The challenge of managing drug interactions in elderly people

Drug therapy is essential when caring for elderly patients, but clearly it is a double-edged sword. Elderly patients are at high risk of having drug interactions, but the prevalence of these interactions is not well documented. Several types of interactions exist: drug-drug, drug-disease, drug-food, drug-alcohol, drug-herbal products, and drug-nutritional status. Factors such as age-related changes in pharmacokinetics and pharmacodynamics, frailty, interindividual variability, reduced homoeostatic mechanisms, and psychosocial issues need to be considered when drug interactions are assessed. Software can help clinicians to detect drug interactions, but many programmes have not been updated with the evolving knowledge of these interactions, and do not take into consideration important factors needed to optimise drug treatment in elderly patients. Any generated recommendations have to be tempered by a holistic, geriatric, multiprofessional approach that is team-based. This second paper in a series of two on prescribing in elderly people proposes an approach to categorise drug interactions, along with strategies to assist in their detection, management, and prevention.

Prise en charge thérapeutique des tics dans la maladie de Gilles de Tourette

Tourette's syndrome is a neuropsychiatric disorder characterised by both involuntary movements, tics, and psychiatric symptoms, attentional deficit disorder, hyperactivity, obsessive compulsive symptoms..., and can be the cause of major disability. Over the past 30 years, several types of treatment have been proposed for the treatment of tics in Tourette's Syndrome, ranging from psychotherapeutic approaches to neurosurgery. The education of the patient and his entourage is fundamental and must be offered to all patients. Psychotherapy does not directly improve the tics but contributes to a better adjustment of both patient and carers to his disability. The decision to start a course of drug therapy depends largely on the impact of the patient's tics on his personal life. Drug treatment relies on neuromodulators acting on a variety of neural systems and whose efficacy has been rarely demonstrated. The literature shows that the latest generation of dopaminergic antagonists have the highest benefit/risk ratio. Recently, deep brain stimulation, by modulating neuronal activity in structures involved in the pathophysiology of the disease, has become a promising therapeutical approach, producing a marked decrease in the severity of tics over that obtained with other treatments.

Neurosurgery at an earlier stage of Parkinson disease: A randomized, controlled trial

BACKGROUND

Stimulation of the subthalamic nucleus is an effective treatment for advanced Parkinson disease (PD) and is currently performed after a mean disease duration of 14 years, when severe motor complications have resulted in marked loss of quality of life. We examined whether surgery at an early stage would maintain quality of life as well as improve motor function.

METHODS

Twenty patients with PD of short duration (time elapsed since first symptom +/- SD: 6.8 +/- 1.0 years) with mild to moderate motor signs (Unified Parkinson's Disease Rating Scale III "off" medication: 29 +/- 12) who responded well to levodopa treatment were included in pairs, matched for age, duration and severity of disease, and impairment in socioprofessional functioning. Patients were prospectively randomized to undergo bilateral subthalamic nucleus stimulation (n = 10) or receive optimized medical treatment (n = 10). Parkinsonian motor scores, quality of life, cognition, and psychiatric morbidity were assessed at inclusion and at 6, 12, and 18 months after randomization.

RESULTS

Quality of life was improved by 24% in surgical and 0% in nonsurgical patients (p < 0.05). After 18 months, the severity of parkinsonian motor signs "off" medication, levodopa-induced motor complications, and daily levodopa dose were reduced by 69%, 83%, and 57% in operated patients and increased by 29%, 15%, and 12% in the group with medical treatment only (p < 0.001). Adverse events were mild or transient, and overall psychiatric morbidity and anxiety improved in the surgical group.

CONCLUSIONS

Subthalamic nucleus stimulation should be considered a therapeutic option early in the course of Parkinson disease.

To Treat or Not To Treat, That Is the Question: Proceedings of the Quebec Symposium for the Treatment of Osteoporosis in Long-Term Care Institutions, Saint-Hyacinthe, Quebec, November 5, 2004

OBJECTIVES

Patients in long-term care institutions (LTCI) are especially at risk for osteoporotic fractures owing to their lack of mobility, poor nutrition, and limited sun exposure. Previous reports have shown that osteoporosis is underdiagnosed and undertreated in LTCI despite the high incidence of osteoporotic fractures in these settings. This document has been developed to assist clinicians practicing in LTCI with the diagnosis and treatment of osteoporosis in their institutionalized patients. These proceedings offer an overview of the particular characteristics of patients at LTCI. Management strategies include both nonpharmacological and pharmacological interventions for the prevention and treatment of osteoporotic fractures in very frail older subjects.

PARTICIPANTS

This guide is an edited review of presentations and discussions held by specialists in osteoporosis in the elderly together with physicians and pharmacists practicing in LTCI in the province of Quebec. This symposium was held in Saint-Hyacinthe, Quebec on November 5, 2004.

VALUES

The value of a given diagnostic test or treatment option was determined based on the clinical experiences and opinions of the participants and a review of the literature from an evidence-based perspective.

