Mytrex F

Uses

This medication is a combination antibiotic and steroid used on the skin to treat an infection and relieve associated itching and swelling.

Mytrex F is also used to associated treatment for these conditions: Acne pustular, Allergic Contact Dermatitis, Allergy Skin, Atopic Dermatitis (AD), Atopic Dermatitis (AD) of the external ear canal, Bacterial diarrhoea, Burns, Carbuncle, Cradle Cap, Dermatitis, Dermatitis, Contact, Dermatitis, Eczematous, Diarrhoea, Discoid Lupus Erythematosus (DLE), Ear infection bacterial, Ear infection bacterial caused by susceptible bacteria, Gastrointestinal Infections, Hepatic coma, Hidradenitis Suppurativa (HS), Hot Water Burns (Scalds), Impetigo, Impetigo contagious, Infantile Eczema, Infected Wounds, Infected skin ulcer, Infection of the outer ear caused by susceptible bacteria, Infectious diarrhea, Inflammatory Reaction caused by Acne, Intertrigo, Itching caused by Infection, Lichen Planus (LP), Localized Infection caused by susceptible bacteria, Nail infection, Neurodermatitis, Otitis Externa, Postoperative Wound Infection, Psoriasis Vulgaris (Plaque Psoriasis), Pustular Dermatosis, Radiodermatitis, Secondarily Infected Eczema, Secondary Bacterial Infection, Skin Burns, Skin Infections, Skin Infections, Bacterial, Skin Irritation, Skin Ulcer, Solar erythema, Abrasions, Blistering caused by Staphylococcus, Erythematous eruptions, Intertriginous erythema of the anogenital, Ocular bacterial infections caused by susceptible bacteria, Resistant to other corticosteroids Dermatosis, Susceptible Bacterial InfectionsAnal candidiasis, Candidiasis, Invasive, Intestinal Candidiasis, Mixed Vaginal Infections caused by Trichomonas Vaginalis, candida albicans, Oral Candidiasis, Pruritus Ani, Pruritus Vulvae, Skin candida, Trichomonas Vaginitis, Vaginal Candidiasis, Vulvovaginal Candidiasis, Corticosteroid-responsive dermatoses, Cutaneous candidiasisAcne, Acne Vulgaris, Acute Gouty Arthritis, Allergic Contact Dermatitis, Allergic Rhinitis (AR), Allergy Skin, Alopecia Areata (AA), Ankylosing Spondylitis (AS), Asthma, Atopic Dermatitis (AD), Autoimmune Hemolytic Anemia, Berylliosis, Bullous dermatitis herpetiformis, Chapped skin, Chronic Eczema, Chronic Inflammatory Skin Diseases, Congenital Adrenal Hyperplasia (CAH), Congenital Hypoplastic Anemia, Crohn's Disease (CD), Dental Cavity, Dermatitis, Dermatitis, Contact, Dermatitis, Eczematous, Dermatomyositis, Diaper Rash, Discoid Lupus Erythematosus (DLE), Edema of the cerebrum, Epicondylitis, Erythroderma, Fungal infectious disorders of the Beard, Gingivitis, Hemangiomas, Hemorrhoids, Hypercalcemia, Infected Wound, Infections, Fungal, Inflammation of Mouth, Intertrigo, Itching of the Anus, Itching of the External Genitalia, Itching of the Foot, Itching of the genitals, Itching of the hand, Juvenile Idiopathic Arthritis (JIA), Keloid Scars, Leukemias, Lichen Planus (LP), Lichen simplex chronicus, Malignant Lymphomas, Mycosis Fungoides (MF), Mycotic Eczema, Necrobiosis lipoidica diabeticorum, Neurodermatitis, Nummular Dermatitis, Ocular Inflammation, Ophthalmia, Sympathetic, Oral Erosive Lichen Planus, Oral Infection, Otitis Externa, Pemphigus, Pericarditis, Polymyositis, Post-Herpetic Neuralgia (PHN), Primary adrenocortical insufficiency, Proteinuria, Psoriasis Vulgaris (Plaque Psoriasis), Psoriatic Arthritis, Psoriatic plaque, Pure Red Cell Aplasia, Purulent Wounds, Pyoderma caused by susceptible bacteria, Regional Enteritis, Rheumatoid Arthritis, Ringworm Folliculitis, Seborrheic Dermatitis, Seborrheic Dermatitis, Eczematous, Secondary Impetiginization, Secondary adrenocortical insufficiency, Secondary thrombocytopenia, Serum Sickness, Skin Mycoses, Stomatitis, Aphthous, Stomatitis, Denture, Synovitis, Systemic Lupus Erythematosus (SLE), Temporal Arteritis, Tinea Corporis, Transfusion Reactions, Trichinosis, Tuberculosis (TB), Ulcerative Colitis, Urticaria, Uveitis, Acute Bursitis, Acute Multiple sclerosis, Acute Rheumatic heart disease, unspecified, Acute Tenosynovitis, Corticosteroid-responsive dermatoses, Cutaneous candidiasis, Cystic tumour of the ganglia, Exfoliative erythroderma, Granuloma annulare lesions, Idiopathic eosinophilic pneumonias, Non-suppurative Thyroiditis, Oral infections, Oral lesions, Severe Erythema multiforme, Subacute Dermatitis, Eczematous, Symptomatic Sarcoidosis, Ulceration of the mouth, Ulcerative stomatitis

