Tenofovir: use, side effect, mechanism of action, price
Tenofovir is used for the treatment of Human immunodeficiency virus (HIV) .it use as single content and combination dose with other content. it is available in the salt form as Tenofovir Disoproxil fumarate. it also uses for hepatitis B .it cures the hepatitis B completely if you take the proper doses as per doctor's instruction.
|Tenofovir 300 mg Tablets|
Tenofovir side effect
It produces few side effects like nausea, vomiting, pain, fever, flatulence, abdominal discomfort, loose motions and headache. Some most importance but less side effect are renal toxicity, a slightly increase in serum creatinine. skin rash is occur some time.
Tenofovir mechanism of action
Tenofovir comes under the Nucleoside reverse transcriptase inhibitor. Tenofovir is use as prodrug use as disoproxil ester. Tenofovir is also known as acyclic nucleoside phosphonate diiaster analog of adenosine monophosphate. As you know it is prodrug it converted to tenofovir diphosphate in the presence of an enzyme.
When virus capsid enter into the cell,viral plasmid are disoved . RNA OF virus are in the cell .here enzyme nucleoside reverse transcriptase are acted on this work . this enzyme having RNA depended DNA polymerase which is help to produce complementary nucleotides and DNA strand are made. Other domain of Nucleoside reverse transcriptase are destroying the Parent virus RNA .so domain of DNA are free for make fully double strand DNA . DNA polymerase are made with nucleotide which having hydroxyl group , combination of hydroxyl group are create chain.
Tenofovir is enters into the viral DNA and there are changes of stop the DNA Polymerase chain creation .Tenofovir has very low affinity towards the host DNA polymerase .
For more information about HIV virus replication you must read my previous post.
Absorption of tenofovir
Tenofovir has very low absorption capacity . some study fasting patient tenofovir bioavailability is 25%. Tenofovir Disoproxil fumarate is pro drug of tenofovir which is more water soluble in nature. If a fasted patient is taken Tenofovir disoproxil fumarate 300 mg for the treatment of HIV 1 virus maximum serum concentration are achive in 1 hour. It is not complete absolved in our body but required amount is absolved if you take orally. Tenofovir is absorption is increases if you take it with food .high fat contain food is increase 1 hour cmax vale as compaired to the fasted stage.
Plasma binding capacity of tenofovir is less than 0.7 and 7.2 % respectively.
Tenofovir metabolism enzyme is not known clearly. but it not metabolized by the cytochrome P450 or substrate. It elimination is mainly occurs in urine .about 80% is eliminate as unchanged form within 70 hours if the patient is taking tenofovir disoproxil fumarate 300 mg a day. Elimination is occur by glomerular filtration and active tubular secretion.
For the treatment of HIV 1 and chronic hepatitis B Tenofovir disoproxil fumarate 300 mg oral dose is working good with food.
Pediatric patient below or with age 12 takes Tenofovir disoproxil fumarate 300 mg with food is working good for the treatment of HIV 1.
The patient which have kidney problem the dose of this medicine is same but the frequency of dose is depend on the creatinine clearance .if creatine clearance is >50 then dose is taken every 24 hour, 30-49 ml/min then dose is taken every 48 hour.
For the hemodialysis patient there are no dose are selected .for the treatment contact your doctor.
Tenofovir are shown contraindication with other HIV treatement drug .like tenofovir with emtricitabine or efaverinz , emtricitabine and tenofovir.
In Hepatitis B patient who take nucleoside –treatment navie or lamivudine compression with liver disease.
Tenofovir causes lactic acidosis and severe hepatomegaly with steatosis when it take along with other nucleoside analogs or other antiretrovirals medicine. Mainly women are more affected by this lactic acidosis. When you take tenofovir exercise must doing regularly because it increases obesity. Mainly it affect the liver so if person having any lever problem please consult your doctor for taking advice.
If any person is the treatment of hepatitis B with tenofovir for long duration and he discontinue the medicine or stop taking medicine this person are taken observation for several month.
This medicine is mainly excreted through kidney so there are many chances of renal failure.
Interaction with other drugs
Tenofovir when taking with Didanosine it increases the adverse effect of didanosine .if the patient takes didanosine with this medicine and didanosine adverse effect increases the immediately stop the medication.
This medicine increase the Cmax of didanosine. Mechanism is unknown.
This medicine also interaction with Atazanavir. Atazanavir is increase the absorption of tenofovir , mechanism is unknown. If the patient is take both of medicine then patient is take monitoring by doctor.
This medicine also interaction with lopinavir and ritonavir .lopinavir and ritonavir is increase the concentration of tenofovir. Mechanism of action is unknown.
This medicine is excreated by kidney so if any medicine is affect the renal system .tenofovir is interaction with this medicine.
Storage condition of Tenofovir
This medicine is stored in the room temperature, which is 20°C to 25°C. Keep this medicine away form the children for safety purpose. If the medicine box or pack is unsealed then don’t take this medicine. container pack is containing desiccant which is help prevent moisture. Before taking this medicine check the expiry of box.
Tenofovir sold in the market as Viread which is manufacture by cipla .it is abbreviated as TDF. And also some brand name ever . it is taken as oral dosage form. It is also available in combination of medicine as name odemune tablets.
Price of the medicine
Price of Viread 300 mg tablets is 1379 rupees for 30 tablets in India. Which is given mylan pharmaceuticals pvt ltd.
Tenvir 300 mg tablets price is 1487.98 rupees for 30 tablets in India .which is manufactured by cipla.
This medicine is very costly.
Tenofovir is synthesize in 1984 by Antonin Holy in the institute of Organic and Biochemestry in prague. And its mechanism of action is describe in 1985.
Tenofovir Disoproxil was approved in 2001 october 26 for treatement of HIV AIDS by USFDA . And again it approve by USFDA for Hepatitis B in the 2008 August 11.