COMT eliminates biologically active catechols present in catecholamines (dopamine, norepinephrine, and epinephrine) and their hydroxylated metabolites. When administered with a decarboxylase inhibitor, COMT acts as the major metabolizing enzyme for levodopa and metabolizes it to 3-methoxy-4-hydroxy-L-phenylalanine (3-OMD) in the brain and in the periphery.For the treatment of Parkinsons disease, entacapone is given as an adjunct to levodopa and an aromatic amino acid decarboxylase inhibitor, carbidopa. Entacapone inhibits COMT in the periphery (but not, or at most marginally, in the brain) and the metabolism of levodopa, thus increasing plasma levels of levodopa and causing more constant dopaminergic stimulation in order to reduce the signs and symptoms presented in the disease. Pharmacokinetics
Absorption
The time to highest blood plasma concentrations is approximately one hour. The substance undergoes extensive first-pass metabolism. Absolute oral bioavailability (F) is 35%. Distribution
The volume of distribution  (Vd) after intravenous injection is approximately 20 liters. 98% of the circulating entacapone is bound to serum albumin, which limits its distribution into tissues. Metabolism and elimination
Entacapone is primarily metabolized to its glucuronide in the liver, and 5% are converted into the Z-isomer. It has a half-life of approximately 0.3–0.7 hours, with only 0.2% being excreted unchanged in the urine. References
External links
"Entacapone". Drug Information Portal. U.S. National Library of Medicine.
Heat cramps, a type of heat illness, are muscle spasms that result from loss of large amount of salt and water through exercise. Heat cramps are associated with cramping in the abdomen, arms and calves. This can be caused by inadequate consumption of fluids or electrolytes. Heavy sweating causes heat cramps, especially when the water is replaced without also replacing salt or potassium.Although heat cramps can be quite painful, they usually dont result in permanent damage, though they can be a symptom of heat stroke or heat exhaustion. Heat cramps can indicate a more severe problem in someone with heart disease or if they last for longer than an hour.In order to prevent them, one may drink electrolyte solutions such as sports drinks during exercise or strenuous work or eat potassium-rich foods like bananas and apples. When heat cramps occur, the affected person should avoid strenuous work and exercise for several hours to allow for recovery. See also
Dehydration

References
External links
Heat cramps first aid