How Mytrex F works

Like other aminoglycoside antibiotic drugs, neomycin inhibits bacterial ribosomes by binding to the 30S ribosomal subunit of susceptible bacteria and disrupting the translational machinery of bacterial protein synthesis. Bacterial translation is normally initiated by the mRNA binding to the 30S ribosomal subunit and subsequent binding with 50S subunit for elongation.

Nystatin is a channel-forming ionophore, meaning it exerts its therapeutic effect via formation of a membrane-spanning pore in the fungal plasma membrane. The formation of this pore results in a change in membrane permeability that allows for leakage of intracellular contents and the subsequent disruption of electrochemical gradients necessary for proper cell function. Selectivity for fungal cells over mammalian cells is due to nystatin’s greater binding affinity for ergosterol, a key sterol found in fungal cell walls, as opposed to its mammalian counterpart, cholesterol.

Corticosteroids like triamcinolone inhibit phospholipase A2 on cell membranes, preventing the breakdown of lysosomal membranes of leukocytes, which in turn prevent the formation of arachidonic acid, which decrease expression of cyclooxygenase and lipoxygenase, inhibiting synthesis of prostaglandins and leukotrienes. Anti-inflammatory activity occurs via reversal of vascular dilation and reducing permeability, which prevents macrophage and leukocyte migration. Triamcinolone also inhibits nuclear factor kappa-B, which decreases the production of pro-inflammatory signals such as interleukin-6, interleukin-8, and monocyte chemoattractant protein-1.

Dosage

Mytrex F dosage

This medication is for use on the skin only. Wash your hands before using. Avoid getting this product in your eyes or inside the mouth. If this occurs, wipe off the medication and rinse thoroughly with water. Do not use inside the nose unless directed by your doctor.

Clean and dry the affected area as directed. Apply a small amount of medication in a thin layer on the skin and rub in gently, usually 2 to 3 times daily or as directed by your doctor. Wash your hands after use.

Do not bandage, wrap, or cover the treated area unless you are instructed to do so by your doctor. If this medication is applied to the groin area, do not use tight-fitting plastic pants/diapers/garments for incontinence (loss of control of your bladder or bowels). Doing so may increase the absorption of this product through the skin and increase the risk for side effects.

Do not use large amounts of this medication, apply it more often, or use it for a longer time than directed. Your condition may not improve faster, and the risk for side effects may be increased.

Use this medication regularly in order to get the most benefit from it. To help you remember, use it at the same times each day.

Tell your doctor if your condition does not improve or if it worsens after 1 week.

Side Effects

Prolonged use may cause sensitivity reactions, impaired wound healing, thinning of skin, striae, telangiectasia, hirsutism, hypothalamic-pituitary-adrenal axis suppression, Cushing's syndrome.

Toxicity

The oral LD₅₀ of neomycin sulfate in mouse is > 8 g/kg. The subcutaneous LD₅₀ is 200 mg/kg in rat and 190 mg/kg in mouse. The intraperitoneal LD₅₀ in mouse is 305 mg/kg. The oral Lowest published toxic dose (TDLo) in woman is 12600 mg/kg/7D.

Because of low absorption, acute overdosage from oral neomycin is not likely to occur. However, prolonged administration of neomycin should be avoided because of the possibility of some systemic absorption and the risk of neurotoxicity, ototoxicity, and/or nephrotoxicity. Hemodialysis will remove neomycin from the blood. While nephrotoxicity and ototoxicity have been reported in otherwise patients without compromised renal function, the risk for developing these toxicities is increased in patients with renal impairment. Like other aminoglycosides, neomycin may cause fetal harm and total irreversible bilateral congenital deafness when administered in pregnant women.

The oral LD₅₀ in rats is 10 g/kg. There have been no reports of serious toxic effects following overdosage of nystatin - doses in excess of five million units daily have resulted in nausea and gastrointestinal upset with no other associated effects.

