In one study, mortality has been estimated as low as just 1% in studies of hospitalized patients, to as high as 88% in untreated, unhospitalized patients. In developed countries, where the disease rarely occurs, it is recommended to seek the advice of a specialist in infectious disease when diagnosed. Mortality is often thought to be due to subsequent infections due to the weakened immune symptoms and opportunistic pathogen invasion, or consequences of malnutrition due to weight loss in children. In a study focusing on pediatric and gestational effects of the disease,  mortality rates for pregnant women with the acute phase were estimated at 40% and rates of spontaneous abortion in another 40%. Chronic phase
It is also called the eruptive phase or tissue phase, in which the patients develop a cutaneous rash produced by a proliferation of endothelial cells and is known as "Peruvian warts" or "verruga peruana". Depending on the size and characteristics of the lesions, there are three types: miliary (1–4 mm), nodular or subdermic, and mular (>5mm). Miliary lesions are the most common. The lesions often ulcerate and bleed.The most common findings are bleeding of verrugas, fever, malaise, arthralgias (joint pain), anorexia, myalgias, pallor, lymphadenopathy, and liver and spleen enlargement.On microscopic examination, the chronic phase and its rash are produced by angioblastic hyperplasia, or the increased rates and volume of cell growth in the tissues that form blood vessels. This results in a loss of contact between cells and a loss of normal functioning.The chronic phase is the more common phase.
It was recommended that the drug remain available only for patients with severe epilepsy for whom the benefits outweigh the risks, and that changes be made to the products labelling to reflect the newly recognized risk. This redemption came with an additional warning since there had been 10 cases acute liver failure (4 of which were fatal). At this point, 10,000 to 12,000 people remained on the drug. United Kingdom
The drug is only available on a limited named-patient basis. Indications and usage
Adults: Monotherapy or adjunctive therapy in the treatment of partial seizures, with and without generalization. Children: Adjunctive therapy in the treatment of partial and generalized seizures associated with Lennox-Gastaut syndrome. Dosing
Felbamate is available in tablets (400 mg and 600 mg) and as a peach-coloured oral suspension (600 mg/5 mL). Adults (≥ 14 years): begin with 1,200 mg daily given every 6 to 8 hours
Children (2–14 years): 15 to 45 mg per kg per day given every 6 to 8 hours

Side effects
Adverse reactions include decreased appetite, vomiting, insomnia, nausea, dizziness, somnolence, and headache. Many patients report increased alertness with the drug. Two rare but very serious effects include aplastic anemia and serious liver damage. The risk of aplastic anemia is between 1:3,600 and 1:5,000, of which 30% of cases are fatal. The risk of liver damage is between 1:24,000 to 1:34,000, of which 40% of cases are fatal. Drug interactions
Felbamate is an inhibitor of CYP2C19 - an enzyme involved in the metabolism of several commonly used medications.