monitoring and may require a reduction in dose of the 2D6-metabolized drug.
Volume of Distribution
- 796 ± 185 L
A single 250mg oral dose of terbinafine has a volume of distribution at steady state of 947.5L or 16.6L/kg.
Elimination Route
The absolute oral bioavailability of itraconazole is 55%, and is maximal when taken with a full meal.
Oral terbinafine is >70% absorbed but only 40% bioavailable after first pass metabolism, reaching a Cmax of 1µg/mL with a Tmax of 2 hours an an AUC of 4.56µg*h/mL. Over the course of a week, 1% topical terbinafine's Cmax increases from 949-1049ng/cm2
Half Life
21 hours
Oral terbinafine has an effective half life of approximately 36 hours. However, the terminal half life ranges from 200-400 hours as it distributes into skin and adipose tissue. 1% topical terbinafine's half life increases over the first seven days from approximately 10-40 hours.
Clearance
- 381 +/- 95 mL/minute [IV administration]
A single 250mg oral dose of terbinafine has a clearance of 76L/h or 1.11L/h/kg.
Elimination Route
Itraconazole is metabolized predominately by the cytochrome P450 3A4 isoenzyme system (CYP3A4) in the liver, resulting in the formation of several metabolites, including hydroxyitraconazole, the major metabolite. Fecal excretion of the parent drug varies between 3-18% of the dose. Renal excretion of the parent drug is less than 0.03% of the dose. About 40% of the dose is excreted as inactive metabolites in the urine. No single excreted metabolite represents more than 5% of a dose.
Terbinafine is approximately 80% eliminated in urine, while the remainder is eliminated in feces. The unmetabolized parent drug is not present in urine.
Pregnancy & Breastfeeding use
Itraconazole is contraindicated in pregnancy. Breast feeding while receiving Itraconazole is not recommended.
Terbinafine tablet: There are no adequate and well controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, and because treatment of onychomycosis can be postponed until after pregnancy is completed, it is recommended that terbinafine not be initiated during pregnancy. After oral administration, terbinafine is present in breast milk of nursing mothers. Treatment with terbinafine in not recommended in nursing mothers.
Terbinafine cream: Foetal toxicity and fertility studies in animals suggest no adverse effects. There is no clinical experience with terbinafine in pregnant women; therefore, unless the potential benefits outweigh any potential risk, terbinafine should not be administered. Terbinafine is excreted in breast milk and therefore mothers should not receive terbinafine treatment whilst breast-feeding.
Contraindication
Itraconazole is contraindicated in patients with known hypersensitivity to the drug or any ingredient in the formulation. Patients who have severe hepatic disease are not advised to take Itraconazole. It is not advisable to use the drug in patients taking rifampin, which appears to initially inhibit and then enhance the metabolism of Itraconazole.
Hypersensitivity to Terbinafine or any of the excipients in thepreparation
Special Warning
Renal Impairment Intravenous: Severe: Contraindicated.
Use in Children: Terbinafine cream appears to be an effective and well-tolerated treatmenr of tinea corposis and tinea cruris in children.
Use in Elderly: Terbinafine appears to be safe in the elderly. The dose should be reduced by half if significant hepatic or renal impairment is present.
Acute Overdose
Symptoms: Same with adverse reactions.
Management: Supportive treatment. May admin activated charcoal if necessary.
Clinical experience regarding overdose with terbinafine tablets is limited. Doses up to 5 grams (20 times the therapeutic daily dose) have been taken without inducing serious adverse reactions. The symptoms of overdose included nausea, vomiting, abdominal pain, dizziness, rash, frequent urination, and headache.
Storage Condition
Protect from light. Store in a cool and dry place. Store between 15˚C and 30˚C.
Store in a cool and dry place, protected from light.
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