The subcutaneous LD₅₀ of triamcinolone acetonide in rats is 13,100µg/kg and in mice is 132mg/kg. The oral LD₅₀ in rats is 1451mg/kg and in mice is 2168mg/kg.[LD₅₀] The intraperitoneal LD₅₀ in mice is 105mg/kg.[LD₅₀]

Patients experiencing an overdose may develop Cushing's syndrome. This overdose may be treated with supportive therapy and mifepristone for its antiglucocorticoid activity.

Precaution

Patients with established hearing loss. Avoid occlusive dressing and prolonged or recurrent use. Avoid contact with eyes or mucous membranes. If there is no clinical improvement after 7 days, discontinue use as the infection may be masked by the steroid. Limit use to 5 days if used on the face or on children <1 yr. Use with caution and sparingly on inflamed or damaged skin (e.g extensive burns, trophic ulceration). Pregnancy.

Interaction

Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor or pharmacist first.

Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of:

• other products for the skin (e.g., corticosteroids/antiseptics)
• aminoglycoside antibiotics (e.g., gentamicin, tobramycin)
• corticosteroids taken by mouth (e.g., prednisone)

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.

Volume of Distribution

The small fraction of absorbed neomycin is rapidly distributed in the tissues. The amount of systemically absorbed neomycin is reported to increase cumulatively with each repeated dose administered until a steady state is reached.

Nystatin is not absorbed into the systemic circulation and thus does not undergo distribution.

The apparent volume of distribution of triamcinolone is 115.2±10L. The mean apparent volume of distribution of triamcinolone acetonide is 1.96L/kg. The apparent volume of distribution of triamcinolone diacetate is 119.7±33.14L.

Elimination Route

Neomycin is poorly absorbed from the gastrointestinal tract. Gastrointestinal absorption of the drug may be increased if inflammatory or ulcerative gastrointestinal disease is present.

Systemic absorption of nystatin is minimal following oral administration, and no detectable plasma concentrations are attained following topical or vaginal administration.

A 16mg oral dose of triamcinolone reaches a C_max of 5.23±0.84ng/mL with a T_max of 2.24±0.78h and an AUC of 36.0±6.2ng*h/mL.

A 2mg intravenous dose of triamcinolone acetonide has an AUC of 57.7ng*h/mL. The bioavailability of 800µg of inhaled triamcinolone acetonide is 25%, with 10.4% coming from pulmonary absorption and the rest being accounted for by deposition on the oral mucosa and other underlying factors. An inhaled dose of triamcinolone acetonide reaches a C_max of 0.92ng/mL with a T_max of 1.74h and an AUC of 5.12ng*h/mL. The fraction of an inhaled dose that is actually absorbed via the pulmonary route reaches a C_max of 0.55ng/mL with a T_max of 0.66h and an AUC of 2.15ng*h/mL.

A 16mg oral dose of triamcinolone diacetate reaches a C_max of 5.33±1.55ng/mL with a T_max of 1.86±0.47h and an AUC of 32.7±9.9ng*h/mL.

Half Life

There is limited information on the half-life of neomycin.

The half life of triamcinolone is 2.7h. The mean terminal elimination half life following an inhaled dose of triamcinolone acetonide is 2.4h. The half life of triamcinolone diacetate is 2.8h.

Clearance

There is limited information on the clearance rate of neomycin.

The clearance of triamcinolone is 28.6±5.6L/h. The mean total body clearance of triamcinolone acetonide is 0.57L/h. The clearance of triamcinolone diacetate is 34.4±10.6L/h.

Elimination Route

The small absorbed fraction of neomycin is excreted by the kidney. The unabsorbed portion of the drug is excreted unchanged in the feces.

The majority of orally administered nystatin is eliminated unchanged in the feces.

Approximately 20% of a dose of triamcinolone is recovered in the urine as the unchanged drug, 25% is recovered as 6-beta-hydroxy-triamcinolone, and 5% is recovered as unidentified metabolites.

Pregnancy & Breastfeeding use

Pregnancy Category- Not Classified. FDA has not yet classified the drug into a specified pregnancy category.

Contraindication

Tuberculous, viral lesions of the skin (e.g. herpes simplex and varicella); fungal lesions not susceptible to nystatin, facial rosacea, acne vulgaris or perioral dermatitis. Not to be applied to the external auditory canal in patients with perforated tympanic membranes. Do not use on extensive areas to reduce risk of systemic absorption and neomycin-induced ototoxicity. Not recommended for <1 yr.

Acute Overdose

Topically applied corticosteroids can be absorbed in sufficient amounts to produce systemic effects e.g., mild, reversible suppression of adrenal function, ecchymoses of the skin, peptic ulceration, hypertension, aggravation of infection, hirsutism, acne, edema and muscle weakness

Storage Condition

Store at room temperature between 15 and 30 degrees C, away from heat. Check the expiration date on the tube and discard any expired medication.

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