[Lithium: 55 years of history in the therapy of bipolar affective disorder]

Quality, origins and limitations of common therapeutic drug reference intervals

Therapeutic drug monitoring (TDM) is used to manage drugs with a narrow window between effective and toxic concentrations. TDM involves measuring blood concentrations of drugs to ensure effective therapy, avoid toxicity and monitor compliance. Common drugs for which TDM is used include aminoglycosides for infections, anticonvulsants to treat seizures, immunosuppressants for transplant patients and cardiac glycosides to regulate cardiac output and heart rate. An essential element of TDM is the provision of accurate and clinically relevant reference intervals. Unlike most laboratory reference intervals, which are derived from a healthy population, TDM reference intervals need to relate to clinical outcomes in the form of efficacy and toxicity. This makes TDM inherently more difficult to develop as healthy individuals are not on therapy, so there is no "normal value". In addition, many of the aforementioned drugs are old and much of the information regarding reference intervals is based on small trials using methods that have changed. Furthermore, individuals have different pharmacokinetics and drug responses, particularly in the context of combined therapies, which exacerbates the challenge of universal TDM targets. This focused review examines the origins and limitations of existing TDM reference intervals for common drugs, providing targets where possible based on available guidelines.

Evaluation of parathyroid function and mineral metabolism in psychiatric patients using lithium salts

OBJECTIVE

To evaluate parathyroid function and mineral metabolism in psychiatric patients users of lithium salts.

MATERIALS AND METHODS

We measured the serum levels of calcium, ionized calcium, inorganic phosphorus, alkaline phosphatase, albumin, parathyroid hormone (PTH), urea, creatinine, 25-hydroxy-vitamin D and lithium of 35 patients diagnosed with bipolar disorder in use of lithium carbonate (LC) for at least one year (Lithium Group - LG) and 35 healthy subjects (Control Group - CG).

RESULTS

The LG and CG were matched by sex and age. There was only statistic difference in relation to the levels of PTH and ionized calcium, with p < 0.004 and p < 0.03, respectively. Secondary form of hyperparathyroidism (HPT) was found in eight (22.8%) LG patients and in none of the CG. There was no correlation between lithemia, usage time and dosage of LC.

CONCLUSION

Our data demonstrate that lithium may create an imbalance in the parathyroid axis, characterized by elevated levels of PTH.

[Nursing care of a patient with bipolar disorder and lithium-induced nephrogenic diabetes insipidus]

Bipolar disorder is one of the most common, severe and persistent mental disorders. The evaluation of all data and variables related to bipolar disorder is a difficult task, because there is no clear agreement on what should be included in this category. One of the traditional treatments for this disease is the lithium metal that is administered in the form of lithium salt. Lithium has a narrow therapeutic window and there is a significant risk of complications arising from its use, mainly neurological and renal. In the case presented, the preparation of a care plan is described for a patient diagnosed with bipolar disorder who suffered a complication with lithium treatment. To do this, it was decided to use a standardized care plan and later completed it with diagnostic, objectives and interventions to the specific needs of the patient, aimed at achieving optimal levels of independence.