RECOMMENDATIONS

All patients located at LTCI are at potential risk for osteoporotic fractures. Global interventions should include vitamin D, calcium, and a comprehensive exercise program. In patients who are at high risk for osteoporotic fractures or with previous fractures, pharmacological treatment should be started.

VALIDATION

These recommendations were approved during the final plenary of the symposium. All the prevailing opinions were summarized and included in this article.

Neurosurgery in Parkinson disease: A distressed mind in a repaired body?

OBJECTIVE

To prospectively evaluate the impact of subthalamic nucleus (STN) stimulation on social adjustment in patients with Parkinson disease (PD).

METHODS

Before and 18 to 24 months after bilateral STN stimulation, the authors assessed 29 patients with PD for motor disability, cognition (Mattis dementia rating scale, frontal score), psychiatric morbidity (Mini-5.0.0, MADRS, BAS), quality of life (PDQ-39), social adjustment (Social Adjustment Scale), and psychological status using unstructured in-depth interviews.

RESULTS

Despite marked improvement in parkinsonian motor disability, the absence of significant changes in cognitive status, and improvement of activities of daily living and quality of life by the end of the study, social adjustment did not improve. Several kinds of problems with social adjustment were observed, affecting the patients' perception of themselves and their body, marital situation, and professional life. Marital conflicts occurred in 17/24 couples. Only 9 out of 16 patients who had a professional activity before the operation went back to work after surgery.

CONCLUSION

After STN stimulation, patients experienced difficulties in their relations with themselves, their spouses, their families, and their socio-professional environment. The authors suggest a multidisciplinary psychosocial preparation and follow-up to help patients and their entourage cope with the sudden changes in their existence following successful neurosurgery.

Neurosurgery in Parkinson's disease: the doctor is happy, the patient less so?

Despite the overall excellent outcome of neurosurgery in patients with Parkinson's disease, there is often a contrast between the improvement in motor disability and the difficulties of patients to reintegrate a normal life. In this study, the personal, familial and professional difficulties experienced by patients two years after bilateral high frequency stimulation of the subthalamic nucleus were carefully analyzed. To avoid such socio-familial maladjustment, we strongly suggest taking into consideration the patients' psychological and social context before the operation and during the post-operative follow-up.

Stimulation of the subthalamic nucleus in Parkinson's disease: a 5 year follow up

BACKGROUND

The short term benefits of bilateral stimulation of the subthalamic nucleus (STN) in patients with advanced levodopa responsive Parkinson's disease (PD) are well documented, but long term benefits are still uncertain.

OBJECTIVES

This study provides a 5 year follow up of PD patients treated with stimulation of the STN.

METHODS

Thirty seven consecutive patients with PD treated with bilateral STN stimulation were assessed prospectively 6, 24, and 60 months after neurosurgery. Parkinsonian motor disability was evaluated with and without levodopa treatment, with and without bilateral STN stimulation. Neuropsychological and mood assessments included the Mattis Dementia Rating Scale, the frontal score, and the Montgomery-Asberg Depression Rating Scale (MADRS).

RESULTS

No severe peri- or immediate postoperative side effects were observed. Six patients died and one was lost to follow up. Five years after neurosurgery: (i) activity of daily living (Unified Parkinson Disease Rating Scale (UPDRS) II) was improved by stimulation of the STN by 40% ("off" drug) and 60% ("on" drug); (ii) parkinsonian motor disability (UPDRS III) was improved by 54% ("off" drug) and 73% ("on" drug); (iii) the severity of levodopa related motor complications was decreased by 67% and the levodopa daily doses were reduced by 58%. The MADRS was unchanged, but cognitive performance declined significantly. Persisting adverse effects included eyelid opening apraxia, weight gain, addiction to levodopa treatment, hypomania and disinhibition, depression, dysarthria, dyskinesias, and apathy.

CONCLUSIONS

Despite moderate motor and cognitive decline, probably due to disease progression, the marked improvement in motor function observed postoperatively was sustained 5 years after neurosurgery.

The Temperament and Character Inventory-Revised (TCI-R): psychometric characteristics of the French version

OBJECTIVE

To explore the psychometric characteristics of a modified version of the Cloninger's personality questionnaire, the Temperament and Character Inventory-Revised (TCI-R).

METHOD

A 482-subject sample, including clinical and non-clinical subjects, completed the TCI-R. We performed principal component analyses and explored the factorial structure of the questionnaire, and the internal consistency of each dimension.

RESULTS

The factorial structure of the TCI-R was well defined as expected and similar to those shown with the TCI. Robust factors were obtained for Reward Dependence and Persistence in the TCI-R, even more clearly than in the original TCI. All dimensions obtained higher alpha Cronbach coefficients with the TCI-R than with the TCI. We obtained highly satisfying reliability coefficients in test-retest and TCI/TCI-R comparisons.

CONCLUSION

The TCI-R seems to have similar psychometric and feasibility characteristics as those of the initial version, but with significant improvements in terms of factorial structure and internal consistency of most dimensions.

