Trade name : Tenvir L
Active ingredient : Tenofovir disoproxil fumarate + lamivudine
Strength availability : 300mg + 300mg
Manufactured by : Cipla
Package : 30 tablets in a container
A Tenvir L tablets belongs to type of three anti-retroviral agents which includes of two components i.e Tenofovir DF, Lamivudine Tenofovir DF: adenine analogue of reverse transcriptase inhibitor & acyclic nucleoside phosphonate analogue of adenosine 5’ monophosphate Lamivudine: reverse transcriptase inhibitor, Zalcitabine analogue, nucleoside analogue Tenvir L is used to reduce the HIV viral production.
Before begin the therapy with Tenvir L, patient should be examined for presence of HBV infection or not. Follow Renal function & liver function test before the treatment. The Tenvir L recommended dose for adult suffering from HIV infection The administrated one tablet orally given onace a day with combination of other antiretroviral agents. Tenvir L is a three drug fixed dose combination; it should be administered on an empty stomach. This tablet should be consumed at bed time due to reducing the neurological problems.
NOT PRESCRIBED FOR
Patients who have creatinine clearance less than 50ml/min With severe renal impairment Hemodialysis patient Tenvir L should not be used for; Moderate & severe liver impairment patients In pediatric patients dose: The patients should weighing atleast 35kg administrated one tablet given once a day via orally with combination of other antiretroviral agents.
MECHANISM OF ACTION :
The major mechanism of Tenvir L is involved in prohibition of reverse transcriptase enzyme. The enzyme is responsible for HIV viral production. Lamivudine: Lamivudine after absorption, undergoes phosphorylation intracellularly leads to form an active moiety known as lamivudine 5’ triphosphate (nucleoside analogue). This metabolite gets inserted into DNA of HIV virus which is aided by HIV RT & HBV polymerase. Tenofovir DF; This prodrug converted into tenofovir by diester hydrolysis and gets phosphorylated to from triphosphate form (nucleoside analogue), inserted into viral cells by HIV RT enzyme causes chain termination. Tenofovir DF: chain terminator Lamivudine: chain terminator
Absorption: Tenofovir bioavailability is 25% & increases up to 40% by administering with food.
Peak plasma concentration time of Tenofovir is 1.0 plus or minus 0.4 hour
The absolute bioavailability of Lamivudine is occurs by 86% plus or minus 16%.
Lamivudine get absorbed very quickly.
Distribution: Lamivudine get binds to human plasma protein by <36% Tenofovir has low protein binding capacity by 0.7% to human plasma protein or <7.2% to serum proteins.
The metabolism of Tenvir L is occurs hepatically. Lamivudine get metabolized by undergoing biotransformation. Tenofovir metabolism is not induced by cytochrome isoenzymes.
Elimination: Lamivudine eliminated by urine. The elimination of tenofovir DF is occurs via glomerular filteration & active tubular secretion. The half lives of Tenvir L; Tenofovir: 17 hours Lamivudine: 5 to 7 hours
WARNING & PRECAUTION
Embryo fetal damage :
Tenvir L is contraindicated to pregnancy condition
Skin problems : Severe hypersensitivity reactions are produced during Tenvir L therapy. Prevent the problem by providing general supportive measures.
Aggravation of HBV : After stopping the anti-HBV drug, reactivation of HBV infection occurs. Prevent the problem by investigating the patient’s history whether suspected with HBV infection or not.
Loss of virological effects : Tenvir L is a three drug fixed dose combination; there is a chance of occurring resistance. Monitor the patient’s condition frequently.
Lactic acidosis : Prevent the problem by measuring the hepatic enzymes level In severe condition stop the Tenvir L treatment.
Nervous problem : Reduce the problem by giving Tenvir L at bed time on an empty stomach.
Liver toxicity : Monitor the liver function test Maintain the hepatic enzymes In severe condition, stop the treatment
Bone defects : During the treatment, loss of calcium levels occur causes osteomalacia Prevent the problem by providing vitamin D supplements.
Immune reconstitution syndrome : This fatal case is frequently occurred in anti-retroviral therapy. In serious condition stop the Tenvir L tablets. Fat redistribution, discontinue the Tenvir L tablets QT prolongation reduced by avoiding the concomitant use of Tenvir L with drugs which may extends the QT intervals.
Interaction with HIV-1 protease inhibitors may decrease Tenofovir AUC. Hence avoid CIMDUO should be discontinued Interaction with hepatitis C drugs may shown to increase Tenofovir exposure Tenvir L with drugs affecting the renal functions causes increased concentration of tenofovir and leads to increase the adverse effects. Tenvir L should not be combined with cannabinoids receptors Tenvir L with CYP3A inducers causes increased clearance of Tenvir L & leads to reduce the plasma concentration. Interaction of Tenvir L with warfarin causes fluctuation in prothrombin time & INR values. Tenvir L combination with anti-fungals, anti-depressants, or anti-infective causes reduced effect of concentration of these drugs. Interaction of Tenvir L with anti-malarial, anti-mycobacterials, calcium channel blockers, or lipid lowering drugs causes decreased effect of concentration of these drugs. Tenvir L should not be combined with other anti-retroviral drugs. Tenvir L should not be combined with QT prolonged drugs
Hypersensitivity reactions are produced due to patients is contraindicated to the component of Tenvir L.
In case of missed dose, patients must consult with medical practitioner & follow their instructions. Maintain the regular dosing schedule Avoid the missed dose if possible Do not self medicate the Tenvir L tablets.
Tenvir L container should be kept at temperature below 30℃ Protect away from heat, moisture & light
Common side effects :
Headache, Pain, Diarrhea, Rash , depression.
Serious side effects:
Lactic acidosis, Aggravation of HBV, Renal damage, Psychiatric problems, Nervous problems, Skin related problems, Liver toxicity, Hepatic decompensated cirrhosis, Pancreatitis, Bone defects, Immune reconstitution syndrome, Redistribution of fat.
Lab abnormalities :
Increased cholesterol, elevation of creatine kinase, increased AST & ALT, Hematuria, neutropenia, increased serum amylase.