Effect of lithium dosing schedule on urinary output

Lithium has been reported to induce polyuria in up to 35% of patients receiving it. It has been suggested that polyuria may be reduced by using single rather than multiple daily dosing. However, this information is based on non-randomized studies, which used higher serum lithium levels than are currently used. In fact, the incidence of polyuria may be lower at currently used lithium levels, and the benefits of a single daily dose regimen on urine volume at these levels have not been assessed. We conducted a prospective randomized study to test the hypothesis that switching patients from multiple daily dose lithium to single daily dose lithium would significantly lower urine volume. Twenty-four patients previously stabilized on multiple daily dosing were randomly allocated to either single or multiple daily dose lithium. Twenty-four-hour urine volume, serum creatinine, creatinine clearance and serum lithium were measured at study entry and completion. Switching to single daily dose lithium did not significantly reduce the 24-h urine volume.

Mechanism of polyuria after cisplatin therapy

Cisplatin is an antineoplastic agent. Several nephrotoxic effects are associated with its use including chronic and acute renal failure, renal magnesium wasting, and polyuria. We have investigated polyuria in groups of rats treated with cisplatin at doses of 2.5 and 5 mg/kg body weight given once weekly for 3 weeks to determine possible mechanisms of this impairment. After cisplatin administration, glomerular filtration rate was reduced and significant increases in sodium and water loss were also seen. These changes were associated with decreases in urinary cAMP. Inner medullary collecting duct (IMCD) cells were removed from these animals and were stimulated with graded doses of vasopressin. Cells from cisplatin-treated rats showed an impaired response in cAMP generation to vasopressin stimulation as compared to cells from normal animals. To determine more precisely the site of impairment, the adenylate cyclase complex of the IMCD cells was further studied with forskolin and NaF. Forskolin was used to probe the catalytic unit activating adenylate cyclase, and NaF the guanine nucleotide regulatory protein (G protein). In response to forskolin, cells from cisplatin-treated rats and normal rats responded similarly in generating cAMP. However, following NaF, the cAMP response was blunted in the cells from the cisplatin rats. These results suggested that the catalytic unit was not injured by cisplatin (forskolin study) but the G protein was (NaF). In conclusion, the present study suggests that the polyuria seen following cisplatin administration is associated with an end-organ resistance to vasopressin manifested by reduced cAMP generation, secondary in part or whole to a defect at the level of the G protein.

Cellular mechanism of lithium-induced nephrogenic diabetes insipidus in rats

One of the mechanisms by which Li evokes polyuria is thought to be impairment of arginine vasopressin (AVP)-sensitive adenylate cyclase (AdC) in cells of the renal collecting duct. To investigate how AdC is influenced by chronic administration of Li, we created nephrogenic diabetes insipidus (NDI) in rats and microdissected the medullary collecting tubule from both control and NDI rats. In the NDI group, the 10(-6) M AVP-stimulated cAMP contents failed to increase completely, and the levels were significantly lower than that of the control group (10.4 +/- 1.4 vs. 48.4 +/- 4.7 fmol/mm, P less than 0.001). Pretreatment with pertussis toxin (PT), an inhibitor of inhibitory G protein (Gi), did not affect the basal cAMP levels in both groups, although it increased AVP-stimulated cAMP production in the NDI group in a dose- and time-dependent manner. AVP-stimulated cAMP production with over 100 ng/ml PT in the NDI group reached the levels observed in the control group. Incubation with cholera toxin, an agonist of stimulatory G protein (Gs), increased the cAMP content in the two groups to almost equal levels. To exclude the possibility that prostaglandin E2 (PGE2) is involved in the cellular mechanism of Li-induced NDI, the effect of indomethacin (Indo) on PT action was examined. However, Indo (10(-5) M) did not influence either the basal or AVP-dependent cAMP contents. From these results it is suggested that Li impairs AVP-sensitive AdC not through inhibition of Gs but through activation of Gi and that PGE2 may not be involved in the cellular pathogenesis of NDI at least in the rat at the step of cAMP formation.

