Comparison of effectiveness of thyrotropin-suppressive doses of D- and L-thyroxine in treatment of hypercholesterolemia.
In an attempt to compare the cholesterol-lowering effects of equivalent doses of D- and L-thyroxine, 10 euthyroid, hypercholesterolemic subjects were treated with graded doses of each medication in a cross-over design using thyrotropin suppression following thyrotropin-releasing hormone administration as the end-point. The mean thyrotropin-suppressive dose of D-thyroxine was 2.4 +/- 0.66 mg per day, which resulted in mean reductions of 10 percent in total plasma cholesterol, 10 percent in plasma low-density lipoprotein cholesterol, and 11 percent in plasma high-density lipoprotein cholesterol. The mean thyrotropin-suppressive dose of L-thyroxine was 135 +/- 46 micrograms per day, which resulted in mean reductions of 7 percent in total plasma cholesterol, 6 percent in plasma low-density lipoprotein cholesterol, and 14 percent in plasma high-density lipoprotein cholesterol. The reductions in total, low-density, and high-density cholesterol achieved with D-thyroxine were not significantly different from those achieved with L-thyroxine. Neither medication produced a significant increase in heart rate or ventricular ectopy as determined by Holter monitoring. These data do not support the belief that D-thyroxine has a preferential cholesterol-lowering effect in humans when compared with equivalent doses of L-thyroxine. In addition, both D- and L-thyroxine reduced plasma high-density lipoprotein cholesterol.
D000328:Adult; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D003918:Dextrothyroxine / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006937:Hypercholesterolemia / Q000097:blood / Q000188:drug therapy*; D008075:Lipoproteins, HDL / Q000097:blood; D008077:Lipoproteins, LDL / Q000097:blood; D008297:Male; D008875:Middle Aged; D013972:Thyrotropin / Q000378:metabolism*; D013974:Thyroxine / Q000627:therapeutic use*; D014280:Triglycerides / Q000097:blood
D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D014280:Triglycerides; D003918:Dextrothyroxine; D013972:Thyrotropin; D002784:Cholesterol; D013974:Thyroxine