Tenvir EM (Tenofovir Disoproxil & Emtricitabine)

DESCRIPTION

Tenvir EM is a fixed dose combination two anti-retroviral medications i.e Tenofovir Disoproxil Fumarate & Emtricitabine. Tenvir EM is belongs to combination of two nucleoside reverse transcriptase inhibitor.

Tenvir EM is stops the reverse transcriptase enzyme that is required for viral proliferation. Tenvir EM is not a curable drugs, but it can reduce the disease breakthrough and inhibits the aggravation of HIV-1 infection into AIDS. Tenvir EM is a prescription medication which is used by the patient who is having a valid prescription with the guidance of medical practitioner.

INDICATION

Tenvir EM should be primarily indicated for the treatment of HIV 1 infection condition. Tenvir EM should be applicable for adults & pediatric patients with weight of at least 17kg. Tenvir EM is also indicated for the condition like HIV-1 pre exposure prophylaxis, this may used in concomitant with safer sex practices for prEP to diminish the exposure of sexually acquired HIV-1 infection in adults & pediatrics with weight of at least 35kg. Before starting the Tenvir EM treatment for PrEP condition, patient must be examine for negative HIV-1.

MECHANISM OF ACTION

Tenofovir DF is an acyclic nucleoside phosphonate diester analogue of adenosine monophosphate which is available as prodrug. Emtricitabine is a synthetic nucleoside analogue of cytidine Tenofovir DF experiences diester hydrolysis to shape as Tenofovir and further phosphorylation prompts deliver tenofovir diphosphate. This diphosphate type of tenofovir is denies the movement of HIV-1 RT by battling with deoxyadenosine 5' triphosphate (regular substrate). This may embed into viral DNA causes chain disposal. Emtricitabine undergoes phosphorylation with the help of cellular enzymes to form an active moiety called as Emtricitabine 5’ triphosphate which is responsible for prohibition of HIV-1 RT. This inhibition occurs by fighting active moiety to natural substrate like deoxycytidine 5’ triphosphate get intervened into DNA and causes chain elimination.

PHARMACOKINETIC

ABSORPTION

After absorption of Tenvir EM , reaches maximum plasma concentration time are; Emtricitabine: 1 to 2 hours; tenofovir DF: 1.0 plus or minus 0.4 hour. The oral bioavailability of tenofovir is occurs by 25%, by administering with food, bioavailability reaches by 40%.

DISTRIBUTION

Tenofovir has low binding capacity, <0.7% to human plasma proteins & <7.2% to serum proteins. Emtricitabine has low protein binding capacity by less than 4%.

METABOLISM

The metabolism of Tenofovir DF not induced by cytochrome isoenzymes The metabolism of Emtricitabine is induced by undergoing biotransformation.

ELIMINATION

The elimination of Tenvir EM is occurs through glomerular filteration & active tubular secretion. The half lives of Tenvir EM is Tenofovir DF: 17 hours with range of 12.0 to 25.7 hours. Emtricitabine: 10 hours with range of 7.4 to 18.0 hours

DOSAGE MANAGEMENT

DOSAGE & ADMINISTRATION OF TENVIR EM

1. Before begin the treatment using with Tenvir EM , patient should be examine thoroughly for presence of HBV infection or not. Hepatic function test & renal function test should be monitored. 2. Patients receiving Tenvir EM for PrEP, screening the HIV-1 infection for once three months.

DOSAGE RECOMMENDATION

The advised dose of Tenvir EM for adults & pediatric with weight of at least 35kg is one tablet should be administered as once daily by taking with food or without food.

FOR PREP CONDITION

One Tenvir EM tablet should be taken as once daily for both adults & pediatric with weight of at least 35kg.

DOSAGE ADJUSTMENT FOR RENAL IMPAIRED PATIENTS

CrCl ≥50ml/min, one tablet should be taken for every 24 hours CrCl 30 to 49ml/min, one Tenvir EM tablet should be taken for every 48 hours CrCl <30ml/min, Tenvir EM tablet should not be recommended

WARNING & PRECAUTION

LACTIC ACIDOSIS & HEPATIC STEATOSIS

This fatal condition is occurs due to increased hepatic enzymes. To prevent this condition by monitoring the hepatic functions & hepatic enzymes levels. In severe condition, Tenvir EM should be stopped.

DUE TO DRUG INTERACTIONS

Some combinational therapy leads to cause severe adverse effects. Tenvir EM should not be combined with Trustiva, Atripla, or Viraday.

HIV-1 & HBV CO INFECTION

Due to exposure of advancement of HIV-1 resistance, Tenvir EM should be used in patients who are co infected with HIV-1 HBV by combining with other anti-retroviral drugs. Before initiating the treatment, patient should examined by testing the HIV-1 antibody

AGGRAVATION OF HBV INFECTION

This severe fatal case is occurs, after conclusion of anti-hepatitis B treatment. To prevent this effect by monitoring the patient’s hepatic functions before begin the therapy. In final condition, patient should be resuming with anti-HBV therapy.

BONE DEFECTS

The major risk of Tenvir EM is loss of bone mineral density. To overcome the problem by providing the vitamin D supplements.

NEWLY COMMENCED OR AGGRAVATION OF RENAL IMPAIRED PATIENTS

To prevent this worsening condition, patients renal function should be examine clearly by measuring the creatinine clearance, urine protein, urine glucose levels. Avoid the concomitant use of Tenvir EM with drugs affecting the renal functions.

IMMUNE RECONSTITUTION SYNDROME

This is most frequently occurred in anti-retroviral agents receiving patients. In this condition, Tenvir EM should be discontinued and provide a supportive measures.

LOSS OF VIROLOGICAL RESPONSE

During the combination of triple dose regimens, resistance will produced and leads to loss of activity. Monitoring the patients thoroughly while using triple dose regimen, if resistance formed or not.

SIDE EFFECTS

SIDE EFFECTS OF TENVIR EM
Lactic acidosis & hepatic steatosis Serious exacerbation of HBV Renal damage Immune reconstitution syndrome Bone defects

COMMON EFFECTS

Headache Insomnia Nasopharyngitis Vomiting Fatigue Depression Nausea Diarrhea Respiratory tract infection Sinusitis Rash

LAB ABNORMALITIES

Increased alkaline phosphatase Increased AST & ALT Anemia Increased blood glucose Hematuria Glycosuria Increased cholesterol Elevation of serum lipase Increased creatine kinase Neutropenia

POST MARKETING EFFECTS

Renal & urinary disorders Hepatobiliary disorders Musculoskeletal disorders

CONTRAINDICATIONS

Tenvir EM for PrEP is contraindicated to patients with unidentified or positive HIV-1 satus. Hypersensitivity reactions are formed if patients are contraindicated to component of Tenvir EM .

PREGNANCY & LACTATION

The pregnancy category of Tenvir EM is B Tenvir EM should be used in pregnancy period only after knowing the adverse associated with this drug. Counsel the patients about the risk benefits related to Tenvir EM , before starting the treatment

STORAGE 

Tenvir EM container should be kept at temperature 25°C allowed between 15°C to 30°C Protect away from heat, moisture, & light

MISSED DOSE

Tenvir EM is contains two drugs which is used as once daily. If patients fail to take the dose, must get advice from medical practitioner and follow the instructions. Patient maintain the regular dosing schedule for avoiding the over dosage problem.