The impact of environmental temperature on lithium serum levels

A Review for Lithium: Pharmacokinetics, Drug Design, and Toxicity

Lithium as a mood stabilizer has been used as the standard pharmacological treatment for Bipolar Disorder (BD) for more than 60 years. Recent studies have also shown that it has the potential for the treatment of many other neurodegenerative disorders, including Alzheimer's, Parkinson's and Huntington's disease, through its neurotrophic, neuroprotective, antioxidant and anti-inflammatory actions. Therefore, exploring its pharmacokinetic features and designing better lithium preparations are becoming important research topics. We reviewed many studies on the pharmacokinetics, drug design and toxicity of lithium based on recent relevant research from PubMed, Web of Science, Elsevier and Springer databases. Keywords used for searching references were lithium, pharmacology, pharmacokinetics, drug design and toxicity. Lithium is rapidly and completely absorbed from the gastrointestinal tract after oral administration. Its level is initially highest in serum and then is evidently redistributed to various tissue compartments. It is not metabolized and over 95% of lithium is excreted unchanged through the kidney, but different lithium preparations may have different pharmacokinetic features. Lithium has a narrow therapeutic window limited by various adverse effects, but some novel drugs of lithium may overcome these problems. Various formulations of lithium have the potential for treating neurodegenerative brain diseases but further study on their pharmacokinetics will be required in order to determine the optimal formulation, dosage and route of administration.

Plasma Lithium Levels in a General Population: A Cross-Sectional Analysis of Metabolic and Dietary Correlates

Initial evidence suggests that lithium might affect life expectancy and the risk for different disease conditions, but most studies were conducted in patients on lithium medication. Little is known about the association of blood lithium levels within the physiological range with cardiometabolic risk factors and diet. We measured plasma lithium in a community-based sample from Northern Germany (samples taken between 2010 and 2012). All participants (aged 25-82 years) underwent standardized examinations and completed a semi-quantitative food frequency questionnaire. Of several variables tested, the estimated glomerular filtration rate (eGFR) was statistically significantly (inversely) associated with lithium levels, mainly in individuals with slightly impaired renal function (eGFR < 75 mL/min/1.73 m²). Besides, lithium levels were positively associated with age and alcohol intake. Using reduced rank regression, we identified a dietary pattern explaining 8.63% variation in plasma lithium levels. Higher lithium levels were associated with higher intakes of potatoes, leafy vegetables, root vegetables, fruits, tea, beer, wine and dietetic products and lower intakes of pasta, rice, pork, chocolate, sweets, soft drinks, other alcoholic beverages, sauces and snacks. Our observations suggest that plasma lithium levels are associated inversely with kidney function, particularly in individuals with slightly impaired renal function, and positively with age and alcohol intake. Lithium at physiological levels was moderately related to an exploratory dietary pattern.

Seasonal and temperature effect on serum lithium concentrations

BACKGROUND

Lithium remains the gold standard treatment for bipolar disorder. However, it has a very narrow therapeutic index (0.6-0.8 mmol/L). It has been suggested that high environmental temperature can lead to dehydration, elevated plasma lithium concentration and then lithium toxicity.

OBJECTIVES

We aimed to investigate the effect of seasonal and short-term changes in temperature on serum lithium concentrations in Sydney, Australia.

METHODS

We retrospectively analysed data from all patients who had serum lithium concentrations taken from the Prince of Wales and Sutherland Hospitals between 2008 and 2018. Temperature data came from the Bureau of Meteorology. We examined correlations between lithium concentrations and the preceding 5 days maximum temperatures, month and season. We also performed a longitudinal analysis of the effect of temperature and seasons within selected patients who had repeated levels.

RESULTS

A total of 11,912 serum lithium concentrations from 2493 patients were analysed. There was no significant association between higher lithium concentration and preceding higher temperatures (r = -0.008, p = 0.399). There was also no important seasonal or monthly variation, across all patients or in the smaller cohort with longitudinal data (n = 123, r = 0.008, 95% confidence interval: [-0.04, 0.06]).

CONCLUSION

There were no clinically important differences in serum lithium concentration related to seasons, months or temperatures, which suggests that patients on lithium are able to adequately maintain hydration during hot weather in Sydney.

