Nicotine acid test

The nicotine acid test (50 mg nicotine acid i.v.) produces a rise in bilirubin of more than 0.9 mg/dl in excess of the initial value, measured at 4 hours after the injection. The specificity and sensitivity of this test are almost 100%. (35, 42, 62)... 

Rdllinghoff, W., Paumgartner, G., Preisig, R. Nicotinic acid test in the diagnosis of Gilbert s syndrome correlation with bilirubin clearance. Gut 1981 22 663-668... 

As with many of the vitamins, biological assays have an important historical role and are widely used. For example, microbiological assays use l ctobacillusplantarum ATCC No. 8014 (57,59) or l ctobacillus arabinosus (60). These methods are appropriate for both nicotinamide and nicotinic acid. Selective detection of nictonic acid is possible if l euconostoc mesenteroides ATCC No. 9135 is used as the test organism (61). The use of microbiological assays have been reviewed (62). 

The kinetics of reaction of DABCO (7.66) and nicotinic acid (7.67 R = COOH) with the aminochlorotriazine dye Cl Reactive Red 3 (7.2) were studied under neutral conditions at temperatures in the range 100-130 °C. Quaternisation by DABCO was much more rapid than by nicotinic acid under these conditions. Neutral exhaust dyeing tests at 130 °C using the bis(aminochlorotriazine) analogue Cl Reactive Red 120 (7.48 X = Cl) with the two catalysts confirmed these trends, in that the degree of fixation was greatly increased by DABCO but nicotinic acid showed no appreciable catalytic effect [60]. This difference may be attributable to steric strain of the C-N+ bond in the quaternised triazine structure by the non-planar DABCO substituent. 

Increased bilirubin levels are caused due to the intake of large doses of such drugs as chloroquine, vitamin K, sulpha-drugs, tetracyclines, paracetamol, nicotinic acid and monoamine oxidase inhibitors (e.g., iproniazid RP 1.0 nialamide RP 1.8 isocarboxazid RP 3.1 phenelzine RP 18 pheniprazine RP31 and tranylcypromine RP 45), where RP designates the Relative Potency based on the tiyptamine potentiation test. The elevated levels are due to hepatic injury, and... 

Perform liver function tests on all patients during therapy with nicotinic acid. Monitor serum transaminase levels, including ALT and AST, before treatment begins, every 6 to 12 weeks for the first year, and periodically thereafter (at approximately 6-month intervals). Discontinue the drug if the transaminase levels show evidence of progression, particularly if they rise to 3 times the upper limit of normal and are persistent or if they are associated with symptoms of nausea, fever, or malaise. Consider liver biopsy if elevations persist beyond discontinuation. 

Nicotinic acid is present in the more active GTF preparations isolated from yeasts. The coordination chemistry of this ligand is particularly relevant to glucose tolerance and the presence of this substance is apparently essential for the maximal activity of complexes in tests in vitro. The instability of highly purified GTF fractions has frequently been noted this may arise because the substance in vivo is stabilized by a protein. 

Severe toxicoderma has been reported with xanthinol nicotinate and confirmed by a provocation test (SEDA-1, 333). Flushing is claimed to be less frequent with xanthinol nicotinate than with nicotinic acid, but has nevertheless been repeatedly observed, and its other adverse effects are likely to be the same as those of nicotinic acid. 

Late adverse effects include hepatic dysfunction, with altered liver function tests and hyperbilirubinemia. After prolonged use of nicotinic acid and nicotinyl alcohol, histological changes, for example parenchymal cell injury, portal fibrosis, cholangitis, cholestasis, biliary casts, and lymphocytic infiltrations around the bile ducts, have occasionally been seen. 

The peculiarities of tryptophan metabolism in the 15 individual members of this family were demonstrated by oral ingestion of 10 g DL-tryp-tophan per test case and quantitative determination of the urinary content of kynurenine, 3-hydroxykynurenine, xanthurenic acid, nicotinic acid amide and its N -methyl derivative, and 4-pyridoxic acid. Of the 15 members of the family examined 6 showed, repeatedly, abnormal levels of... 

Statins are well absorbed after administration orally, and are metabolised in the liver. They are well tolerated, the commonest adverse effect being transient, and usually minor abnormality of liver function tests in some 1% of patients. Asymptomatic elevation of muscle enzymes (creatine phos-phokinase, CPK) and myositis (with a generalised muscle discomfort) occur more rarely, but is more frequent when statins are combined with other anti-hyperlidaemic drugs such as fibrates and nicotinic acid patients should be counseled about myositis when these drugs are co-administered. Myositis is also more likely with co-administered anti-HIV protease inhibitors, and with drugs that interfere with metabolism of some statins, e.g. ciclosporin. 

Equations 28 and 29 can also be used to predict the Jr values of the esters of nicotinic acid, whose measurement points have not been taken into consideration in the equation. A test was performed on Eqs. 28 and 29 to determine how well they predict r values of points not included in the training set. Three values were removed from the training sets (Eqs. 28 and 29). Isopropyl nicotinate (separated in benzene methanol, 5 5, voFvol) and ethyl nicotinate (separated in benzene methanol, 4 6, and 0 10, voFvol) from Eqs. 28 and 29 were removed. This subset of two parametric equations was recalculated as ... 

---