Genta-hc

Uses

Blepharitis, blepharoconjunctivitis, conjunctivitis, dacryocystitis, keratitis, keratoconjunctivitis, acute meibomianitis, and corneal ulcers caused by susceptible organisms. Otorrhea associated with external otitis, chronic suppurative otitis media or subacute purulent otitis media; or postoperative otorrhea, such as that following fenestration, mastoidectomy or tympanoplasty.

Gentamicin cream is used for the topical treatment of the primary and secondary bacterial infections of the skin caused by the organisms sensitive to Gentamicin. Gentamicin may clear infections that have not responded to other topical antibiotics.

Hydrocortisone is used for the use in the following conditions: Primary or secondary adrenocortical insufficiency, Acute adrenocortical insufficiency, Shock unresponsive to conventional therapy, Congenital adrenal hyperplasia, Hypercalcemia associated with cancer, Nonsuppurative thyroiditis, Rheumatic Disorders, Dermatologic Diseases (Allergic States, Severe seborrheic dermatitis, Severe psoriasis, Pemphigus, Severe erythema multiforme), Control of severe or incapacitating allergic conditions (Bronchial asthma, Contact dermatitis, Atopic dermatitis, Serum sickness, Seasonal or perennial allergic rhinitis, Drug hypersensitivity reactions, Urticarial transfusion reactions, Acute noninfectious laryngeal edema), Ophthalmic Diseases (Herpes zoster ophthalmicus, Iritis, iridocyclitis, Chorioretinitis, Diffuse posterior uveitis and choroiditis, Optic neuritis), Gastrointestinal Diseases, Fulminating or disseminated pulmonary tuberculosis when used concurrently with appropriate antituberculous chemotherapy, Loeffler's syndrome, Aspiration pneumonitis, Hematologic Disorders (Acquired, autoimmune hemolytic anemia, Idiopathic thrombocytopenic purpura in adults, Secondary thrombocytopenia, Erythroblastopenia), Neoplastic Diseases (Leukemias and lymphomas in adults, Acute leukemia of childhood), Edematous States, Acute exacerbations of multiple sclerosis

Genta-hc is also used to associated treatment for these conditions: Bacterial Conjunctivitis, Bacterial Infections, Bacterial Peritonitis, Bacterial dacryocystitis, Blepharoconjunctivitis, Central Nervous System Infections, Conjunctivitis allergic, Corneal infection, Dermatitis infected, Ecthyma, Eczematous dermatitis infected, Folliculitis, Furunculosis, Gram-negative enteric bacilli neonatal sepsis, Impetigo contagious, Inflammation, Keratitis bacterial, Keratoconjunctivitis, Meibomianitis, Meningitis, Bacterial, Ocular Inflammation, Pustular Psoriasis (PP), Pustular acne, Pyoderma Gangrenosum, Seborrheic Dermatitis, Septicemia gram-negative, Skin Infections, Skin Infections, Bacterial, Skin and Subcutaneous Tissue Bacterial Infections, Sycosis barbae, Bacterial blepharitis, Bacterial corneal ulcers, Bacterial dermatoses, Complicated Bacterial Urinary Tract Infections, Complicated Respiratory tract infection bacterial, Corticosteroid-responsive dermatoses, Ocular bacterial infections, Severe Endocarditis enterococcal, Severe Infection Pseudomonas aeruginosa, Severe Staphylococcal infectionAcute Gouty Arthritis, Acute Otitis Externa, Adrenal Insufficiency, Allergic Rhinitis (AR), Allergic corneal marginal ulcers, Anal Fissures, Ankylosing Spondylitis (AS), Anterior Segment Inflammation, Aspiration Pneumonitis, Asthma, Atopic Dermatitis (AD), Berylliosis, Bullous dermatitis herpetiformis, Chorioretinitis, Choroiditis, Congenital Adrenal Hyperplasia (CAH), Congenital Hypoplastic Anemia, Corneal Inflammation, Crohn's Disease (CD), Dermatitis, Dermatitis exfoliative generalised, Dermatitis, Contact, Dermatomyositis, Dermatosis, Drug hypersensitivity reaction, Epicondylitis, Erythroblastopenia, Hemorrhoids, Herpes Labialis, Hypercalcemia of Malignancy, Idiopathic Thrombocytopenic Purpura, Infection of the Fenestration Cavity, Infection of the Mastoidectomy Cavity, Iridocyclitis, Iritis, Itching caused by Hemorrhoids, Itching of the Anus, Leukemia, Acute, Leukemias, Loeffler's syndrome, Lymphomas NEC, Malignant Lymphomas, Mycosis Fungoides (MF), Ophthalmia, Sympathetic, Optic Neuritis, Pain caused by Hemorrhoids, Pemphigus, Post-traumatic Osteoarthritis, Primary adrenocortical insufficiency, Proctitis, Proteinuria, Psoriatic Arthritis, Rectal inflammations NEC, Rheumatic heart disease, unspecified, Rheumatoid Arthritis, Rheumatoid Arthritis, Juvenile, Seasonal Allergic Conjunctivitis, Secondary adrenocortical insufficiency, Secondary thrombocytopenia, Serum Sickness, Severe Seborrheic Dermatitis, Skin Diseases, Stevens-Johnson Syndrome, Synovitis, Systemic Lupus Erythematosus (SLE), Trichinosis, Tuberculous Meningitis, Ulcerative Colitis, Acquired immune hemolytic anemia, Acute Bursitis, Acute Tenosynovitis, Acute rheumatic carditis, Cryptitis, Disseminated Pulmonary Tuberculosis, Fulminating Pulmonary Tuberculosis, Itching skin, Non-suppurative Thyroiditis, Severe Erythema multiforme, Severe Psoriasis, Subacute Bursitis, Superficial infection of the external auditory canal with inflammation, Symptomatic Sarcoidosis, Systemic Dermatomyositis, Varicella-zoster virus acute retinal necrosis, Palliative

