Efavir belongs to antiretroviral medication and contain as active constituent like Efavirenz. Efavir tablet in combination with other drugs to treat the infection caused by HIV. Efavirwithhold the HIV multiplication of virus cell and drug despitethe destruction of the immune system. Efavir may help to delay the problems arises from AIDS/HIV diseases. Efavir will not curable or preventable HIV/AIDS. The drug is prescription medicine provided under the supervision of medical practioners
USAGE OF Efavir
Efavir tablets is indicated for the treatment of HIV infection, by combining with other anti-retroviral drugs used in adult and children’s 3 months old / weight of 3.5kg
PHARMACOLOGY OF Efavir
The pharmacology of Efavirenz is similar to lamivudine.
Efavirenz is presentaction by prohibiting the activity of viral RNA directed DNA polymerase enzyme which is a reverse transcriptase.The intracellular alteration to active triphosphorylated form which is essential for the activity of efavirenz.Depending up on the cell type, the phosphorylation occurs.
The production of DNA copies of viral RNA is interceded by inhibition of reverse transcriptase. This generation is necessary for production of new viral assembly. Finally the inhibition causes cell division termination.
The maximum plasma concentration of efavirenz is attained at 5 hours. The time to maximum plasma concentration time is relatively 3 to 5 hours. The steady state of efavirenz is reached within 6 to 10 days.
Efavirenz is highly bound to human plasma protein nearly 99.5 to 99.7%.
The metabolism of efavirenz is majorly occurred by cytochrome P450 enzymes to hydrolyzed metabolites. The major isoenzymes are CYP3A & CYP2B6.
The terminal mean half life period of efavirenz is 52 to 76 hours. 14 to 34% of radiolabel should be eliminated through urine and 16-61% eliminated via feces.
The usual dose of Efavir in adults is 600mg of tablet should be given orally as a one dose by together with protease inhibitors or nucleoside analogue reverse transcriptase inhibitors. The Efavirenz concentration of should be elevated when the Efavir tablet should be administered with food which leads to increase the adverse effects associated to Efavir. The up-take drug at bed time should elevate the tolerability of nervous system symptoms.
Concomitant use of Efavir with voriconazole, the continuance dose of voriconazole should be elevated to 400mg for every 12 hours and the Efavir dose should be depletes to 300mg as a single dose.
Efavir tablets should not be broke, chew or crush. In combination with rifampin, the dose of Efavir is 800mg
The dose of Efavir should be suggested for the pediatric patients with the age of 3 years.
10 to < 15kg: given 200mg of Efavirenz
15 to <20kg: given 250mg of Efavirenz
20 to <25kg: given 300mg of Efavirenz
25 to <32.5kg: given 350mg of Efavirenz
32.5 To <40kg: given 400mg of Efavirenz
At least 40kg: given 600mg of Efavirenz
Psychiatric symptoms, Nervous system symptoms, Rash
The common side effects of Efavirenz are
Anorexia, Nausea, Vomiting, Diarrhea, Dyspepsia, Abdominal pain, Anxiety, Fatigue, Pain, Dizziness, Headache, Insomnia, Abnormal dreams, Depression
Check the patients with these problems and inform the healthcare providers
Cholesterol and triglycerides
Redistribution/accumulation of body fat, including central obesity, dorsocervical fat enlargement, peripheral wasting, facial wasting, breast enlargement.
LFTs in patients with history of hepatitis B and/or C.HepaticFunction Use Immune reconstitution syndrome. Lipids Increases in total cholesterol and triglycerides have been checked, Monotherapy Resistant virus may emerge rapidly. Convulsions Use with caution in patients with history of seizures.
CNS symptoms Liver enzymes in patients with suspected past of hepatitis B or C infection and liver toxicity. Psychiatric symptoms psychiatric disorders may be at greater risk. Some occasional reports of death by suicide, delusions, and psychosis-like behavior. Skin rash Reported in 26% of adults and 46% of children. Over dosage Symptoms Increased CNS symptoms, involuntary muscle contractions.
Hypersensitivity reactions are produced due to patients may contraindicate to the components present in the Efavir tablets.
Contraindicated drugs like,
Due to this effect, patients may affect with severe life threatening conditions.
Avoid the combinational therapy. Some of the drugs are given: Anti-migraine like ergot derivatives Benzodiazepines Calcium channel blockers GI motility agents Neuroleptics St John’s wort