Effects of lithium on the kidney

Lithium carbonate: Updated reproductive and developmental toxicity assessment using scientific literature and guideline compliant studies

The current publication describes most recent so far unpublished (key) guideline and GLP compliant reproductive and developmental toxicity studies of lithium carbonate in rats, including their interpretation and conclusions in terms of human hazard assessment when compared to existing literature. Particular attention was paid to the target organs and dose response of lithium ion related effects to differentiate between a primary (pharmacokinetic/pharmacodynamic) action and secondary effects as a result of systemic and target organ toxicity. In the key two-generation reproduction toxicity (OECD TG 416) study in rats, doses of 5, 15 and 45 mg/kg bw/d (0.95, 2.9 and 8.6 mg Li⁺/kg bw/d) were given by oral gavage, resulting in clear NOAELs of 15 mg/kg bw/d (2.9 mg Li⁺/kg bw/d) for systemic parental toxicity and 45 mg/kg bw/d (8.6 mg Li⁺/kg bw/d) for reproductive toxicity and fetal toxicity. Target organ changes were consistently observed in liver (cytoplasmic rarefaction) and kidney (dilated tubuli). In the key developmental toxicity (OECD TG 414) study in rats, doses given by oral gavage were 10, 30 and 90 mg/kg bw/d (1.9, 5.7 and 17.1 mg Li⁺/kg bw/d) was investigated resulting in NO(A)ELs of 30 mg/kg bw/d (5.7 mg Li⁺/kg bw/d) (maternal toxicity) and 90 mg/kg bw/d (17 mg Li⁺/kg bw/d) (fetal toxicity and teratogenicity). The highest dose of 90 mg/kg bw/day resulted in clear signs of toxicity and peak plasma concentrations at the toxic range (>1.0 mEq lithium/L). Toxic effects of lithium carbonate were not seen in the reproductive and developmental organs. No adverse effects on sperm (total motility, progressive motility and morphology of testicular and cauda epididymal sperm) were observed in the two-generation rat reproduction toxicity study. There was also no impact on fertility indices or on litter sizes in this study, nor were there any fetal effects in the two-generation reproduction toxicity and developmental toxicity study at doses causing already systemic toxicity in the dams. Secondary effects such as decreased weight (gain) and food consumption were reported in the developmental toxicity study. The absence of any reproductive/developmental findings at dose levels causing clear systemic toxicity in the test animals in these key mammalian studies, does not suggest an immediate concern for possible human reproductive or developmental toxicity effects from exposure to lithium during drug use.

Relationship between erythrocyte lithium concentration and renal concentrating capacity

BACKGROUND

Studies investigating possible correlations between plasma lithium concentration, lithium treatment duration, and frequency of lithium administration, and lithium nephrotoxicity have yielded conflicting results.

OBJECTIVES

Our main objective was to investigate whether there was any relationship between erythrocyte lithium concentration (ELC) and renal side effects. Another objective of our study was to identify a parameter, which could be estimated inexpensively, for assessing possible renal side-effects of lithium.

METHOD

Seventy Iranian inpatients with bipolar disorder entered this case-control study. Medications taken concurrently by the patients were recorded. A direct method of measuring ELC was used in this study. The cases were patients on lithium who had urine specific gravity (SG) of 1.006 or less after 8-10 h water deprivation at night and the controls consisted of patients on lithium with urine SG of 1.011 or more after this period. Blood urea nitrogen, serum creatinine, sodium and potassium and urine SG, sodium, and potassium were measured in all patients during this time. Renal indices were compared by using independent sample t-test at a significance level of a P-value of 0.05 or less. Non-parametric Spearman's rank correlation test was used to investigate the relationship between clinical variables and the indices of renal function.