Splenectomy attenuates the inappropriate diuresis associated with tumor necrosis factor administration

Tumor necrosis factor (TNF) is an important mediator of the systemic response to gram-negative sepsis and endotoxemia. We studied the renal effects of a sublethal TNF infusion in dogs (0.54 = 10(5) international units per kilogram of body weight during a six hour period). The TNF-infused dogs (n = 4) had marked polyuria and natriuresis in comparison with those in the control group (n = 12) (urine output, 35.3 +/- 4.1 versus 3.7 +/- 0.5 millimeters per kilogram per six hours p less than 0.01; sodium excretion, 2.82 +/- 0.27 versus 0.75 +/- 0.19, p less than 0.01). To evaluate the role of the spleen in this response, seven dogs that had splenectomy were infused with TNF. Splenectomy abolished both the polyuria and the natriuresis; this could not be explained by the differences in fluid balance or in hemodynamic or metabolic alterations. Treatment with ibuprofen given intravenously (12.5 milligrams per kilogram 40 minutes before and three hours after the beginning of TNF infusion) in eight dogs that did not undergo splenectomy also abolished these renal effects. Prostaglandin 2 (PGE2) concentrations in selected blood samples from the splenic vein did not increase with TNF infusion, excluding circulating PGE2 as a possible mediator of the renal effects. The results of these studies indicate that, during septic challenge or severe inflammation, the spleen participates in signaling the kidney to increase water and sodium excretion. These renal events are mediated through the cyclo-oxygenase pathway.

Changes of lithium elimination in acute polyuric renal failure caused by cisplatin and mercuric chloride

Changes in lithium elimination were studied under the condition of experimentally induced polyuric acute renal failure by cisplatin (6 mg/kg body wt) or HgCl2 (3 mg/kg body wt). The histologically proven lesions of tubuli were associated with the decrease of plasma clearance of lithium (C(Li)) and polyfructosan-S (CP(FS). The decrease of these clearance values was not proportional and the ratio C(Li)/CP(FS) (indicating renal fractional excretion of Li+) increased significantly (p less than 0.01). The increase of C(Li)/CP(FS) was related to the increase of renal fractional sodium excretion (FENa) (p less than 0.01). The results suggest that the impairment of tubular cells by cisplatin or HgCl2 caused the decrease of tubular reabsorption of Li+ and Na+. From the pharmacokinetic point of view, these experiments suggest that changes in tubular transport of drugs should be taken into account in their dosing adjustment in patients with acute polyuric tubular lesion.

Maternal lithium therapy and polyhydramnios

Lithium is widely used in the treatment of bipolar affective disorders, and teratogenic effects include cardiovascular abnormalities, notably Ebstein anomaly. The most common side effect in the patient taking lithium is polyuria, a form of nephrogenic diabetes insipidus. We report the case of a manic-depressive gravida on lithium therapy who developed polyhydramnios in her last trimester. Because lithium crosses the placenta, we postulate that, by a similar mechanism, lithium may cause fetal polyuria which results in polyhydramnios.

["Munchausen syndrome by proxy" as an example of diagnostic error]

A case of the girl who underwent multiple hospitalizations is presented. Gastrointestinal disorders were seen in the infancy together with skin rash of allergic type, hypoglycaemia without any clear reason in the fourth year of age, and polyuria with hyponatremia and hypokalemia since the sixth year of age. Mother's lack of concern was unexplainable in view of the deteriorating child's health. Samples of the urine and faeces supplied by the mother have shown the laboratory findings suggesting that potassium chloride was added to the faeces and natrium hydrocarbonate--to the urine. Urine collected during polyuria contained large quantities of furosemide. Long-term follow-up, numerous examinations and performed tests have led to the diagnosis of the particular form of the ill-treated child syndrome, so-called "Munchausenn by proxy" syndrome.

