Pharmacokinetic aspects of antidepressant treatment in the elderly

A double-blind, randomized, 26-week study comparing the cognitive and psychomotor effects and efficacy of 75 mg (37.5 mg b.i.d.) venlafaxine and 75 mg (25 mg mane, 50 mg nocte) dothiepin in elderly patients with moderate major depression being treated in general practice

To investigate the efficacy and cognitive and psychomotor effects of venlafaxine and dothiepin in elderly patients with moderate major depression. A prospective, randomized, double-blind, parallel-group, active comparator controlled study was conducted. Eighty-eight patients (aged > or = 60 years) were enrolled. Each patient received either venlafaxine (immediate release formulation) 37.5 mg twice per day or dothiepin 25 mg mane followed by 50 mg nocte for 26 weeks. Efficacy was assessed with the Montgomery-Asberg Depression Rating Scale and the Hamilton Depression Rating Scale. A psychometric test battery to assess cognitive function, activities of daily living and sleep consisted of Critical Flicker Fusion (CFF), Short-term Memory--Kim's Game, Cognitive Failures Questionnaire, Milford Epworth Sleepiness Scale, Leeds Sleep Evaluation Questionnaire, and an Accident Scoring Questionnaire. Quality of Life Questionnaires (Short Form 36 and Quality of Life in Depression Scale) were also administered. Venlafaxine significantly (p < 0.05) raised CFF scores compared to baseline but had no effect on any other measure. Dothiepin significantly (p < 0.05) lowered CFF threshold, and increased ratings of both sedation and difficulty in waking. The results showed that venlafaxine at doses of 37.5 mg b.i.d. in elderly depressed patients is free from disruptive effects on cognitive function and psychomotor performance.

Serotonin receptor subtype gene expression in the hippocampus of aged rats following chronic amitriptyline treatment

The raphe-hippocampal 5-HT system plays a key role in the modulation of mood, memory and neuroendocrine responses. In the elderly, there is an increased incidence of disturbances of these functions. We examined the effects of ageing and of chronic antidepressant treatment upon 5-HT receptor subtype mRNA expression in the hippocampus and raphe of cognitively tested rats. Amitriptyline treatment decreased 5-HT1A receptor mRNA expression in the dorsal raphe nucleus of the aged rats (24% fall compared to saline treated controls, p<0.01) but not in the young rats. Neither age nor amitriptyline (10 mg/kg, i.p.) administration for 10 weeks altered 5-HT1A, 5-HT2A, 5-HT2C or 5-HT7 receptor mRNA expression in any hippocampal subregion. This suggests a difference in responsiveness to amitriptyline with ageing originating at the level of the raphe 5-HT1A autoreceptor gene expression.

Management of treatment resistance in the depressed geriatric patient

The treatment of depression in geriatric patients is challenging on all levels. Recognition, compliance, medical comorbidity, tolerance of drug regimens, and accessibility of the patient to therapy all represent major clinical problems. Treating depression in elderly, disabled patients requires patience, keen observation skills, and much flexibility. It is critical that these patients trust their physicians and have ready access if problematic side effects develop. In general, when treating patients with a history of failure to respond, the clinician should choose a medication with a tolerable side-effect profile, and persist with it as long as steady, slow gains are being made. Dosages should be maximized to clinical tolerance prior to considering switching agents or augmentation strategies. It is probably wiser to augment than switch if a partial response has been obtained. Particularly among the medically ill elderly, any "lost ground" may be very difficult to replace. All available psychosocial resources should be assessed and brought to bear productively in the treatment context. We are quite far from a full clinical understanding of "treatment resistance" in elderly depressive patients, but the eminent treatability of depression in elderly patients encourages creative exploration of treatment regimens. Rigorous, placebo-controlled studies of representative samples of elderly patients are needed to clarify the diverse interactions among the many pharmacologic agents available to treat resistant/refractory depression in the elderly.