Lamivudine

In this article, we will discuss about Lamivudine (Brief Note). So, let’s get started

Lamivudine

Mechanism of action

Lamivudine is a nucleoside analogue which has activity against human immunodeficiency virus (HIV) and hepatitis B virus (HBV). It is metabolised intracellularly to the active moiety, lamivudine 5′- triphosphate. Its main mode of action is as a chain terminator of viral reverse transcription. The triphosphate has selective inhibitory activity against HIV-1 and HIV-2 replication in vitro; it is also active against zidovudine-resistant clinical isolates of HIV. No antagonistic effects in vitro were seen with lamivudine and other anti retrovirals (tested agents: abacavir, didanosine, nevirapine and zidovudine).

Dosage

Adults, adolescents and children who weigh at least 25 kg: The usual dose of Epivir is 300 mg a day. This can be taken as either one 150 mg tablet twice a day (leaving approximately 12 hours between each dose), or two 150 mg tablets once a day as advised by your doctor.

Children weighing at least 20 kg and less than 25 kg: The usual dose of Epivir is 225 mg a day. This can be given as 75 mg (half a 150 mg tablet) in the morning and 150 mg (one whole 150 mg tablet) in the evening, or 225 mg (one and a half 150 mg
tablets) once a day as advised by your doctor.

Children weighing at least 14 kg and less than 20 kg: The usual dose of Epivir is 150 mg a day. This can be given as 75 mg (half a 150 mg tablet) twice a day (leaving approximately 12 hours between each dose), or 150 mg (one 150 mg tablet) once a day as advised by your doctor.

An oral solution is also available for the treatment of children over 3 months of age, or for people who need a lower dose than usual, or who cannot take tablets.

Adverse effects

The following adverse reactions have been reported during therapy for HIV disease with Epivir. The adverse reactions considered at least possibly related to the treatment are listed below by body system, organ class and absolute frequency. Frequencies are defined as very common (≥1/10), common (≥1/100 to <1/10), uncommon (≥1/1,000 to <1/100), rare (≥1/10,000 to <1/1.000), very rare (<1/10,000). Within each frequency grouping, undesirable effects are presented in order of decreasing
seriousness.

Blood and lymphatic systems disorders
Uncommon: Neutropenia and anaemia (both occasionally severe), thrombocytopenia
Very rare: Pure red cell aplasia

Metabolism and nutrition disorders
Very rare. Lactic acidosis

Nervous system disorders
Common. Headache, insomnia
Very rare: Peripheral neuropathy (or paraesthesia)

Respiratory, Thoracic and mediastinal disorders
Common: Cough, nasal symptoms

Gastrointestinal disorders
Common: Nausea, vomiting, abdominal pain or cramps, diarrhoea
Rare: Pancreatitis, elevations in serum amylase

Hepatobiliary disorders
Uncommon: Transient elevations in liver enzymes (AST, ALT)
Rare: Hepatitis

Skin and subcutaneous tissue disorders
Common: Rash, alopecia
Rare: Angioedema

Musculoskeletal and connective tissue disorders
Common: Arthralgia, muscle disorders
Rare: Rhabdomyolysis

General disorders and administration site conditions
Common: Fatigue, malaise, fever

Weight and levels of blood lipids and glucose may increase during antiretroviral therapy.

In HIV-infected patients with severe immune deficiency at the time of initiation of combination antiretroviral therapy (CART), an inflammatory reaction to asymptomatic or residual opportunistic infections may arise. Autoimmune disorders (such as Graves’ disease and autoimmune hepatitis) have also been reported to occur in the setting of immune reactivation; however, the reported time to onset is more variable and these events can occur many months after initiation of treatment.

Cases of osteonecrosis have been reported, particularly in patients with generally acknowledged risk factors, advanced HIV disease or long-term combined antiretroviral exposure (CART).

Overdose

Administration of lamivudine at very high dose levels in acute animal studies did not result in any organ toxicity. Limited data are available on the consequences of ingestion of acute overdoses in humans. No fatalities occurred, and the patients recovered. No specific signs or symptoms have been identified following such overdose. If overdosage occurs the patient should be monitored, and standard supportive treatment applied as
required. Since lamivudine is dialysable, continuous haemodialysis could be used in the treatment of overdosage, although this has not been studied.

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