Effects of colchicine and phenothiazine on biliary excretion of organic anions in rats

Colchicine for the treatment of pericarditis

Colchicine has been effectively used in the treatment of several inflammatory conditions, such as gouty attacks, serositis related to familial Mediterranean fever, Behçet syndrome and more recently, in acute and recurrent pericarditis. Colchicine concentrates in white blood cells, particularly polymorphonuclear cells, inhibiting tubulin polymerization, thus interfering with migration and phagocytosis, and reducing the inflammatory cycle. Although the exact number of responders is unknown, the drug has been successfully used for the treatment and prevention of recurrences and to taper corticosteroids in patients with recurrent pericarditis in several retrospective studies and an open-label, randomized trial, where the recurrence rate was halved in the treatment arm. Less evidence supports the use of the drug for the treatment of acute pericarditis, where colchicine remains optional and requires further multicenter confirmatory studies. At present, colchicine has been recommended by the 2004 European guidelines on the management of pericardial diseases for acute (class IIa) and recurrent pericarditis (class I), but its use is still unlabeled and informed consent is required for prescription. A careful monitoring of possible contraindications, drug interactions and side effects is necessary. The aim of this paper is to review the evidence that supports the use of the drug in acute and recurrent pericarditis, as well as dosing and precautions for clinical use.

Colchicine for pericarditis: hype or hope?

Colchicine has been effectively used in the treatment of several inflammatory conditions, such as gouty attacks, serositis related to familial Mediterranean fever, Behçet syndrome, and more recently also in acute and recurrent pericarditis. Growing evidence has shown that the drug may be useful to treat an acute attack and may be a way to cope with the prevention of pericarditis in acute and recurrent cases and after cardiac surgery. Nevertheless, clinicians are often sceptical about the efficacy of the drug, and concerns have risen on possible side effects and tolerability. In this review, we analyse current evidence to support the use of the drug, as well as possible harms and risks related to drug interactions, reaching the conclusion that colchicine is safe and useful in recurrent pericarditis, if specific precautions are followed, although less evidence supports its use for the treatment of acute pericarditis, where colchicine remains optional and there is a need for further multicentre confirmatory studies. This paper also reviews specific dosing and precautions for the clinical use.

Biliary excretion of sulfated bile acids and organic anions in zone 1- and zone 3-injured rats

BACKGROUND AND AIMS

There are several reports on the biliary excretion of bile acids and organic anions in zone 1- and zone 3-injured rat liver, but the results are controversial. In order to dissolve the discrepancy between previous works about the role of hepatic zonation on the hepatic handling of the substrates of multidrug resistance protein 2, the biliary excretion of sulfated bile acids, pravastatin and phenolphthalein glucuronide was studied in zone 1- and zone 3-injured rats.

METHODS

Zone 1 and zone 3 injury were caused by allyl alcohol and bromobenzene, respectively. Bile acid sulfates, pravastatin and phenolphthalein glucuronide were administered i.v. to bile duct-cannulated rats, and their biliary excretion was studied.

RESULTS

The biliary excretion of a tracer dose of taurolithocholate-3-sulfate and its excretory maximum were unchanged in zone 1 injury, but were diminished in zone 3 injury, whereas the biliary excretion of taurochenodeoxycholate-3-sulfate was unchanged in zone 1 and zone 3 injury. The biliary excretion of pravastatin and phenolphthalein glucuronide was markedly decreased only in zone 3 injury, whereas the excretory maximum of phenolphthalein glucuronide was decreased in both zone 1 and zone 3 injury.

CONCLUSIONS

These findings indicate that zone 3 is important for the biliary excretion of substrates of multidrug resistance protein 2.

Acute Myopathy in a Patient with Concomitant Use of Pravastatin and Colchicine

OBJECTIVE

To report a case of acute myopathy after concomitant use of colchicine and pravastatin.

CASE SUMMARY

A 65-year-old woman was admitted to the hospital with an acute episode of gout. She had been taking pravastatin 20 mg once daily for 6 years. On admission, blood urea nitrogen and serum creatinine levels were 48 mg/dL and 1.3 mg/dL, respectively. Colchicine 1.5 mg/day was added to the treatment regimen, but 20 days after the initiation of colchicine therapy, symmetrical proximal muscle weakness developed in the woman's legs. Physical examination, laboratory findings, and electromyelogram findings suggested myopathy. The Naranjo probability scale indicated a probable relationship between myopathy and combined therapy. Seven days after discontinuation of colchicine and pravastatin, the patient's weakness improved and enzyme levels returned to normal. Colchicine was restarted at 1.0 mg/day 5 days later; no myopathy occurred.

DISCUSSION

Hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) and colchicine are known to cause myopathy. Most of the statins and colchicine are biotransformed in the liver primarily by the CYP3A4 system, which may increase the risk of myopathy when concurrent therapy is used. However, pravastatin is not primarily metabolized by cytochrome P450 isoenzymes. The cause of myopathy in our patient may be related to the interaction of colchicine and pravastatin via P-glycoprotein. In addition, the presence of mild renal dysfunction could have contributed to the development of myopathy.

CONCLUSIONS

We suggest that clinicians be aware that neuromuscular toxicity can occur in patients with mild renal dysfunction with combined use of colchicine and pravastatin.