Using Lithium in Older Age Bipolar Disorder: Special Considerations

Lithium is the gold-standard treatment for bipolar disorder, and is effective in the management of manic, depressive, and maintenance phases of bipolar disorder treatment. Despite this, the implications of lithium use in the older population remain less understood. This critical narrative review aims to better understand the impact of lithium in older age bipolar disorder (OABD), including tolerability and efficacy, based on up-to-date evidence. Relevant studies of efficacy, effectiveness, and tolerability published any time prior to May 2018 were identified using the PubMed keyword search "lithium older adult bipolar disorder" and references from recent international bipolar disorder guidelines. One randomized controlled trial was identified, the GERI-BD (Acute Pharmacotherapy in Late-Life Mania) study. This study found lithium to be effective in late-life mania and hypomania. The remaining literature examining lithium in OABD was reviewed, comprising of a number of small open-label and retrospective studies, with special considerations highlighted. In summary, there is a small yet increasing geriatric evidence base that lithium is effective in OABD. Although there can be adverse effects with lithium, it is generally well tolerated, and there are methods to minimize these risks. Further research would strengthen the evidence base for lithium therapy in OABD. In the meantime, lithium remains the gold-standard treatment for OABD.

Monitoring of patients treated with lithium for bipolar disorder: an international survey

Background

Adequate monitoring of patients using lithium is needed for optimal dosing and for early identification of patients with (potential) ADEs. The objective was to internationally assess how health care professionals monitor patients treated with lithium for bipolar disorder.

Methods

Using networks of various professional organizations, an anonymous online survey was conducted among health care professionals prescribing lithium. Target lithium serum levels and frequency of monitoring was assessed together with monitoring of physical and laboratory parameters. Reasons to and not to monitor and use of guidelines and institutional protocols, and local monitoring systems were investigated.

Results

The survey was completed by 117 health care professionals incorporating responses from twenty-four countries. All prescribers reported to monitor lithium serum levels on a regular basis, with varying target ranges. Almost all (> 97%) monitored thyroid and renal function before start and during maintenance treatment. Reported monitoring of other laboratory and physical parameters was variable. The majority of respondents (74%) used guidelines or institutional protocols for monitoring. In general, the prescriber was responsible for monitoring, had to request every monitoring parameter separately and only a minority of patients was automatically invited.

Conclusions

Lithium serum levels, renal and thyroid function were monitored by (almost) all physicians. However, there was considerable variation in other monitoring parameters. Our results help to understand why prescribers of lithium monitor patients and what their main reasons are not to monitor patients using lithium.

Electronic supplementary material

The online version of this article (10.1186/s40345-018-0120-1) contains supplementary material, which is available to authorized users.

Is environmental temperature related to renal symptoms, serum lithium levels, and other laboratory test results in current lithium users?

OBJECTIVE

Lithium continues to be an important mood disorder treatment. Although patients exposed to higher environmental temperatures may have serum lithium level elevations due to dehydration, there is conflicting data in the literature. In addition, no study has assessed the association between temperature and other renal laboratory tests and symptoms in lithium users.

METHODS

This is a cross-sectional analysis of 63 current lithium users who participated in the McGill Geriatric Lithium-induced Diabetes Insipidus Clinical Study. The relationship between mean daily temperature with diabetes insipidus symptoms, glomerular filtration rate, urine osmolality, serum sodium, lithium level, and lithium dose-level ratio was assessed.

RESULTS

Although a higher temperature on the day of laboratory testing trended toward being independently associated with a lower lithium dose-level ratio (Beta = -0.17, p = 0.08), this was not found when using a dichotomous measure of temperature (T > 20°C). No association was observed between temperature and other renal parameters.

CONCLUSIONS

The association of temperature with lithium levels, renal symptoms, and laboratory tests appears to be of relatively little clinical importance in lithium users in temperate climates. However, future research should re-examine patients living in climates with extreme temperatures (e.g., >40°C), who may theoretically be at higher risk.

The effects of lithium on renal function in older adults--a systematic review

Chronic renal failure (CRF) and nephrogenic diabetes insipidus (NDI) are potential consequences of chronic lithium use, while acute renal failure (ARF) has been described in lithium intoxication. We performed a systematic review of all studies pertaining to the effects of lithium on the kidney in older adults. The ARF incidence was 1.5% per person-year and concurrent loop diuretic and angiotensin-converting enzyme inhibitor use with lithium increased the risk. The CRF prevalence estimates varied from 1.2% to 34%, with risk factors including age, previous lithium intoxication, polyuria, previously impaired renal function, and decreased maximal urine osmolality. The prevalence of NDI varied widely from 1.8%  to 85%. Risk factors included lithium duration, dose, level, slow-release formulation, and clinical nonresponse. Except for amiloride use in NDI, there is little evidence for treatment of other lithium-induced adverse renal effects. Currently, there is no compelling evidence to suggest that lithium should be avoided in elderly patients for fear of renal side effects.