How Genta-hc works

There are 3 key phases of aminoglycoside entry into cells. The first “ionic binding phase” occurs when polycationic aminoglycosides bind electrostatically to negatively charged components of bacterial cell membranes including with lipopolysaccharides and phospholipids within the outer membrane of Gram-negative bacteria and to teichoic acids and phospholipids within the cell membrane of Gram-positive bacteria. This binding results in displacement of divalent cations and increased membrane permeability, allowing for aminoglycoside entry. The second “energy-dependent phase I” of aminoglycoside entry into the cytoplasm relies on the proton-motive force and allows a limited amount of aminoglycoside access to its primary intracellular target - the bacterial 30S ribosome. This ultimately results in the mistranslation of proteins and disruption of the cytoplasmic membrane.[A233320] Finally, in the “energy-dependent phase II” stage, concentration-dependent bacterial killing is observed. Aminoglycoside rapidly accumulates in the cell due to the damaged cytoplasmic membrane, and protein mistranslation and synthesis inhibition is amplified. The necessity of oxygen-dependent active transport explains why aminoglycosides are ineffective against anaerobic bacteria. Hence, aminoglycosides have both immediate bactericidal effects through membrane disruption and delayed bactericidal effects through impaired protein synthesis; observed experimental data and mathematical modeling support this two-mechanism model. Inhibition of protein synthesis is a key component of aminoglycoside efficacy. Structural and cell biological studies suggest that aminoglycosides bind to the 16S rRNA in helix 44 (h44), near the A site of the 30S ribosomal subunit, altering interactions between h44 and h45. This binding also displaces two important residues, A1492 and A1493, from h44, mimicking normal conformational changes that occur with successful codon-anticodon pairing in the A site.[A232324, A232329] Overall, aminoglycoside binding has several negative effects including inhibition of translation, initiation, elongation, and ribosome recycling. Recent evidence suggests that the latter effect is due to a cryptic second binding site situated in h69 of the 23S rRNA of the 50S ribosomal subunit.[A232329, A232339] Also, by stabilizing a conformation that mimics correct codon-anticodon pairing, aminoglycosides promote error-prone translation.[A232344] Mistranslated proteins can incorporate into the cell membrane, inducing the damage discussed above.

The short term effects of corticosteroids are decreased vasodilation and permeability of capillaries, as well as decreased leukocyte migration to sites of inflammation.[A187463] Corticosteroids binding to the glucocorticoid receptor mediates changes in gene expression that lead to multiple downstream effects over hours to days.[A187463]

Glucocorticoids inhibit neutrophil apoptosis and demargination; they inhibit phospholipase A2, which decreases the formation of arachidonic acid derivatives; they inhibit NF-Kappa B and other inflammatory transcription factors; they promote anti-inflammatory genes like interleukin-10.[A187463]

Lower doses of corticosteroids provide an anti-inflammatory effect, while higher doses are immunosuppressive.[A187463] High doses of glucocorticoids for an extended period bind to the mineralocorticoid receptor, raising sodium levels and decreasing potassium levels.[A187463]

Dosage

Genta-hc dosage

Eye: 1-2 drops instilled in affected eye up to 6 times a day or more frequently if required (severe infections may require 1-2 drops every 15-20 minutes initially, reducing the frequency of instillation gradually as the infection is controlled).

