Older people admitted to hospital are at high risk of rehospitalization and medication errors. We have demonstrated, in a randomized controlled trial, that a clinical pharmacist intervention reduces the incidence of revisits to hospital for patients aged 80 years or older admitted to an acute internal medicine ward. The aims of this thesis were to further study the effects of the intervention and to investigate possibilities of targeting the intervention by identifying predictors of treatment response or adverse health outcomes. The effect of the pharmacist intervention on the appropriateness of prescribing was assessed, by using three validated tools. This study showed that the quality of prescribing was improved for the patients in the intervention group but not for those in the control group. However, no association between the appropriateness of prescribing at discharge and revisits to hospital was observed. Subgroup analyses explored whether the clinical pharmacist intervention was equally effective in preventing emergency department visits in patients with few or many prescribed drugs and in those with different levels of inappropriate prescribing on admission. The intervention appeared to be most effective in patients taking fewer drugs, but the treatment effect was not altered by appropriateness of prescribing. The most relevant risk factors for rehospitalization and mortality were identified for the same study population, and a score for risk-estimation was constructed and internally validated (the 80+ score). Seven variables were selected. Impaired renal function, pulmonary disease, malignant disease, living in a nursing home, being prescribed an opioid and being prescribed a drug for peptic ulcer or gastroesophageal reflux disease were associated with an increased risk, while being prescribed an antidepressant drug (tricyclic antidepressants not included) was linked with a lower risk. These variables made up the components of the 80+ score. Pending external validation, this score has potential to aid identification of high-risk patients. The last study investigated the occurrence of prescription errors when patients with multi-dose dispensed (MDD) drugs were discharged from hospital. Twenty-five percent of the MDD orders contained at least one medication prescription error. Almost half of the errors were of moderate or major severity, with potential to cause increased health-care utilization.

Herbal medicines (HMs) have been used to supplement, maintain, and treat health conditions, and have inspired the development of many Western pharmaceuticals. Migrant South Asian (SA) communities in the UK have brought with them their own traditional forms of medicine, yet little is known about their current use of HMs in the UK. Consuming HMs alongside conventional Western medicines could affect pharmacological treatment and lead to herb-drug interactions; hence, healthcare professionals (HCPs) should be aware of their patients’ use of HMs. The import of HMs to the UK raises concerns over the quality, safety and regulation of HMs. Deoxyribonucleic acid (DNA) barcoding can be used to discriminate between different species, and identify contaminants and adulterants, thus can be used for the authentication of HMs. The South Asian Traditional Medicines (SATMED) questionnaire explored the knowledge and use of HMs by diasporic SA communities in the UK. It uncovered a vast range of HMs which were used by participants, where ingredients were sourced from, the concurrent use of herbal and Western medicines, and how minor ailments were treated. An online survey designed to investigate UK based practitioners’ views of HMs revealed that HCPs claimed to lack sufficient knowledge of HMs. HCPs said they needed more training on HMs to help them make better informed decisions. Tulsi (Ocimum tenuiflorum L.) was identified as a culturally and commercially valuable plant, which was used for molecular analysis. A variety of tulsi samples were collected for authentication: community samples from SA families in the UK, commercial samples, and referenced specimens. Both ITS and trnH-psbA regions were successfully used to distinguish between several Ocimum species, and identify a potential species substitution. This research represents the first time that DNA based methods have been used to authenticate medicinal plants species used by migrant SA communities living in the UK. The results of this multi-disciplinary study provide a unique contribution to the evolving discipline of ethnopharmacology.