RESULTS

Results revealed that in case group mean serum sodium concentrations were significantly higher (P = 0.008) and mean urine sodium and potassium were significantly lower than those of controls (P = 0.004 and 0.007 respectively). We found no statistically difference in lithium ratios between the two groups. However, ELCs were significantly higher in the cases (P = 0.026). There were no significant correlation between concomitant use of neuroleptics, benzodiazepines or carbamazepine and ELC or lithium renal side-effects.

CONCLUSION

This study showed that ELC may reflect lithium renal side-effects better than plasma lithium level.

The trace elements in response to lithium intoxication in renal failure

The polyuric syndrome that develops as a consequence of chronic administration of lithium salts is most frequent and often causes complication in the treatment of manic depressive disease with the administration of drugs. It is known that kidneys play an essential role in systematic depositing of toxic metals. The purpose of this study was not only the determination of dose-dependent lithium concentration in serum and urine but also an estimation of sensitive biochemical indicators of nephrotoxicity detectable at an early stage after the administration of lithium carbonate to rats. Animals were given orally lithium salt to female Wistar rats at the dose of 10 and 20mg Li/kg daily during 5 weeks. In the urine diuresis protein concentration, copper, zinc, lithium and N-acetyl-beta-glucoaminidase (NAG) activity were determined. In the serum also lithium, copper and zinc were analyzed. The results of the experiments indicate that the changes in urinary concentrations of essential copper, proteins, NAG activity and diuresis were observed when the concentration of lithium was ca. 9.79+/-1.68 mmol Li/L and in serum it corresponded to 0.3+/-0.06 mmol Li/L. These values corresponded to total doses of 150 mg Li/kg body weight administered to rats. In summary the increase of copper concentration, diuresis and urinary concentrations of protein and the NAG activity may be interpreted as a general metabolic response of kidneys induced by lithium detectable as an earlier indicator of nephrotoxicity. Therefore, regular determinations of lithium concentrations in serum of patients are important tools in the prevention of intoxication.

Case report and review of the perinatal implications of maternal lithium use

The purpose of this study was to review the use of lithium in pregnancy and its effects on the neonate. This was a case study and review of the published literature. Lithium is commonly used in the treatment of psychiatric disorders, specifically bipolar depression. Bipolar disorders that require treatment with lithium demand special consideration when the woman becomes pregnant. Reported neonatal problems with maternal lithium therapy include Ebstein's anomaly, poor respiratory effort and cyanosis, rhythm disturbances, nephrogenic diabetes insipidus, thyroid dysfunction, hypoglycemia, hypotonia and lethargy, hyperbilirubinemia, and large-for-gestational-age infants. Lithium can have adverse effects on the fetus and newborn infant, but data suggest normal behavioral patterns in childhood.

Mechanism of lithium-induced polyuria in the rat

While many studies have demonstrated a nephrogenic diabetes insipidus syndrome (NDI) with prolonged lithium (Li) treatment, experiments in the isolated rat papillary collecting duct have suggested that the defect may be due to a circulating factor that inhibits the action of arginine vasopressin (AVP). Since Li-treatment can produce a form of hyperparathyroidism and parathyroid hormone (PTH) can act as a partial agonist to AVP, in vivo and in vitro studies were performed on rats made polyuric by daily intraperitoneal (i.p.) Li (4 mmol/kg) treatment. Li-treatment for three weeks produced an increase in PTH (194 +/- 20 compared with 118 +/- 18 pg/ml in control rats; P < 0.01) as well as an increase in the plasma calcium concentration (2.38 +/- 0.05 compared with 2.25 +/- 0.04 mmol/liter; P < 0.05). Clearance studies were performed on water loaded Li-treated and control rats, and the defect in urine concentration was only observed with a low physiological concentration of AVP (10 mU/kg body wt over 5 min). Maximal urine osmolality was 328 +/- 31 compared with 613 +/- 81 mOsm/kg (P < 0.05) in controls. There was no detectable difference with a prolonged maximal physiological AVP concentration (10 mU bolus and 50 mU/kg body wt per hr) and papillary solute concentrations were unchanged. When Li-treated rats had been parathyroidectomized (PTX), a significant difference in urine concentration with the low AVP concentration could not be demonstrated when compared to non-PTX control rats. In the isolated papillary collecting duct preparation a medium was used that contained fresh plasma from Li-treated or control rats, both intact and PTX. Experiments using plasma from Li-treated intact rats produced only a 25.4 +/- 5.1% increase in diffusional water permeability with the addition of AVP (200 microU/ml) compared to 52.6 +/- 9.0% in control rats (P < 0.01). However, when plasma from Li-treated PTX rats was used, the AVP induced increase in water permeability (54.7 +/- 11.2%) was not significantly different from that observed in PTX control rats. These studies show that the NDI-like defect in Li-treatment is small and easily overcome by higher concentrations of AVP and suggests that the concentration defect is at least in part due to increased circulating levels of PTH acting as a partial agonist to AVP and thereby inhibiting its hydroosmotic action.