Ear: The area should be cleaned and 2-3 drops should be instilled every 3-4 times a day and at night, or more frequently if required.

A small amount of Gentamicin should be applied gently to the affected areas three to four times daily. The area treated may be covered with a gauze dressing if desired. Before applying the medication the affected area should be properly cleaned.

Tablet: The initial dosage of Hydrocortisone Tablets may vary from 20 mg to 240 mg of hydrocortisone per day depending on the specific disease entity being treated. In situations of less severity, lower doses will generally suffice, while in selected patients higher initial doses may be required. The initial dosage should be maintained or adjusted until a satisfactory response is noted. If after a reasonable period of time there is a lack of satisfactory clinical response, Hydrocortisone Tablets should be discontinued and the patient transferred to other appropriate therapy.

It should be emphasized that dosage requirements are variable and must be individualized on the basis of the disease under treatment and the response of the patients.After a favorable response is noted, the proper maintenance dosage should be determined by decreasing the initial drug dosage in small decrements at appropriate time intervals until the lowest dosage which will maintain an adequate clinical response. It should be kept in mind that constant monitoring is needed in regard to drug dosage. If, after long-term therapy the drug is to be stopped, it is recommended that it be withdrawn gradually, rather than abruptly.

Injection:

• Adult: By IM injection or slow IV injection or infusion. The initial dose of Hydrocortisone sterile powder is 100 mg to 500 mg, depending on the severity of the condition. This dose may be repeated at intervals of 2, 4 or 6 hours as indicated by the patient's response and clinical condition.
• Children: By slow IV injection, up to 1 year 25 mg, 1-5 years 50 mg, 6-12 years 100 mg.

Side Effects

In patients with dermatoses treated with gentamicin, irritation (erythema and pruritus) had been reported in small number of cases. Itching, redness, swelling or other signs of irritation may develop. With the eye/ear drop bacterial and corneal ulcer have developed during treatment with gentamicin. Most frequently reported adverse reactions are ocular burning and irritation upon drug instillation, non specific conjunctivitis, conjunctival epithelial defects, and conjunctival hyperemia.

Gentamicin cream is well tolerated. There has been no evidence of irritation and sensitization after using Gentamicin cream.

Hydrocortisone is generally well tolerated except in prolonged high doses. It may cause cardiac arrhythmia, esophageal candidiasis, menstrual irregularity, decreased carbohydrate & glucose tolerance, fluid retention, increased appetite, weight gain, euphoria, mood swings, depression, insomnia, acne etc.

Toxicity

As with other aminoglycosides, nephrotoxicity and ototoxicity are associated with gentamicin. Signs of nephrotoxicity include an increase in plasma creatinine and urea, while signs of ototoxicity include issues with balance, nausea, tinnitus, and hearing loss. It is important to note that aminoglycoside-induced nephrotoxicity is typically reversible, while ototoxicity is more likely to be permanent. The risk of both toxicities increases with long-term gentamicin therapy. Gentamicin is considered to be more vestibulotoxic than cochleotoxic compared to other aminoglycosides. Unfortunately, gentamicin-related ototoxicity does not correlate with cumulative dosing, peak and trough levels, or dosing schedule. The unpredictability of ototoxicity supports close monitoring of the patient throughout treatment. In cases of toxicity or overdose, the medication should be discontinued immediately; hemodialysis may be initiated to lower gentamicin serum concentrations.

Data regarding acute overdoses of glucocorticoids are rare. Chronic high doses of glucocorticoids can lead to the development of cataract, glaucoma, hypertension, water retention, hyperlipidemia, peptic ulcer, pancreatitis, myopathy, osteoporosis, mood changes, psychosis, dermal atrophy, allergy, acne, hypertrichosis, immune suppression, decreased resistance to infection, moon face, hyperglycemia, hypocalcemia, hypophosphatemia, metabolic acidosis, growth suppression, and secondary adrenal insufficiency. Overdose may be treated by adjusting the dose or stopping the corticosteroid as well as initiating symptomatic and supportive treatment.

Precaution

If these occurs or if irritation, sensitization develops, treatment with gentamicin should be discontinued and appropriate therapy instituted. Gentamicin ear/eye drops is not for injection. It should never be injected subconjunctivally, nor it should be directly introduced into the anterior chamber of the eye.

