Tenofovir disoproxil is a type of medicine known as an antiretroviral drug, which is used to treat HIV and chronic hepatitis B. HIV is a sexually transmitted illness that eventually progresses to Acquired Immunodeficiency Syndrome. Chronic hepatitis B is a prolonged viral infection caused by the hepatitis B virus. It is a nucleotide reverse transcriptase inhibitor that interferes with the normal function of enzymes required for viral generation. It successfully alleviates symptoms associated with HIV and chronic hepatitis B infection. It was first authorized in 2001.
BRAND NAMES:
Atripla: It is the combination of efavirenz, emtrcitibine, and tenofovir. It is available in the form of tablets used to treat HIV-1 infection.
Complera: It is a combination of emtricitabine, rilpivirine, and tenofovir. It is available in the form of tablets used to treat a complete regimen for the treatment of HIV-1 infection.
MECHANISM OF ACTION:
Tenofovir diphosphate inhibits HIV-1 reverse transcriptase and Hepatitis B polymerase by direct binding competition with the natural DNA substrate and incorporation into DNA, resulting in viral DNA chain termination.
PHARMACOKINETICS:
Absorption: Tenofovir oral dosing resulted in a peak plasma time of 1 hour while fasting and 2 hours after meal consumption. Tenofovir has a bioavailability of 25%, which climbs to 40% following a high-fat diet.
Distribution: The volume of distribution of tenofovir at steady-state is 1.3 L/kg and 1.2 L/kg.
Metabolism: Tenofovir bisoprolol fumarate is quickly converted to tenofovir, which is then metabolized intracellularly to the active metabolite tenofovir diphosphate, which inhibits HIV-1 reverse transcriptase and ends the developing DNA chain. Tenofovir is not metabolized by any cytochrome P450.
Excretion:Tenofovir is excreted through urine.
PHARMACODYNAMICS:
This medication reduces viral DNA chain elongation in HIV-1 and hepatitis B infections by inhibiting enzymes required for host cell infection and viral replication.
DOSAGE AND ADMINISTRATION:
Tenofovir is available as a tablet to be taken orally. Typically, the pill is taken once a day, with or without meals. The powder is typically consumed with meals once a day. It is available as tablets with strengths of 150mg, 200mg, 250mg, and 300mg.
DRUG INTERACTIONS:
Drug interactions with tenofovir may include
Bacterial infection medicines: aminoglycosides, vancomycin
Hepatitis B virus drugs: adefovir, dipivoxil
Antifungal medicine—amphotericin B
Anti-viral drugs: didanosine and ganciclovir
Immunotherapy: interleukin-2
Immune suppressant: tacrolimus
SIDE EFFECTS:
Side effects of tenofovir may include
Depression
Diarrhea
Headache
Fever
Rash
Itching
Weight loss
Difficulty falling asleep
Some side effects can be serious; they may include
Swelling of feet
Decreased urination
Pain in the arms, hands, feet, or legs
Dizziness
Cold hands
Irregular heartbeat
Pain in the upper right part of the stomach
Shortness of breath
OVERDOSE:
Symptoms of overdose may include
Trouble breathing
Unusual muscle pain
Stomach pain
Vomiting
Fast heartbeat
Dizziness
Feeling weak or tired
TOXICITY:
Tenofovir is an antiretroviral therapy drug that can cause toxicity to the kidneys and bones.