When should dialysis be performed in lithium poisoning? A kinetic study in 14 cases of lithium poisoning

Lithium kinetics were studied in 14 patients with lithium poisoning. Three patients were treated by hemodialysis. Serum lithium peak concentrations ranged between 1.4 and 9.6 mmol/L. The apparent mean serum half-life was 23.16 +/- 9 h, the mean total clearance was 26.5 +/- 13.3 mL/min and the mean renal clearance was 17.2 +/- 5.4 mL/min. The kinetic parameters were dependent on the duration of the study and on the type of the poisoning: acute, acute upon chronic or chronic. During the first 12 h after admission ten patients were in a distribution phase, three were in an elimination phase and one was in an absorption phase. The serum half-life during hemodialysis ranged from 3.6 to 5.7 h and hemodialysis clearance was 63.2 to 114.4 mL/min. The mean volume of distribution calculated in six cases was 0.63 +/- 0.09 L/kg. The evolution of the lithium pools showed a different kinetic pattern between the extra- and the intracellular pool which decreased more slowly. During hemodialysis the decrease of the extracellular pool was about twice that of the cellular pool. Among the factors which may modify lithium toxicity and kinetics, are the type of the poisoning, the presence of an underlying disease and renal impairment. No general and rigid indication for hemodialysis can be set, but the need for hemodialysis should be based on clinical and kinetic data determined during the 12 h following admission.

Lithium does not alter the renal response to a pressor dose of tyramine in man

Renal clearance of lithium has been used as a marker of proximal tubular function in man. Recently, lithium pre-treatment has been shown to interfere with the natriuretic actions of some natriuretic agents in man. We have therefore investigated the effects of oral lithium carbonate (500 mg) on the natriuretic response to a pressor dose of tyramine (15 micrograms kg-1 min-1) in six normal volunteers. Lithium had no effect on baseline sodium excretion, nor did it affect the tyramine-induced increase in blood pressure and subsequent natriuresis. These results show that oral lithium carbonate (500 mg) does not appear to interfere with the pressure natriuretic response to tyramine in man.

Lithium intoxication with acute renal failure and death

A 65-year-old female presented with only gastrointestinal symptoms eight to ten hours after an acute ingestion of an unknown amount of lithium carbonate. The serum lithium concentration was 8.5 mEq/L. Forty-eight hours postingestion she developed acute renal failure, deteriorating mental status, and cardiovascular collapse. Despite both hemodialysis and peritoneal dialysis the patient died approximately four and one-half days after ingestion. A direct nephrotoxic effect of lithium is proposed.

The effect of lithium on the renal response to the dopamine prodrug gludopa in normal man

1. The effect of oral lithium on the renal response to gamma-L-glutamyl-L-dopa (gludopa, 25 micrograms kg-1 min-1) was investigated in seven normal males. 2. Gludopa at this dose produced an 800-fold increase in urine dopamine excretion. It was natriuretic and suppressed plasma renin activity without altering blood pressure and pulse. 3. Lithium alone increased sodium excretion and stimulated plasma renin activity. However, it abolished the natriuresis produced by gludopa. 4. Gludopa did not significantly affect lithium clearance. 5. This study suggests that lithium interacts with dopamine at the proximal tubule and that the lithium clearance method is not suitable for investigating dopaminergic mechanisms in the kidney.

