Avirax HC Cream 5%+1%

Uses

Aciclovir & Hydrocortisone Cream is used for the early treatment of recurrent herpes labialis (cold sores) to reduce the likelihood of ulcerative cold sores and to shorten the lesion healing time in adults and children (6 years of age and older).

Avirax HC Cream 5%+1% is also used to associated treatment for these conditions: Bell's Palsy, Chickenpox, Cytomegalovirus (CMV) Infection, Encephalitis, Herpes Simplex, Herpes Simplex Infection, Herpes Zoster, Herpes simplex of the oral-labial, Herpes simplex type I reactivation, Recurrent Genital Herpes (RGH), Recurrent Herpes Labialis, VZV re-activation, Acute Genital herpes, Acute Herpes labialis, Acute Herpetic keratitis, Severe Genital herpesAcute 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 Avirax HC Cream 5%+1% works

Acyclovir is becomes acyclovir monophosphate due to the action of viral thymidine kinase. Acyclovir monophosphate is converted to the diphosphate form by guanylate kinase. Acyclovir diphosphate is converted to acyclovir triphosphate by nucleoside diphosphate kinase, pyruvate kinase, creatine kinase, phosphoglycerate kinase, succinyl-CoA synthetase, phosphoenolpyruvate carboxykinase and adenylosuccinate synthetase. Acyclovir triphosphate has higher affinity for viral DNA polymerase than cellular DNA polymerase and incorporates into the DNA where the missing 2' and 3' carbons causes DNA chain termination. In other cases acyclovir triphosphate competes so strongly for viral DNA polymerase that other bases cannot associate with the enzyme, inactivating it.

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

Avirax HC Cream 5%+1% dosage

The cream should be topically applied 5 times per day for 5 days. Therapy should be initiated as early as possible after the first signs and symptoms.

It is recommended that Acyclovir IV Injection for Intravenous Infusion should be administered for five to seven days in the treatment of most infections and for at least ten days in the treatment of Herpes simplex encephalitis.

Each 250 mg vial of Acyclovir IV Injection should be reconstituted by the addition of 10 ml of either Water for Injection or Sodium Chloride Intravenous Infusion (0.9% w/v). This provides a solution containing 25 mg Acyclovir per ml.

Each 500 mg vial of Acyclovir IV Injection should be reconstituted by the addition of 10 ml of either Water for Injection or Sodium Chloride Intravenous Infusion (0.9% w/v). This provides a solution containing 50 mg Acyclovir per ml.

Side Effects

The following most common adverse reactions (<1%) were local skin reactions like drying or flaking of the skin; burning or tingling, erythema; pigmentation changes, application site reactions including signs and symptoms of inflammation.

Toxicity

Symptoms of overdose include agitation, coma, seizures, lethargy, and precipitation in renal tubules. These symptoms are more common in patients given high doses without monitoring of fluid and electrolyte balance or reduced kidney function. In the case of an overdose, treat with symptomatic and supportive care.

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

Aciclovir and Hydrocortisone should not be used in the eye, inside the mouth or nose, or on the genitals. Patients should seek medical advice when a cold sore fails to heal within 2 weeks.

Interaction

Concomitant administration of probenecid and acyclovir has reportedly increased the mean plasma half-life and decreased urinary excretion and renal clearance of acyclovir. Amphotericin B has been shown to potentiate the antiviral effect of acyclovir against pseudorabies virus in vitro when both drugs are added to the culture medium. Ketoconazole and acyclovir have shown dose-dependent, synergistic, antiviral activity against herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) in in-vitro replication studies.

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

The volume of distribution of acyclovir is 0.6L/kg.

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

Elimination Route

The oral bioavailability of acyclovir is 10-20% but decreases with increasing doses. Acyclovir ointment is 12 Acyclovir buccal tablets and ophthalmic ointment are minimally absorbed. The bioavailability of acyclovir is not affected by food.

Acyclovir has a mean T_max of 1.1±0.4 hours, mean C_max of 593.7-656.5ng/mL, and mean AUC of 2956.6-3102.5h*ng/mL.

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

The clearance of acyclovir varies from 2.5-3 hours depending on the creatinine clearance of the patient. The plasma half life of acyclovir during hemodialysis is approximately 5 hours. The mean half life in patients from 7 months to 7 years old is 2.6 hours.

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 acyclovir is 248mL/min/1.73m. The total clearance in neonates if 105-122mL/min/1.73m

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

The majority of acyclovir is excreted in the urine as unchanged drug. 90-92% of the drug can be excreted unchanged through glomerular filtration and tubular secretion. 2.

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

Pregnancy & Breastfeeding use

Pregnancy Category B. There are no adequate and well-controlled studies of systemic Aciclovir in pregnant women. No studies have been performed in pregnant women. Systemic exposure of Aciclovir and Hydrocortisone following topical administration of this cream is minimal.

It is not known whether topically applied Aciclovir or Hydrocortisone is excreted in breast milk. Because many drugs are excreted in human milk, caution should be exercised when administered to a nursing woman.

Contraindication

There is no known contraindication.

Special Warning

Safety and effectiveness in pediatric subjects less than 6 years of age have not been established.

Acute Overdose

Symptoms: Elevations in BUN and serum creatinine, subsequent renal failure, anuria, agitation, coma, lethargy, seizures.

Management: Consider use of haemodialysis until renal function is restored.

Storage Condition

Store at 15°C to 25°C. Protected from light and moisture. Keep the medicine out of the reach of children.

Store at 15-30°C.

Innovators Monograph

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