Indications of Tenofovir alafenamide hemifumarate

Tenofovir alafenamide hemifumarate (TAHF), also known as Tenofovir alafenamide fumarate, is a salt derivative of Tenofovir alafenamide (TA) and is considered to be the thermodynamically more stable form. Tenofovir alafenamide monofumarate form (TAMF), a precursor substance of TAHF, also belongs to the salt derivatives of TA and has the following structure:

Tenofovir alafenamide is an antiviral prescription drug approved by the FDA for the treatment of chronic hepatitis B virus infection (HBV) in adults and children 6 years of age and older who weigh at least 55 pounds (25 kg) and meet certain requirements. HBV may be an opportunistic infection (OI) for HIV.

Tenofovir alafenamide hemifumarate (TAHF) is used to treat:

• (1): HIV-1 infection.

• (2): Patients aged 18 years and older with chronic hepatitis B infection.

• (3): Chronic cholecystitis in adults 16 years of age and older with compensated liver disease and evidence of viral replication and active liver inflammation.

Mechanism of action

The antiviral properties of Tenofovir alafenamide hemifumarate are due to its ability to inhibit HBV polymerase, which in turn inhibits DNA synthesis and viral replication.

Contraindications

Contraindications to Tenofovir alafenamide hemifumarate include patients with hypersensitivity to TAHF. and patients with a history of renal disease, HIV infection, other liver disease (e.g., hepatitis C, cirrhosis), bone disease (e.g., osteopathy, osteopenia/osteoporosis, fragile bones/fractures), and pancreatic disease (pancreatitis). Please take it strictly on medical advice.

Side Effects

A common side effect of Tenofovir alafenamide hemifumarate is headache. Other side effects that may occur include diarrhoea, nausea, vomiting, dizziness, abdominal pain, bloating, joint pain or rash, and itchy skin. Less common side effects include swelling of the face, lips, or throat, and hives. It also has significant effects on on the liver, which may lead to elevated liver enzymes (ALT), impaired kidney function or cause weight gain, blood sugar, and lipid changes. Serious side effects include lactic acidosis and severe hepatomegaly with steatosis, exacerbation of hepatitis after treatment, nephrotoxicity and reduced bone density. Contact your doctor if any of these serious adverse symptoms occur.

References:

[1] HANNES LENGAUER. Co-crystals, Salts or Mixtures of Both? The Case of Tenofovir Alafenamide Fumarates.[J]. Pharmaceutics, 2020. DOI:10.3390/pharmaceutics12040342.