Prevalence, pathogenesis, and treatment of renal dysfunction associated with chronic lithium therapy

From the analysis of several studies published from 1979 to 1986 comprising 1,172 patients, we estimated that glomerular filtration rate (GFR) was normal in 85% of unselected patients on chronic lithium therapy. The remaining 15% of patients displayed only mild reduction in GFR, clustering at approximately 60 mL/min. Thus, the data available to date do not support earlier concerns that long-term lithium therapy could eventuate into renal insufficiency. The most prevalent renal effect of lithium is impairment of concentrating ability, which we estimated to be present in at least 54% of 1,105 unselected patients on chronic lithium therapy. This defect translated into overt polyuria in only 19% of unselected cases. A renal lesion confined to the collecting tubule has been described in humans who have taken lithium for short periods of time. This lesion may represent the collecting tubule's response to the intracellular accumulation of lithium, which interferes with cAMP formation and results in an early and probably reversible inhibition of antidiuretic hormone (ADH)-mediated water transport. However, long-term lithium therapy may induce a progressive and partly irreversible defect in concentrating ability. The potential risk for dehydration associated with lithium-induced polyuria, as well as the discomfort inherent to this side effect, deserves evaluation and consideration for therapeutic intervention. Amiloride has additional advantages over conventional treatment of nephrogenic diabetes insipidus using thiazide diuretics. The action of amiloride on ADH-mediated water transport seems specific in as much as it is capable of preventing the uptake of lithium in high resistance epithelia and thereby prevents the inhibitory effect of intracellular lithium on water transport. Unlike thiazides, amiloride has a weak natriuretic effect and is less likely to increase plasma lithium levels by causing volume contraction. In addition, amiloride, by conserving potassium, obviates the need for potassium supplementation that is usually required to prevent hypokalemia when thiazides are used to treat lithium-induced polyuria. Since amiloride may prevent chronic intracellular lithium accumulation in the collecting tubule, future studies should elucidate whether amiloride also has a role in preventing lithium-induced chronic tubulo-interstitial damage.

Self-poisoning and therapeutic intoxication with lithium

Of 68 admissions for lithium overdose over 16 years, 25 were due to therapeutic intoxication and 43 to deliberate self-poisoning. Three patients with therapeutic intoxication had acute diabetes insipidus with hypernatraemia. One of them had acute renal failure requiring dialysis, prolonged Parkinsonism and generalised myopathy. Twenty-two patients with therapeutic intoxication had peak serum lithium concentrations above the therapeutic range. In contrast, of 22 self-poisoned patients with peak serum lithium concentrations above the therapeutic range only 3 developed toxicity. The mean admission plasma urea concentration in patients with therapeutic intoxication was higher than in self-poisoned patients and the mean admission plasma bicarbonate concentration was lower. The mean serum lithium half-life in 8 patients with therapeutic intoxication was considerably longer than in 5 self-poisoned patients. Renal lithium clearance is enhanced by increased sodium excretion and we recommend that lithium toxicity be treated with saline diuresis and frusemide if fluid retention occurs. Haemodialysis is mandatory when renal failure is present, and may be indicated when serum lithium concentrations are very high or rising rapidly.

