To further prevent infection, the WHO recommends testing all donated blood for hepatitis B before using it for transfusion. Using antiviral prophylaxis to prevent mother-to-child transmission is also recommended, as is following safe sex practices, including the use of condoms In 2016, the WHO set a goal of eliminating viral hepatitis as a threat to global public health by 2030. Achieving this goal would require the development of therapeutic treatments to cure chronic hepatitis B, as well as preventing its transmission and using vaccines to prevent new infections.An estimated 296 million people, or 3.8% of the global population, had chronic hepatitis B infections as of 2019. Another 1.5 million developed acute infections that year, and 820,000 deaths occurred as a result of HBV. Cirrhosis and liver cancer are responsible for most HBV-related deaths. The disease is most prevalent in Africa (affecting 7.5% of the continent’s population) and in the Western Pacific region (5.9%). Infection rates are 1.5% in Europe and 0.5% in the Americas. According to some estimates, about a third of the worlds population has been infected with hepatitis B at one point in their lives. Hepatitis B was originally known as "serum hepatitis". Signs and symptoms
Acute infection with hepatitis B virus is associated with acute viral hepatitis, an illness that begins with general ill-health, loss of appetite, nausea, vomiting, body aches, mild fever, and dark urine, and then progresses to development of jaundice. The illness lasts for a few weeks and then gradually improves in most affected people.
Overdose
Up to eightfold therapeutic doses have been given in studies without problems. Interactions
Rolapitant moderately inhibits the liver enzyme CYP2D6. Blood plasma concentrations of the CYP2D6 substrate dextromethorphan have increased threefold when combined with rolapitant; and increased concentrations of other substrates are expected. The drug also inhibits the transporter proteins ABCG2 (breast cancer resistance protein, BCRP) and P-glycoprotein (P-gp), which has been shown to increase plasma concentrations of the ABCG2 substrate sulfasalazine twofold and the P-gp substrate digoxin by 70%.Strong inducers of the liver enzyme CYP3A4 decrease the area under the curve of rolapitant and its active metabolite (called M19); for rifampicin, this effect was almost 90% in a study. Inhibitors of CYP3A4 have no relevant effect on rolapitant concentrations. Pharmacology
Pharmacodynamics
Both rolapitant and its active metabolite M19 block the NK1 receptor with high affinity and selectivity: to block the closely related receptor NK2 or any other of 115 tested receptors and enzymes, more than 1000-fold therapeutic concentrations are necessary. Pharmacokinetics
Rolapitant is practically completely absorbed from the gut, independently of food intake. It undergoes no measurable first-pass effect in the liver. Highest blood plasma concentrations are reached after about four hours. When in the bloodstream, 99.8% of the substance are bound to plasma proteins.It is metabolized by the liver enzyme CYP3A4, resulting in the major active metabolite M19 (C4-pyrrolidine-hydroxylated rolapitant) and a number of inactive metabolites. Rolapitant is mainly excreted via the feces (52–89%) in unchanged form, and to a lesser extent via the urine (9–20%) in form of its inactive metabolites.