Antidepressant Use in Geriatric Populations: The Burden of Side Effects and Interactions and Their Impact on Adherence and Costs

Thomson Reuters, Healthcare & Science, WA, DC, USA.
The American journal of geriatric psychiatry: official journal of the American Association for Geriatric Psychiatry (Impact Factor: 4.24). 03/2011; 19(3):211-21. DOI: 10.1097/JGP.0b013e3181f1803d
Source: PubMed


The study aimed to determine the prevalence of documented side effects and drug–drug interactions in older adults using antidepressants and their implications for adherence.
Data were from the MarketScan Medicare Database,which comprises insurance claims from retirees with employer-sponsored Medicare supplemental insurance. Subjects were aged 65 years or older, new antidepressant users, and had a depression diagnosis between July 1, 2001, and December 31, 2006.Twelve commonly reported antidepressant side effects were identified in the month after drug initiation through International Classification of Diseases, Ninth Revision,Clinical Modification diagnoses. Potential drug- drug interactions involving an antidepressant and another drug were identified during the 1 year after antidepressant initiation using MicroMedex DRUG-REAX software. Multinomial logistic regression was used to determine the association of side effects and potential interactions with refills rates, switching, and discontinuation.
The presence of a side effect was associated with a 4.7 percentage point increase in the probability of switching (from 16.5% to 21.7%) and a 3.7 percentage point increase in the discontinuation rate (from 22% to 25.7%). Among the 39,512 treatment-naive antidepressants users, 25.4% hadpotential contraindicated or major interactions, 36.1% had moderate interactions,and 38.5% had minor or no interactions. The presence of potential contraindicated or potential major interactions increased the probability of switching by 19.5 percentage points and had a minimal effect on discontinuation.
Although antidepressant medications have been demonstrated to be effective in treatment of geriatric depression, this study highlights the complexity of antidepressant prescribing in this population and the need for clinicians to be aware of potential drug- drug interactions and side effects.

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  • The American journal of geriatric psychiatry: official journal of the American Association for Geriatric Psychiatry 03/2011; 19(3):197-200. DOI:10.1097/JGP.0b013e318209c594 · 4.24 Impact Factor
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    ABSTRACT: : To 1) compare the accuracy of the Montgomery-Åsberg Depression Rating Scale (MADRS) and the Cornell Scale for Depression in Dementia (CSDD) in nursing home residents with dementia when professional caregivers are the only available source of information and 2) explore different methods to account for missing items. : Cross-sectional design. : Nursing home (NH). : One hundred one residents with dementia. : NH residents with dementia were assessed on the presence of clinical depression using Provisional Diagnostic Criteria for Depression of Alzheimer's Disease. The MADRS and CSDD were administered in a structured interview with professional primary caregivers. : Receiver operating characteristic analyses revealed no significant differences between areas under the empirical curve for MADRS and CSDD. Imputation of a lowest possible item score for missing items revealed larger areas than three other methods (significant result only for CSDD). A MADRS cutoff score of ">13" yielded the highest sum of sensitivity (78%) and specificity (66%). A CSDD cutoff score of ">6" yielded the highest sum of sensitivity (94%) and specificity (49%). Both scales showed high negative predictive values up to 100% and low positive predictive values not exceeding 50%. : The proxy-based MADRS and CSDD did not differ in distinguishing depressed from nondepressed NH residents and may be used for screening purposes. For missing items, imputation of a lowest possib le item score may be applied. The MADRS and CSDD may be better used for ruling out rather than for ruling in depression.
    The American journal of geriatric psychiatry: official journal of the American Association for Geriatric Psychiatry 10/2011; 20(11):985-93. DOI:10.1097/JGP.0b013e318233152b · 4.24 Impact Factor
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    ABSTRACT: After the introduction of selective serotonin reuptake inhibitors (SSRIs), other newer antidepressants with different mechanisms of action have been introduced in clinical practice. Because antidepressants are commonly prescribed in combination with other medications used to treat co-morbid psychiatric or somatic disorders, they are likely to be involved in clinically significant drug interactions. This review examines the drug interaction profiles of the following newer antidepressants: escitalopram, venlafaxine, desvenlafaxine, duloxetine, milnacipran, mirtazapine, reboxetine, bupropion, agomelatine and vilazodone. In general, by virtue of a more selective mechanism of action and receptor profile, newer antidepressants carry a relatively low risk for pharmacodynamic drug interactions, at least as compared with first-generation antidepressants, i.e. monoamine oxidase inhibitors (MAOIs) and tricyclic antidepressants (TCAs). On the other hand, they are susceptible to pharmacokinetic drug interactions. All new antidepressants are extensively metabolized in the liver by cytochrome P450 (CYP) isoenzymes, and therefore may be the target of metabolically based drug interactions. Concomitant administration of inhibitors or inducers of the CYP isoenzymes involved in the biotransformation of specific antidepressants may cause changes in their plasma concentrations. However, due to their relatively wide margin of safety, the consequences of such kinetic modifications are usually not clinically relevant. Conversely, some newer antidepressants may cause pharmacokinetic interactions through their ability to inhibit specific CYPs. With regard to this, duloxetine and bupropion are moderate inhibitors of CYP2D6. Therefore, potentially harmful drug interactions may occur when they are coadministered with substrates of these isoforms, especially compounds with a narrow therapeutic index. The other new antidepressants are only weak inhibitors or are not inhibitors of CYP isoforms at usual therapeutic concentrations and are not expected to affect the disposition of concomitantly administered medications. Although drug interactions with newer antidepressants are potentially, but rarely, clinically significant, the use of antidepressants with a more favourable drug interaction profile is advisable. Knowledge of the interaction potential of individual antidepressants is essential for safe prescribing and may help clinicians to predict and eventually avoid certain drug combinations.
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