Tourette's syndrome and deep brain stimulation

In this prospective double blind randomised "N of 1" study, a patient with a severe form of Tourette's syndrome was treated with bilateral high frequency stimulation of the centromedian-parafascicular complex (Ce-Pf) of the thalamus, the internal part of the globus pallidus (GPi), or both. Stimulation of either target improved tic severity by 70%, markedly ameliorated coprolalia, and eliminated self injuries. Severe forms of Tourette's syndrome may benefit from stimulation of neuronal circuits within the basal ganglia, thus confirming the role of the dysfunction of limbic striato-pallido-thalamo-cortical systems in this disorder.

Coadministration of Gatifloxacin and Multivitamin Preparation Containing Minerals: Potential Treatment Failure in an Elderly Patient

OBJECTIVE:

To report a case of probable treatment failure in a patient receiving gatifloxacin and a multivitamin preparation containing minerals.

CASE SUMMARY:

A 77-year-old white woman was prescribed gatifloxacin for hospital-acquired bacterial pneumonia. She was also receiving calcium carbonate 500 mg twice daily and a multivitamin preparation containing minerals once a day. Three days after gatifloxacin was started, the patient was still febrile, coughing, and not responding clinically. It was noted that nurses were administering the gatifloxacin tablet at the same time as the multivitamin tablet. The time of administration for gatifloxacin was changed to 6 hours after the patient received her multivitamin preparation. Two days later, she clinically improved.

DISCUSSION:

Studies have shown that the bioavailability of gatifloxacin is decreased with concurrent administration of antacids containing aluminum or magnesium; dietary supplements containing zinc, magnesium, and iron; multivitamin preparations containing minerals; and sucralfate. An objective causality assessment revealed that the adverse drug effect was probable.

CONCLUSIONS:

This case illustrates the need to recognize this potential interaction and to know how to avoid possible treatment failure.

Valproic Acid—Induced Hyperammonemia and Thrombocytopenia in an Elderly Woman

OBJECTIVE

To describe a case of oral valproic acid—induced hyperammonemia and thrombocytopenia in an elderly patient.

CASE SUMMARY

A 76-year-old white woman presented to the emergency department with generalized weakness, confusion, nausea, and vomiting. She was taking sodium divalproex 750 mg 3 times daily, with valproic acid concentration 144 mg/L. She was admitted to the medical ward. The dose of sodium divalproex was decreased and discontinued. During her hospital stay, the woman's ammonia level rose to 211 μg/dL despite a normal valproic acid concentration. She was confused, somnolent, and had decreased mobility. Her platelet count decreased from 133 to 86 × 103/mm 3 . Gabapentin was prescribed for seizure control. The patient's mental status, ammonia level, and platelet count returned to baseline following discontinuation of valproic acid.

DISCUSSION

It has been reported that valproic acid can interfere with the enzyme carbamoylphosphate synthetase, which is responsible for incorporating ammonia into the urea cycle. It has also been reported that valproic acid can increase the transport of glutamine across the mitochondrial membrane in the kidney, thereby increasing the production of ammonia. The etiology of valproic acid—induced thrombocytopenia has not been elucidated. Using the Naranjo probability scale, a probable relationship between hyperammonemia and valproic acid and a possible relationship between thrombocytopenia and valproic acid were determined.

CONCLUSIONS

Valproic acid can be associated with hyperammonemia and thrombocytopenia. Clinicians should be aware of changes in patients' cognitive and functional capacity, especially elderly patients on sodium divalproex.

Behavioural disorders, Parkinson's disease and subthalamic stimulation

OBJECTIVE

to analyse 24 parkinsonian patients successfully treated by bilateral STN stimulation for the presence of behavioural disorders.

METHOD

patients were evaluated retrospectively for adjustment disorders (social adjustment scale, SAS), psychiatric disorders (comparison of the results of psychiatric interview and the mini international neuropsychiatric inventory) and personality changes (IOWA scale of personality changes).

RESULTS

parkinsonian motor disability was improved by 69.5% and the levodopa equivalent daily dosage was reduced by 60.5%. Social adjustment (SAS) was considered good or excellent in nine patients, moderately (n=14), or severely (n=1) impaired in 15 patients. Psychiatric disorders consisted of amplification or decompensation of previously existing disorders that had sometimes passed unnoticed, such as depressive episodes (n=4), generalised anxiety (n=18), and behavioural disorders with drug dependence (n=2). Appearance of mild to moderate emotional hyperreactivity was reported in 15 patients. Personality traits (IOWA scale) were improved in eight patients, unchanged in seven, and aggravated in eight

CONCLUSION

Improvement in parkinsonian motor disability induced by STN stimulation is not necessarily accompanied by improvement in psychic function and quality of life. Attention is drawn to the possible appearance of personality disorders and decompensation of previous psychiatric disorders in parkinsonian patients who are suitable candidates for neurosurgery. We suggest that a careful psychological and psychiatric interview be performed before surgery, and emphasise the need for psychological follow up to ensure the best possible outcome.