These pills begin acting fifteen to forty minutes after they are swallowed, and their effects last from five to six hours. Slang terms for barbiturates include barbs, barbies, bluebirds, dolls, wallbangers, yellows, downers, goofballs, sleepers, reds & blues, and tooties. Examples
Thiopental is a barbiturate with one of the C=O double bonds (with the carbon being labelled 2 in the adjacent diagram) replaced with a C=S double bond, R1 being CH2CH3 and R2 being CH(CH3)CH2CH2CH3. Thiopental is no longer available in the United States. See also
Benzodiazepine
Psycholeptic
Dille–Koppanyi reagent, Zwikker reagent, and others spot tests for barbiturates

Notes
References
External links and further reading

U.S. Drug Enforcement Administration Source for some public-domain text used on this page. López-Muñoz, F.; Ucha-Udabe, R.; Alamo, C. (2005). "The history of barbiturates a century after their clinical introduction". Neuropsychiatric Disease and Treatment. 1 (4): 329–343. PMC 2424120. PMID 18568113. National Institute on Drug Abuse: "NIDA for Teens: Prescription Depressant Medications".
While anemia is the most common cytopenia in MDS patients, given the ready availability of blood transfusion, MDS patients rarely experience injury from severe anemia. The two most serious complications in MDS patients resulting from their cytopenias are bleeding (due to lack of platelets) or infection (due to lack of white blood cells). Long-term transfusion of packed red blood cells leads to iron overload. Genetics
The recognition of epigenetic changes in DNA structure in MDS has explained the success of two (namely the hypomethylating agents 5-azacytidine and decitabine) of three (the third is lenalidomide) commercially available medications approved by the U.S. Food and Drug Administration to treat MDS. Proper DNA methylation is critical in the regulation of proliferation genes, and the loss of DNA methylation control can lead to uncontrolled cell growth and cytopenias. The recently approved DNA methyltransferase inhibitors take advantage of this mechanism by creating a more orderly DNA methylation profile in the hematopoietic stem cell nucleus, thereby restoring normal blood counts and retarding the progression of MDS to acute leukemia.Some authors have proposed that the loss of mitochondrial function over time leads to the accumulation of DNA mutations in hematopoietic stem cells, and this accounts for the increased incidence of MDS in older patients. Researchers point to the accumulation of mitochondrial iron deposits in the ringed sideroblast as evidence of mitochondrial dysfunction in MDS. 5q- syndrome
Since at least 1974, the deletion in the long arm of chromosome 5 has been known to be associated with dysplastic abnormalities of hematopoietic stem cells.