TRIENTINE HYDROCHLORIDE — trientine hydrochloride capsule
Rising Pharmaceuticals, Inc.
Trientine hydrochloride, USP is N,N’-bis (2-aminoethyl)-1,2-ethanediamine dihydrochloride. It is a white to pale yellow crystalline hygroscopic powder. It is freely soluble in water, soluble in methanol, slightly soluble in ethanol, and insoluble in chloroform and ether.
The molecular formula is C6 H18 N4 •2HCl with a molecular weight of 219.2. The structural formula is: NH2 (CH2 )2 NH(CH2 )2 NH(CH2 )2 NH2 •2HCl
Trientine hydrochloride, USP is a chelating compound for removal of excess copper from the body.
Trientine hydrochloride, USP is available as 250 mg capsules for oral administration. Trientine hydrochloride capsules, USP contain gelatin, iron oxide black, iron oxide red, iron oxide yellow, potassium hydroxide, propylene glycol, shellac, stearic acid and titanium dioxide as inactive ingredients.
Wilson’s disease (hepatolenticular degeneration) is an autosomal inherited metabolic defect resulting in an inability to maintain a near-zero balance of copper. Excess copper accumulates possibly because the liver lacks the mechanism to excrete free copper into the bile. Hepatocytes store excess copper but when their capacity is exceeded copper is released into the blood and is taken up into extrahepatic sites. This condition is treated with a low copper diet and the use of chelating agents that bind copper to facilitate its excretion from the body.
Forty-one patients (18 male and 23 female) between the ages of 6 and 54 with a diagnosis of Wilson’s disease and who were intolerant of d-penicillamine were treated in two separate studies with trientine hydrochloride. The dosage varied from 450 to 2400 mg per day. The average dosage required to achieve an optimal clinical response varied between 1000 mg and 2000 mg per day. The mean duration of trientine hydrochloride therapy was 48.7 months (range 2 to 164 months). Thirty-four of the 41 patients improved, 4 had no change in clinical global response, 2 were lost to follow-up and one showed deterioration in clinical condition. One of the patients who improved while on therapy with trientine hydrochloride experienced a recurrence of the symptoms of systemic lupus erythematosus which had appeared originally during therapy with penicillamine. Therapy with trientine hydrochloride was discontinued. No other adverse reactions, except iron deficiency, were noted among any of these 41 patients.
One investigator treated 13 patients with trientine hydrochloride following their development of intolerance to d-penicillamine. Retrospectively, he compared these patients to an additional group of 12 patients with Wilson’s disease who were both tolerant of and controlled with d-penicillamine therapy, but who failed to continue any copper chelation therapy. The mean age at onset of disease of the latter group was 12 years as compared to 21 years for the former group. The trientine hydrochloride group received d-penicillamine for an average of 4 years as compared to an average of 10 years for the non- treated group.
Various laboratory parameters showed changes in favor of the patients treated with trientine hydrochloride. Free and total serum copper, SGOT, and serum bilirubin all showed mean increases over baseline in the untreated group which were significantly larger than with the patients treated with trientine hydrochloride. In the 13 patients treated with trientine hydrochloride, previous symptoms and signs relating to d-penicillamine intolerance disappeared in 8 patients, improved in 4 patients, and remained unchanged in one patient. The neurological status in the trientine hydrochloride group was unchanged or improved over baseline, whereas in the untreated group, 6 patients remained unchanged and 6 worsened. Kayser-Fleischer rings improved significantly during trientine hydrochloride treatment.
The clinical outcome of the two groups also differed markedly. Of the 13 patients on therapy with trientine hydrochloride (mean duration of therapy 4.1 years; range 1 to 13 years), all were alive at the data cutoff date, and in the non-treated group (mean years with no therapy 2.7 years; range 3 months to 9 years), 9 of the 12 died of hepatic disease.
Preclinical Studies Studies in animals have shown that trientine hydrochloride has cupriuretic activities in both normal and copper-loaded rats. In general, the effects of trientine hydrochloride on urinary copper excretion are similar to those of equimolar doses of penicillamine, although in one study they were significantly smaller.
Renal clearance studies were carried out with penicillamine and trientine hydrochloride on separate occasions in selected patients treated with penicillamine for at least one year. Six-hour excretion rates of copper were determined off treatment and after a single dose of 500 mg of penicillamine or 1.2 g of trientine hydrochloride. The mean urinary excretion rates of copper were as follows:
|N o . of Patients||S i n g l e Dose Treatment||Basal Excretion Rate (µg Cu + + /6hr)||Test-dose Excretion R a t e (µg Cu + + /6hr)|
|4||Penicillamine, 500 mg||17||320|
In patients not previously treated with chelating agents, a similar comparison was made:
|No. of Patients||Single Dose Treatment||Basal Excretion Rate (µg Cu++ /6hr)||Test-dose Excretion Rate (µg Cu++ /6hr)|
|7||Penicillamine, 500 mg||68||1074|
These results demonstrate that trientine hydrochloride is effective as a cupriuretic agent in patients with Wilson’s disease although on a molar basis it appears to be less potent or less effective than penicillamine. Evidence from a radio-labelled copper study indicates that the different cupriuretic effect between these two drugs could be due to a difference in selectivity of the drugs for different copper pools within the body.
Data on the pharmacokinetics of trientine hydrochloride are not available. Dosage adjustment recommendations are based upon clinical use of the drug (see DOSAGE AND ADMINISTRATION).
Trientine hydrochloride is indicated in the treatment of patients with Wilson’s disease who are intolerant of penicillamine. Clinical experience with trientine hydrochloride is limited and alternate dosing regimens have not been well-characterized; all endpoints in determining an individual patient’s dose have not been well defined. Trientine hydrochloride and penicillamine cannot be considered interchangeable. Trientine hydrochloride should be used when continued treatment with penicillamine is no longer possible because of intolerable or life endangering side effects.
Unlike penicillamine, trientine hydrochloride is not recommended in cystinuria or rheumatoid arthritis. The absence of a sulfhydryl moiety renders it incapable of binding cystine and, therefore, it is of no use in cystinuria. In 15 patients with rheumatoid arthritis, trientine hydrochloride was reported not to be effective in improving any clinical or biochemical parameter after 12 weeks of treatment.
Trientine hydrochloride is not indicated for treatment of biliary cirrhosis.
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