Antiretroviral drug; Nucleoside reverse transcriptaze inhibitor (NRTI)Therapeutic action
Abacavir is a synthetic nucleoside analog and inhibits HIV virus. Mechanism of action – inhibiting the activity of viral reverse transcriptase (RT). Abacavir prevents the formation of viral DNA replication.Pregnancy category
Abacavir is used to treat HIV infection in combination with other antiretroviral agents.Contraindications
- Hypersensitivity to Abacavir
- Lactic acidosis
- Creatinine clearance of less than 50 mL/min
- Severe hepatomegaly with severe steatosis;
- Moderate to severe hepatic impairment
- Patients with HLA-B*5701 allele ( they are in a high risk group for hypersensitivity reaction to this drug)
- If there is prior resistance to another nucleoside reverse transcriptase inhibitor (NRTI)
- If there is a history of cardiac disease
- With oder adults
- In pregnant women (category C drug )
- Safe use in children younger than 3 months has not been established
- Hypersensitivity reactions may occur (may manifest as fever, skin rash, fatigue, nausea, vomiting, diarrhea, abdominal
pain); malaise; lethargy; myalgias; arthralgias; paresthesias; edema; shortness of breath.
- Insomnia, headache and fever.
- Hypotension (associated with hypersensitivity reaction), heart attack.
- Hepatomegaly with steatosis, nausea, vomiting, diarrhea, anorexia, pancreatitis, increased GGT, increased liver function tests.
- Metabolic complications, particularly lactic acidosis, renal insufficiency
Tablets and oral solution of Abacavir are interchangeable on a mg-for-mg basis.
Tablets and liquid should be stored at 20°– 25° C (68°–77° F). Liquid form of this drug may be refrigerated.
Bioavailability of drug: It is 83% bioavailable.
Metabolism of drug : It is metabolized by alcohol dehydrogenase and glucuronyl transferase to inactive metabolites.
Elimination of drug : 84% of drug is found in urine, primarily as inactive metabolites;
Half-Life: 1.5 h.
Abacavir blood levels may increase with the use of alcohol.
Abacavir has been associated with very serious and sometimes fatal hypersensitivity reactions. This is especially dangerous to those patients with the HLA-B*5701 allele. This drug is also associated with lactic acidosis and severe hepatomegaly, which is sometimes fatal.Monitor
Patient should be monitored for the signs and symptoms of hypersensitivity, including: fever, skin rash, fatigue, GI distress (nausea, vomiting, diarrhea and abdominal pain). In case of hypersensitivity- drug should be withheld.
Patient should be monitored for signs and symptoms of lactic acidosis, renal insufficiency and hepatotoxicity, including: hyperventilation, lethargy,hepatomegaly, renal insufficiency. If any sign of acidosis or hepatotoxicity occurs- drug should b withheld.
Monitoring of lab tests: Prior to first administration screening for HLAB* 5701 should be done. During treatment periodic monitoring of liver function, BUN and creatinine, CBC with differential, triglyceride levels,
and blood glucose, especially in diabetics is needed.
- This drug should be taken drug exactly as prescribed at indicated times.
- If a dose is missed, then the drug should be taken immediately and the next dose of it should be taken as usual. The dose should never be doubled.
- At the first sign of hypersensitivity or liver damage, the drug should be witheld and the doctor should be informed.
- It is recommended that patient should always carry the Warning Card with him at all times.