Efavirenz interactions

Food & lifestyle

• high-fat foods

  Moderate

  Absorption

  Administration with food increases the plasma concentrations of efavirenz and may increase the frequency of adverse reactions. According to the product labeling, administration of efavirenz capsules (600 mg single dose) with a high-fat/high-caloric meal (894 kcal, 54 g fat, 54% calories from fat) or a reduced-fat/normal-caloric meal (440 kcal, 2 g fat, 4% calories from fat) was associated with mean increases of 39% and 51% in efavirenz peak plasma concentration (Cmax) and 22% and 17% in systemic exposure (AUC), respectively, compared to administration under fasted conditions. For efavirenz tablets, administration of a single 600 mg dose with a high-fat/high-caloric meal (approximately 1000 kcal, 500-600 kcal from fat) resulted in a 79% increase in mean Cmax and a 28% increase in mean AUC of efavirenz relative to administration under fasted conditions.

  What to do: Efavirenz should be taken on an empty stomach, preferably at bedtime. Dosing at bedtime may improve the tolerability of nervous system symptoms such as dizziness, insomnia, impaired concentration, somnolence, abnormal dreams and hallucinations, although they often resolve on their own after the first 2 to 4 weeks of therapy . Patients should be advised of the potential for additive central nervous system effects when efavirenz is used concomitantly with alcohol or psychoactive drugs, and to avoid driving or operating hazardous machinery until they know how the medication affects them.

  1 source

  1. "Product Information. Sustiva (efavirenz)." DuPont Pharmaceuticals (2001):

Conditions

Conditions in which Efavirenz needs care, as documented in this source.

• Hypercholesterolemia

  Moderate

  Increases in total cholesterol and triglycerides have resulted during treatment with efavirenz. Lipid levels monitoring should be performed before starting treatment and at periodic intervals during therapy.

  1 source

  1. "Product Information. Sustiva (efavirenz)." DuPont Pharmaceuticals (2001):

• Liver Diseases

  Moderate

  Efavirenz is primarily metabolized by the liver. Patients with liver disease may be at greater risk for adverse effects from efavirenz due to decreased drug clearance. Therapy with efavirenz should be administered cautiously in patients with liver disease. In addition, elevations in serum transaminases to greater than five times the upper limit of normal as well as acute liver failure requiring transplantation have occurred during therapy with efavirenz, most often in patients with a prior history of Hepatitis B and/or C. Monitoring of liver function tests is recommended in these patients.

  2 sources

  1. "Product Information. Sustiva (efavirenz)." DuPont Pharmaceuticals (2001):
  2. Elsharkawy AM, Schwab U, McCarron B, et al. "Efavirenz induced acute liver failure requiring liver transplantation in a slow drug metaboliser." J Clin Virol 58 (2013): 331-3

• Long QT Syndrome

  Moderate

  QTc prolongation has been observed with the use of efavirenz. Alternatives to efavirenz should be considered when administered to patients at higher risk of torsade de pointes or when coadministered with a medication with known risk of torsade de pointes.

  1 source

  1. "Product Information. Sustiva (efavirenz)." DuPont Pharmaceuticals (2001):

• Mental Disorders

  Moderate

  During clinical trials, there have been infrequent reports of delusions and inappropriate behavior associated with the use of efavirenz, predominantly in patients with a history of mental illness or substance abuse. Severe acute depression, including suicide attempts and suicidal ideation, has also been reported but was not limited to efavirenz treated patients. Therapy with efavirenz should be administered cautiously in patients with a current or past history of psychiatric illness, emotional instability, or substance abuse. If symptoms develop or worsen during treatment, discontinuation of efavirenz may be necessary.

  1 source

  1. "Product Information. Sustiva (efavirenz)." DuPont Pharmaceuticals (2001):

• Seizures

  Moderate

  Convulsions have been observed in adult and pediatric patients receiving efavirenz, generally in the presence of known medical history of seizures. Caution should be taken with any patient with a history of seizures. Anticonvulsant medication such as phenytoin and phenobarbital may require periodic monitoring of plasma levels.

  1 source

  1. "Product Information. Sustiva (efavirenz)." DuPont Pharmaceuticals (2001):

Therapeutic duplication

Drug classes that overlap with Efavirenz, so taking both doubles up the same effect. This source publishes no per-row citations for duplication.

• nnrtis

  The recommended maximum number of medicines in the 'NNRTIs' category to be taken concurrently is usually one.Your list includes two medicines belonging to the 'NNRTIs' category.

  Example product in the source data (US market): Emtricitabine/rilpivirine/tenofovir

• nnrtis

  The recommended maximum number of medicines in the 'NNRTIs' category to be taken concurrently is usually one.Your list includes two medicines belonging to the 'NNRTIs' category.

  Example product in the source data (US market): Doravirine/lamivudine/tenofovir

• nnrtis

  The recommended maximum number of medicines in the 'NNRTIs' category to be taken concurrently is usually one.Your list includes two medicines belonging to the 'NNRTIs' category.

  Example product in the source data (US market): Emtricitabine/rilpivirine/tenofovir alafenamide

• nnrtis

  The recommended maximum number of medicines in the 'NNRTIs' category to be taken concurrently is usually one.Your list includes two medicines belonging to the 'NNRTIs' category.

  Example product in the source data (US market): Juluca

• nnrtis

  The recommended maximum number of medicines in the 'NNRTIs' category to be taken concurrently is usually one.Your list includes two medicines belonging to the 'NNRTIs' category.

  Example product in the source data (US market): Cabotegravir/rilpivirine