Myocardial changes in rats with lithium-induced uraemia

The possible effects of lithium on myocardial morphology were studied at the light-microscopic level in three different rat models: (i) rats with chronic renal failure due to lithium administration for 8-16 weeks after birth, (ii) normal, adult rats treated with lithium for 16 weeks, and (iii) new-born rats exposed to lithium in their prenatal life. Morphological changes were found in 57% of the male rats with lithium-induced uraemia after lithium administration for 16 weeks postnatally. The changes comprised myocytic degeneration and necrosis associated with infiltration of lymphocytes, histiocytes and plasma cells. This morphological picture is different from the myocardial changes associated with chronic renal failure. Male rats with chronic uraemia after withdrawal of lithium 8 weeks postnatally showed no myocardial changes after 16 weeks. Also, male rats with normal renal function had no myocardial changes after 16 weeks on lithium, but these rats had a significantly lower plasma level of lithium than the lithium-uraemic rats (0.8 vs. 1.4 mmol/l). It is suggested that myocarditis was a consequence of persistent high plasma levels of lithium maintained in the lithium-uraemic rats and that cardiotoxic effects of lithium may be potentiated by concomitant renal failure.

Side-effects of lithium at lower therapeutic levels: the significance of thirst

The prevalence of thirst, subjective polyuria and related side-effects was investigated in 87 patients attending a lithium clinic and in a group of 52 controls. Thirst was surprisingly common, occurring in 67% of patients, in spite of the fact that they had been maintained on relatively low levels of lithium, and was due principally to the lithium rather than to other psychotropic drugs. Urine flow and impaired renal water absorption correlated with the serum lithium level and the length of treatment in the patients, despite the fact that few were clinically polyuric. The pattern of the results confirms previous suggestions that lithium may stimulate the thirst mechanism directly as well as via an increased renal resistance to vasopressin. The possible implications in terms of clinical response are discussed.

Effects of lithium on electrical activity and potassium ion distribution in the vertebrate central nervous system

Three different regions of the vertebrate central nervous system maintained in vitro (frog spinal cord, guinea pig olfactory cortex and hippocampus) have been used to investigate how Li+ influences membrane potential, membrane resistance, action potentials, synaptic potentials and the transmembrane K+-distribution of neurons and glial cells. In view of the therapeutic action of Li+ in manic-depressive disease, a special effort was made to determine the threshold concentration for the actions of Li+ on the parameters described above. It was observed that Li+ induced a membrane depolarization of both neurons and glial cells, a decrease of action potential amplitudes, a facilitation of monosynaptic excitatory postsynaptic potentials and a depression of polysynaptic reflexes. The membrane resistance of neurons was not altered. Li+ also induced an elevation of the free extracellular potassium concentration and a decrease of the free intracellular potassium concentration. Furthermore, in the presence of Li+ a slowing of the recovery of the membrane potential of neurons and glial cells, and of the extracellular potassium concentration after repetitive synaptic stimulation was observed. The threshold concentrations for the effects of Li+ were below 5 mmol/l in the frog spinal cord and below 2 mmol/l in the guinea pig olfactory cortex and hippocampus. The basic mechanism underlying the action of Li+ may be an interaction with the transport-function of the Na+/K+ pump.

Drug prescribing in renal failure: dosing guidelines for adults

The data base for rational guidelines to safe, efficacious drug prescribing in adults with renal insufficiency are presented in tabular form. Current medical literature was extensively surveyed to provide as much specific information as possible. When information is lacking, however, recommendations are based on pharmacokinetic variables in normal subjects. Nephrotoxicity, important adverse effects, and special considerations in renal patients are noted. Adjustments are suggested for hemodialysis and peritoneal dialysis when appropriate.

The mechanism of polyuria in rats pretreated with lithium studies by in vitro microperfusion

The collecting ducts in papillae taken from normal rats have a measurable increase in diffusional tritiated water (THO) permeability with ADH 5 mu unit/ml and this increase is maximal with antidiuretic hormone (ADH) 100 mu unit/ml added to media. The presence of plasma from rats pretreated with lithium to make them polyuric inhibited the response to ADH. The lowest concentration of ADH that caused a measurable increase in diffusional water permeability was 50 mu unit/ml and the increase was maximal with ADH 2000 mu unit/ml. The maximum response to ADH did not differ whether plasma from control or lithium pretreated rats was used. However, the dose-response curve to ADH was shifted to the right by the plasma from lithium-pretreated rats. Lithium added to the plasma from control rats did not alter the response to ADH. It is proposed that lithium given to rats causes a circulatory factor to be produced that inhibits in a competitive fashion the response of the collecting duct to ADH. Such an effect would explain many features of the impairment of water excretion associated with lithium use.

