Lamivudine and Zidovudine are synthetic nucleoside analogues with activity against human immunodeficiency virus (HIV).

Lamivudine: Intracellularly, Lamivudine is phosphorylated to its active 5’-triphosphate metabolite, Lamivudine triphosphate (L-TP). The principal mode of action of L-TP is inhibition of reverse transcription (RT) via DNA chain termination after incorporation of the nucleoside analogue. Following oral administration, Lamivudine is rapidly absorbed and extensively distributed. Binding to plasma protein is low.

Zidovudine: Intracellularly, Zidovudine is phosphorylated to its active 5’-triphosphate metabolite, Zidovudine triphosphate (ZDV-TP). The principal mode of action of ZDV-TP is inhibition of RT via DNA chain termination after incorporation of the nucleoside analogue. Following oral administration, Zidovudine is rapidly absorbed and extensively distributed. Binding to plasma protein is low. Zidovudine is eliminated primarily by hepatic metabolism.

Lamivudine and zidovudine tablets, a combination of 2 nucleoside analogue reverse transcriptase inhibitors, are indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection

Recommended Dosage for Adults and Adolescents: The recommended dosage of lamivudine and zidovudine tablets in HIV-1-infected adults and adolescents weighing greater than or equal to 30 kg is 1 tablet (containing 150 mg of lamivudine and 300 mg of zidovudine) taken orally twice daily.

Recommended Dosage for Pediatric Patients: The recommended dosage of lamivudine and zidovudine tablets for pediatric patients who weigh greater than or equal to 30 kg and for whom a solid oral dosage form is appropriate is 1 tablet administered orally twice daily on an empty stomach. Before prescribing lamivudine and zidovudine tablets, children should be assessed for the ability to swallow tablets. If a child is unable to reliably swallow a lamivudine and zidovudine tablet, the liquid oral formulations should be prescribed.

Not Recommended Due to Lack of Dosage Adjustment Because lamivudine and zidovudine tablets are a fixed-dose formulation and cannot be dose adjusted, lamivudine and zidovudine tablets are not recommended for:

• Pediatric patients weighing less than 30 kg 
• Patients with creatinine clearance less than 50 mL per minute
• Patients with hepatic impairment
• Patients experiencing dose-limiting adverse reactions. Liquid and solid oral formulations of the individual components of lamivudine and zidovudine tablets are available for these populations.

This is contraindicated in patients with previously demonstrated clinically significant hypersensitivity to any of the components of the product. Reduction of doses of Lamivudine is recommended for patients with low body weight (less than 50 kg or 110 lb); therefore, patients with low body weight should not receive Lamivudine & Zidovudine.

Side effects of this medicine-

• More common: Chills, fever, pale skin; sore throat; unusual tiredness or weakness, headache
• Less common: Abdominal pain, burning, tingling, numbness, or pain in the hands, arms, feet, or legs, muscle tenderness and weakness, nausea, skin rash, vomiting, yellow eyes or skin. Coughing, decreased appetite, diarrhea, dizziness and trouble in sleeping may occurs

Patients with HIV and Hepatitis B virus Coinfection: Safety and efficacy of Lamivudine have not been established for treatment of chronic hepatitis B in patients dually infected with HIV and HBV. Emergence of hepatitis B virus variants associated with resistance to Lamivudine has also been reported in HIV-infected patients who have received Lamivuuine-containing antiretroviral regimens in the presence of concurrent infection with Hepatitis B virus. Post-treatment exacerbations of hepatitis have also been reported.

Patients with Impaired Renal Function: Reduction of the dosages of Lamivudine and Zidovudine is recommended for patients with impaired renal function. Patients with creatinine clearance <50 ml/min should not receive this combination tablet.

Fat Redistribution: Redistribution/accumulation of body fat including central obesity, dorsocervical fat enlargement (buffalo hump), peripheral wasting, facial wasting, breast

enlargement, and cushingoid appearance have been observed in patients receiving antiretroviral therapy.

Pregnancy & Lactation

Pregnancy Category C. There arc no adequate and well controlled studies of this drug in pregnant women. This drug should be used during pregnancy only if the potential benefits outweigh the risks. The Centers for Disease Control and Prevention recommend that HIV-infected mothers should not breast-feed their infants to avoid risking postnatal transmission of HIV. Because of the potential for HIV transmission and the potential for serious adverse effects in nursing infants, mothers should be instructed not to breast feed if they are receiving efavirenz.