Adverse effects of gentamicin in scarlet macaws and galahs

The adverse effects of administration of gentamicin (5 mg/kg of body weight, IM, q 12 h) for 7 days were studied in healthy scarlet macaws (Ara macao) and galahs (Eolophus roseicapillus; cockatoos). Polydipsia and polyuria developed in each species, but were greater and persisted longer in the cockatoos. Peak water intake in the cockatoos more than quadrupled, and remained increased for 23 days after cessation of gentamicin administration. Plasma aspartate transaminase activity increased significantly (P less than 0.05) after treatment in the macaws, and plasma aspartate transaminase and lactate dehydrogenase activities increased in the cockatoos. Single IM administration of gentamicin (5 mg/kg) resulted in mean (+/- SEM) plasma concentration of 20.6 (+/- 1.85) micrograms/ml at 0.5 hour for either species of birds. There were no significant differences between mean plasma gentamicin concentrations for cockatoos and macaws at any time after drug administration, except at 12 hours, when values for cockatoos were significantly (P less than 0.05) greater than those for macaws. The elimination half-life for gentamicin after IM administration of 5 and 10 mg/kg was 1.17 and 1.07 hours, respectively, for macaws and 1.23 and 1.44 hours, respectively, for cockatoos. Correlation between drug disposition and adverse side effects could not be detected.

[Nephrogenous diabetes insipidus caused by amphotericin B]

A patient on systemic amphotericin B therapy developed polyuria with low osmolarity of the urine probably due to nephrogenic diabetes insipidus. This rarely reported side effect of amphotericin B appears not to necessitate discontinuation of the treatment provided adequate fluid intake can be guaranteed. The diabetes insipidus is reversible in 2-6 months after cessation of the treatment: in our patient the polyuria and the low urine osmolarity disappeared within a few days.

Lack of a modifying effect by the diuretic drug furosemide on the development of neoplastic lesions in rat two-stage urinary bladder carcinogenesis

The effect of the diuretic drug furosemide on two-stage urinary bladder carcinogenesis in F344 rats initiated by N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) was investigated with regard to possible promoting activity. BBN was administered at 2 doses, 0.01 or 0.05%, in drinking water for 4 wk, and thereafter furosemide was given by gavage 3 times weekly for 32 wk, 250 mg/kg body weight. Furosemide ingestion induced diuresis with an alkaline, hypotonic urine. No significant difference with regard to incidences of bladder lesions were apparent between furosemide and control groups. The present investigation indicated that neither furosemide nor its related polyuria acted as a promoter in two-stage urinary bladder carcinogenesis.

Renal concentration defect induced by cisplatin. The role of thick ascending limb and papillary collecting duct

The effects of cisplatin (5 mg/kg BW given intraperitoneally) on renal concentration mechanism were evaluated initially by clearance studies in rats 5-7 days after cisplatin administration and compared to normal rats. During hypotonic saline infusion, cisplatin rats showed a lower inulin clearance (0.56 +/- 0.07 vs. 1.12 +/- 0.09 ml/min/100 g BW, p less than 0.01), a higher fractional distal delivery (CNa + CH2O/Cin) (36.3 +/- 4.4 vs. 22.8 +/- 4.5%, p less than 0.05), and lower CH2O/CNa + CH2O (33.6 +/- 5.8 vs. 56.5 +/- 5.0%, p less than 0.01). During hypertonic saline infusion the TcH2O/Cosm was lower in cisplatin (18.3 +/- 1.1%) than in normal rats (33.4 +/- 3.5%, p less than 0.01). These results suggest a defect in NaCl transport in the thick ascending limb of Henle and proximal tubule. In order to characterize these tubular defects, we measured Na-K-ATPase activity (microM Pi/mg protein/h). In the renal cortex of cisplatin rats the ATPase activity was lower (18.1 +/- 3.2) than in normal rats (33.4 +/- 6.4, p less than 0.05), also in the inner strip of the outer medulla of cisplatin rats Na-K-ATPase was reduced (26.0 +/- 5.7) when compared with normal rats (67.3 +/- 9.2, p less than 0.01), presumably representing a decrease in enzyme activity in the thick ascending limb.(ABSTRACT TRUNCATED AT 250 WORDS)