Kidney tubule cell injury of male rats after estrogen treatment

Ultrastructural changes in the tubular epithelium of the rat kidney following a large dose of estrogen (300 micrograms per week for 20 weeks) were studied by means of electron microscopy. The ultrastructural changes in estrogen-treated rats were confined to the proximal tubule. The changes consisted of intracytoplasmic vacuoles and dilatation of the intracellular space between adjacent tubule cells. The cisternae of the endoplasmic reticulum exhibited some degree of vesiculation characterized by club-like formations. In addition, large masses of collagen could be observed within the peritubular capillaries. In contrast to the controls the tubular cells of estrogen-treated rats exhibited large areas or granules with dense inclusions and membranous, filamentous material in a process of being transformed into an autolysosome and residual body. The results are discussed in the light of those of other authors.

Severe functional and structural changes caused by lithium in the developing rat kidney

Lithium (Li) was administered to rats during maternal pregnancy and/or 8 weeks post-natally, to study the effects on renal function and structure in the developing kidney. Plasma Li was 0.5-1.0 mmol/l 3 and 8 weeks post-natally. Functionally, post-natal Li leads to growth retardation, polyuria with lowering of renal concentration ability, and uremia associated with as much as 80% lowering of the normal glomerular filtration rate (GFR). Pre-natal Li alone did not affect the concentrating ability but caused a 20% increase in GFR when evaluated 8 weeks post-natally. Post-natal Li caused very severe structural changes, consisting of up to 3 mm cortical cysts (= dilated distal convoluted tubules), extensive interstitial fibrosis with cell infiltration, and atrophy of the cortical collecting ducts. Morphometric measurements showed a significant reduction in the volume of the proximal tubular cells. Pre-natal Li caused only slight structural changes, and animals treated both pre- and post-natally were less affected than animals treated post-natally only. The structural changes caused by post-natal Li were unrelated to changes in the concentrating ability but showed a significant correlation with the lowering of the GFR. It is concluded that the post-natally developing rat kidney is particularly sensitive to the nephrotoxic effects of Li, which in low concentrations causes impairment of renal function, leading to uremia. Pre-natal Li exposure by maternal lithium treatment had little effect on renal function and structure when evaluated post-natally.

Disorders of urinary concentration and dilution

A new approach to the classification of disorders of urinary concentration and dilution is recommended based on recent studies of how the kidney elaborates a urine of widely varying osmolality. The capacity to concentrate urine depends on ft, the fractional reabsorption of solute delivered to the loop of Henle; fu, the excretion of solute relative to the sum of solute excretion and solute delivery to Henle's loop; fw, the fraction of solute loss by vascular outflow from the medulla relative to that reabsorbed by the loop; and finally, collecting duct response to antidiuretic hormone (ADH). A decrease in ft or in increased fu or fw will diminish urinary concentrating ability, as will resistance of the tubule to ADH. Conversely, urinary dilution depends on the delivery of sodium and water to the ascending limb; NaCl reabsorption by the ascending limb; and the absence of ADH. A decrease in sodium and water delivery to the ascending limb or in NaCl reabsorption by the ascending limb will impair urinary diluting ability, as will the presence of ADH. The consequences of disorders in urinary concentrating and diluting ability vary widely. In an alert patient with an intact thirst center, there may be no consequence; in a patient unable to communicate thirst or whose thirst center is deranged, the results may be catastrophic. Keeping in mind the kidney's few basic requirements for formation of concentrated or dilute urine may help the physician avoid these potentially serious dislocations of water balance.