Common Rash, Headache, Dizziness, Decrease in granulocyte count, Insomnia (difficulty in sleeping), Sleepiness, Vomiting, Allergic reaction, Nausea, Abnormal dreams, Fatigue, Increased liver enzymes, Anxiety, Fever, Itching, Difficulty in paying attention, Increased triglyceride level in blood.

Expert advice for Efferven Tablet

Inform your doctor if you have a history of mental illness or convulsions (fits or seizures).
Ensure that efavirenz is always taken in combination with other anti-HIV medicines and never alone.
Seek immediate medical attention if you develop signs of dizziness, difficulty sleeping, drowsiness, difficulty concentrating or abnormal dreaming or any signs of skin rash or inflammation or infection.
Take the required precautions to prevent transmission as efavirenz does not prevent the spread of HIV virus to others through blood or sexual contact.
Do not drive if you have taken efavirenz as it may cause dizziness.
Do take if  allergic to efavirenz or any of its ingredients.
Do not take if sufering  with severe liver disease.
Avoid if patient is Pregnant or breastfeeding women.