Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Example Input: Context: Isotretinoin is effective in the treatment of severe acne and rosacea. Both parent drug and its main metabolite 4-oxo-isotretinoin are potentially teratogenic compounds and contain a carboxylic acid moiety. In the presence of ethanol, naturally occurring as well as synthetic retinoids also containing a carboxylic acid moiety are capable of undergoing an ethyl esterification with the metabolic formation of more lipophilic compounds with a much longer terminal half-life.', 'To determine if isotretinoin (13-cis-RA), its main metabolite 4-oxo-isotretinoin (4-oxo-13-cis-RA), and other possible metabolites in the presence or absence of ethanol are converted to their corresponding ethyl derivatives in patients with severe acne or rosacea after multiple isotretinoin dosing. In addition, pharmacokinetic parameters of the parent drug and its 4-oxo metabolite were determined.', 'Eleven patients with severe acne or rosacea were treated with isotretinoin daily for 3 months and investigated pharmacokinetically during 24 h after 1 month of treatment and for up to 28 days after discontinuation of therapy. A possible influence of ethanol was evaluated using a simple self-administered questionnaire and by measuring serum ethanol levels during treatment. The concentrations of isotretinoin, 4-oxo-isotretinoin and possible ethylated and nonethylated metabolites were measured by reverse-phase high-performance liquid chromatography.', "Although seven of 11 patients had a considerable weekly alcohol intake, no endogenous synthesis of ethyl derivatives of isotretinoin, the main 4-oxo metabolite or the all-trans compounds was chromatographically detectable in any of the patients' plasma samples during the treatment period. Multiple dose pharmacokinetic data for the parent drug and its main metabolite were comparable to previous studies.
Answer: The metabolism and pharmacokinetics of isotretinoin and its main metabolites are not influenced by ethanol during long-term isotretinoin treatment. After ceasing long-term isotretinoin therapy the recommended period of 1 month for using anticonceptive measures in fertile women seems adequate.
Example Output: Are the metabolism and pharmacokinetics of isotretinoin in patients with acne and rosacea influenced by ethanol?

Example Input: Context: Although diabetic patients often have gastrointestinal complications, the gastric mucosal function in diabetes has not been well documented.', 'To investigate the effect of fasting on the gastric mucosa in C57BL/KsJ-db +/+ db (db/db) mice, genetically non-insulin-dependent diabetic animals.', 'Blood glucose levels, gastric mucosal morphology, and the amount of gastric mucin were examined before and after 18 h of fasting with free access to water in db/db mice and their non-diabetic littermates (db/m).', 'Although 18 h of fasting reduced the blood glucose levels of both db/db and db/m mice, fasting decreased the amount of gastric adherent mucin and caused haemorrhagic gastric lesions only in db/db mice. After fasting, oral administration of ethanol induced much more severe gastric damage in db/db than in db/m mice. The above fasting-induced gastric damage such as haemorrhagic lesions, loss of the mucin, and the increased sensitivity to ethanol worsened as the duration of diabetes became longer. Glucose ingestion in drinking water during the fasting counteracted the fall in blood glucose and prevented the decrease in the amount of gastric mucin and the formation of gastric mucosal lesions in db/db mice.
Answer: These findings indicate that fasting-induced glucose deficit causes gastric mucosal lesions and increases the susceptibility of gastric mucosa to noxious agents owing to the loss of mucus glycoprotein in db/db mice. Prolonged diabetes is likely to augment the severity of fasting-induced impairment of the gastric mucosal function.
Example Output: Does fasting induce impairment of gastric mucosal integrity in non-insulin-dependent diabetic ( db/db ) mice?

Example Input: Context: Efavirenz frequently causes central nervous system (CNS) symptoms. We evaluated genetic associations with efavirenz discontinuation for CNS symptoms within 12 months of treatment initiation.', 'Patients had initiated efavirenz-containing regimens at an HIV primary care clinic in the Southeastern United States and had at least 12 months of follow-up data. Polymorphisms in CYP2B6 and CYP2A6 defined efavirenz metabolizer categories. Genome-wide genotyping enabled adjustment for population stratification.', 'Among 563 evaluable patients, 99 (17.5%) discontinued efavirenz within 12 months, 29 (5.1%) for CNS symptoms. The hazard ratio (HR) for efavirenz discontinuation for CNS symptoms in slow versus extensive metabolizers was 4.9 [95% confidence interval (CI): 1.9-12.4; P=0.001]. This HR in Whites was 6.5 (95% CI: 2.3-18.8; P=0.001) and 2.6 in Blacks (95% CI: 0.5-14.1; P=0.27). Considering only slow metabolizers, the HR in Whites versus Blacks was 3.1 (95% CI: 0.9-11.0; P=0.081). The positive predictive value of slow metabolizer genotypes for efavirenz discontinuation was 27% in Whites and 11% in Blacks.
Answer: Slow metabolizer genotypes were associated significantly with efavirenz discontinuation for reported CNS symptoms. This association was considerably stronger in Whites than in Blacks.
Example Output:
Does pharmacogenetics of efavirenz discontinuation for reported central nervous system symptoms appear to differ by race?