Use of topical antibiotics occasionally cause overgrowth of nonsusceptible organisms including fungi. If this occurs or if irritation, sensitisation or super infection develops, treatment with Gentamicin should be discontinued and appropriate therapy should be instituted.

Hydrocortisone should be used with caution in patients with a history of peptic ulceration as it increases the incidence of peptic ulceration. This drug should be used with caution in patients with congestive heart failure, hypertension, glaucoma, diabetic mellitus and epilepsy.

Interaction

None has been reported so far with topical and Eye/Ear drops.

Drug interaction of hydrocortisone has been reported with amphotericin B, potassium-depleting agents, macrolide antibiotics, warfarin, antidiabetics, isoniazid, digitalis glycosides, estrogens, barbiturates, phenytoin, carbamazepine, ketoconazole, aspirin etc.

Volume of Distribution

Total hydrocortisone has a volume of distribution of 39.82L, while the free fraction has a volume of distribution of 474.38L.

Elimination Route

Oral hydrocortisone at a dose of 0.2-0.3mg/kg/day reached a mean C_max of 32.69nmol/L with a mean AUC of 90.63h*nmol/L A 0.4-0.6mg/kg/day dose reached a mean C_max of 70.81nmol/L with a mean AUC of 199.11h*nmol/L. However, the pharmacokinetics of hydrocortisone can vary by 10 times from patient to patient.

Topical hydrocortisone cream is 4-19% bioavailable[8546995] with a T_max of 24h.

Hydrocortisone retention enemas are have a bioavailability of 0.810 for slow absorbers and 0.502 in rapid absorbers. Slow absorbers take up hydrocortisone at a rate of 0.361±0.255/h while fast absorbers take up hydrocortisone at a rate of 1.05±0.255/h.

A 20mg IV dose of hydrocortisone has an AUC of 1163±277ng*h/mL.

Half Life

One study assessing the pharmacokinetics of gentamicin in children and adults reported a mean half-life of 75 minutes after intravenous administration. The mean half-life associated with intramuscular administration was about 29 minutes longer. Fever and anemia may result in a shorter half-life although dose adjustments are not usually necessary. Severe burns are also associated with a shorter half-life and may result in lower gentamicin serum concentrations.

Total hydrocortisone via the oral route has a half life of 2.15h while the free fraction has a half life of 1.39h. A 20mg IV dose of hydrocortisone has a terminal half life of 1.9±0.4h.

Clearance

The renal clearance of gentamicin is comparable to individual creatinine clearance.

Total hydrocortisone by the oral route has a mean clearance of 12.85L/h, while the free fraction has a mean clearance of 235.78L/h. A 20mg IV dose of hydrocortisone has a clearance of 18.2±4.2L/h.

Elimination Route

Gentamicin is excreted primarily by the kidneys. In patients with normal renal function, 70% or more of an initial gentamicin dose can be recovered in the urine within 24 hours. Excretion of gentamicin is significantly reduced in patients with renal impairment.

Corticosteroids are eliminated predominantly in the urine.[A187436] However, data regarding the exact proportion is not readily available.

Pregnancy & Breastfeeding use

Consideration should be given the possibility of foetal ototoxicity when gentamicin is applied topically to large denuded areas of skin. For Gentamicin Eye/Ear Drops safety profile in pregnancy is not yet established and should be administered when considered essential.

Pregnancy category C. Corticosteroids should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Use in nursing mother: Systemically administered corticosteroids appear in human milk and could suppress growth, interfere with endogenous corticosteroid production, or cause other untoward effects. Because of the potential for serious adverse reactions in nursing infants from corticosteroids, a decision should be made whether to continue nursing or discontinue the drug, taking into account the importance of the drug to the mother.

Contraindication

Gentamicin is contraindicated in individuals with a history of sensitivity reaction to any of its components. Use of topical Gentamicin may occasionally allow overgrowth of nonsusceptible organisms, including fungi.

Hydrocortisone is contraindicated in severe systemic fungal infections and patients with known hypersensitivity to any component of this product.

Special Warning

Use in elderly patients: Clinical studies were not done in patients’ aged 65 and above. In general dose selection for an elderly patients should be cautious, usually starting at the low end of the dosing range.

Storage Condition

To avoid contamination, do not touch the tip of the container to the eye, eyelid or any surface.

Store at 15-30°C.

Innovators Monograph

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