Lithium, polyuria and abnormal diurnal weight gain in psychosis

We evaluated diurnal weight gain and polyuria among 31 institutionalized chronically psychotic patients receiving lithium and 42 controls not receiving this drug. The patients were weighed weekly for three weeks at 7 a.m. and 4 p.m. We normalized the diurnal weight gain (NDWG) as a percentage by subtracting the 7 a.m. weight from the 4 p.m. weight, multiplying the difference by 100, and then dividing the result by the 7 a.m. weight. Polyuria was assessed using mean urine creatinine concentration (MUCR). NDWG was abnormal among study patients (1.9 +/- 1.2%) and controls (1.6 +/- 1.5%) independent of lithium treatment. The variation in MUCR explained about 20% of the variation in NDWG in both groups.

Lithium-induced morphological changes in the rat kidney at different levels of urine flow

Lithium treated rats become polyuric and at the same time develop pronounced dilatations of distal tubular segments and characteristics enzyme histochemical changes. In the present study we have compared lithium-polyuric Wistar rats with lithium treated rats in which the polyuria was prevented either by administration of a vasopressin analogue or by water restriction. The kidneys were studied using enzyme histochemistry and light microscope morphometry. The characteristic lithium induced changes were present in all groups irrespective of the presence or absence of polyuria. It is concluded therefore, that the morphological and enzyme histochemical changes are induced by the lithium ion per se and not by the accompanying polyuria.

Neonatal treatment with vasopressin antagonist dP[Tyr(Me)2]AVP, but not with vasopressin antagonist d(CH2)5[Tyr(Me)2]AVP, inhibits body and brain development and induces polyuria in the rat

Two vasopressin antagonists, d(CH2)5[Tyr(Me)2]AVP and dP[Tyr(Me)2]AVP, were given to Wistar rats from postnatal day 1 to 21 in order to investigate the influence on development and later diuresis. The latter antagonist significantly reduced body growth from day 3 postnatally onwards. At postnatal day 35 body, total brain, cerebellar and kidney weights were significantly reduced compared with controls. Diuresis, measured at one month of age, was four- to five-fold higher than the control group. Combined treatment with vasopressin failed to abolish the weight disturbances or polyuria. However, animals treated with the vasopressin antagonist d(CH2)5[Tyr(Me)2]AVP did not show developmental or diuretic deficits. Allometric analysis of brain/body relationship of the young animals indicated a disturbance of brain development by dP[Tyr(Me)2]AVP. Although the body and brain growth retardation induced by dP[Tyr(Me)2]AVP supports the hypothesis of a role for vasopressin in brain ontogeny, it can also be the result of a nonAVP-related toxic effect, since it could not be prevented by concomitant treatment with vasopressin.

Involvement of prostaglandin E2, cAMP, and vasopressin in lithium-induced polyuria

The involvement of prostaglandin E2 (PGE2), adenosine 3',5'-cyclic monophosphate (cAMP), and vasopressin in lithium-induced polyuria was investigated in rats. Administration of LiCl (4 mmol/kg body wt) for 7 days induced a marked polyuria with a significant excretion of urinary PGE2. Administration of indomethacin (IND, 5 mg/kg body wt) for 4 days to lithium-induced diabetes insipidus (LiDI) rats diminished urine volume by 80% and urinary PGE2 by 85%. The in vitro data of the intact rat kidney showed that lithium stimulated arginine vasopressin (AVP)-induced PGE2 production and suggested that PGE2 suppressed cAMP synthesis in rat renal medulla. The AVP-induced PGE2 synthesis was greater and the AVP-stimulated cAMP production lower in the LiDI rat kidney in vitro. Interference of the vasopressin-associated cAMP system and the increased PGE2 synthesis in the kidney may be involved in the development of LiDI. The reduced cAMP production in the LiDI rat kidney might be partly due to the increased PGE2 synthesis. In LiDI rats plasma vasopressin increased, whereas AVP concentration in the hypothalamus and the neurohypophysis significantly decreased. It is postulated that lithium stimulates vasopressin release from the central nervous system and that elevated plasma vasopressin potentiates PGE2 production in the kidney synergistically with lithium.