Contexte : La polypharmacie et le taux de mortalité des patients atteints d’insuffisance cardiaque (IC) croissent avec l’âge. Cependant, le lien entre la polypharmacie et la mortalité des malades d’IC est peu documenté au Canada. Il paraît donc nécessaire d’étudier l’association entre la polypharmacie aux médicaments cardiovasculaires et non cardiovasculaires et le risque de mortalité chez les patients âgés (≥ 66 ans), dont un diagnostic récent d’IC a été posé. Méthodes : À partir de deux bases de données administratives du Québec, une cohorte de patients âgés avec un diagnostic récent d’IC entre 1998 et 2015 a été constituée. Un devis cas-témoin imbriqué dans cette cohorte a permis d’apparier les cas de décès aux contrôles sur l’âge, le sexe et leur durée de suivi. La polypharmacie a été évaluée dans les trois derniers mois précédant la date de décès des patients. La relation entre le risque de mortalité et la polypharmacie aux médicaments cardiovasculaires (≥5 médicaments) et non cardiovasculaires (≥ 6 médicaments) a été testée par application d’une régression logistique conditionnelle ajustée aux comorbidités et aux médicaments cardiovasculaires. Résultats : L’échantillon comportait 1530 cas d’âge moyen de 83,4 ans. Parmi eux, 98,6 % présentaient au moins une comorbidité. Leur prévalence d’exposition à la polypharmacie aux médicaments cardiovasculaires était de 65,0 % et celle aux médicaments non cardiovasculaires de 63,9 %. Les données montraient une réduction importante du nombre de médicaments dans le dernier mois précédant la date de décès. Les analyses, ajustées aux comorbidités et aux médicaments cardiovasculaires, ont révélé que les patients exposés à la polypharmacie ≥ 6 médicaments non cardiovasculaires avaient 1,43 fois le risque de mortalité (IC 95 % : 1,28-1,60), comparés aux patients avec une polypharmacie < 6 médicaments non cardiovasculaires. En revanche, cette association était non significative pour les aînés avec une polypharmacie ≥ 5 médicaments cardiovasculaires (OR=0,91; IC 95 % : 0,79-1,04). Conclusion : Cette étude a révélé une association positive entre la polypharmacie aux médicaments non cardiovasculaires et le risque mortalité chez les patients âgés nouvellement diagnostiqués d’une IC. / Background : Polypharmacy and the mortality rate of heart failure (HF) patients increase with age. However, the link between polypharmacy and HF patients mortality is poorly documented in Canada. Therefore, it’s necessary to study the association between polypharmacy with cardiovascular and non-cardiovascular drugs and the risk of mortality in elderly (≥ 66 years) newly diagnosed HF patients. Methods : Using two Quebec administrative databases, a cohort of elderly patients with a recent diagnosis of HF between 1998 and 2015 was established. A nested case-control design study allowed the cases of death to be matched to controls on age, sex and duration of the follow-up. Polypharmacy was assessed in the last three months prior to the date of patient death. The relationship between mortality risk and polypharmacy to cardiovascular (≥ 5 drugs) and non-cardiovascular (≥ 6 drugs) drugs was tested using conditional logistic regression adjusted for comorbidities and cardiovascular drugs. Results : The sample consisted of 1530 cases with a mean age of 83.4 years. Among them, 98.6% had at least one comorbidity. Their prevalence of polypharmacy to cardiovascular drugs was 65.0% and 63.9% to non-cardiovascular drugs. The data showed a significant reduction in medications was seen in the last month the date of death. Comorbidities and cardiovascular drugs adjusted analyses reported that patients with polypharmacy ≥ 6 non-cardiovascular drugs had 1.43 times the risk of mortality (95 % CI : 1.28-1.60) compared to patients with polypharmacy < 6 non-cardiovascular drugs. On the other hand, this association wasn’t statistically significant for elderly with polypharmacy ≥ 5 cardiovascular drugs (OR=0.91; 95 % CI : 0.79-1.04). Conclusion : This study found a positive association between polypharmacy with non-cardiovascular drugs and the risk of mortality in elderly patients newly diagnosed with HF.

Background: Medications are used to treat, cure, or relieve symptoms of diseases, but there is a risk with the use of medications. Drug-related-problems are known to increase morbidity and mortality. Incorrect medical list and discrepancies in these lists can lead to drug-related problems as side effects, hospitalization, non-compliance, drug interactions and overtreated or undertreated patients. Discrepancies can be for example: more prescriptions than necessary, outdated prescriptions, i.e., medicines that will not be used, prescriptions with incorrect dosing and missing prescriptions i.e., medicines used by patients that cannot be seen in the medication list. Purpose:  The aim of this study was to investigate discrepancies in the Swedish prescription list "My saved prescriptions at the pharmacy". The secondary aim was to investigate how common it is to use this prescription list or the dosage label on the medicine packaging to know which medicines to use and which dosage. Methods: The data collection was performed by four pharmacy students at seven pharmacies in Sweden over a period of three weeks during Jan-Feb. 2021 where the prescription list was investigated together with patients to identify any discrepancies. The study included patients who was over 18 years old, spoke Swedish, had three or more prescribed drugs, and agreed to participate.  Results A total of 215 patients were interviewed, where 61% had one or more discrepancies in their medication list. A total of 1717 prescriptions were analyzed, of which 10% were double prescriptions (n = 167), 8% outdated prescriptions (n = 141) and 3% prescriptions with the wrong dosage (n = 42). When analyzing the primary sources of information used by patients to know which medicine to use, the printout of the list "my saved prescriptions at the pharmacy” dominated (n = 72).  Most used information source to know drug dosage was the dosage label on the medicine packaging (n = 112). Conclusions: It is important to have an updated and correct information in the medication list, to prevent drug-related-problems caused by discrepancies. It becomes even more important when we see that the medication list "My saved prescriptions at the pharmacy" and dosage label (containing the same information in the medication list), are the most used primary sources by patients to know which drug to use and in what dosage. Finally, results show a relationship between the number of prescribed drugs and the number of discrepancies that occur, and therefore we see more discrepancies in elderly patients who are usually ill and are being treated for several diseases.  There are opportunities for further research to study e.g., which drug-related-problems are caused by discrepancies in the medication list as well as the degree of danger in these problems. / Användning av läkemedel som avses behandla, lindra eller bota sjukdomar kan i vissa fall utgöra en risk för patientens hälsa. Läkemedelsrelaterade problem p.g.a. felmedicinering står för en stor andel av morbiditeten och mortaliteten bland patienter. En bidragande orsak är ofullständig information i patientens läkemedelslista.   Syftet med studien var att undersöka antalet avvikelser som förekommer i receptlistan ”Mina sparade recept på apoteket”. Studiens sekundära syfte var att undersöka vilka informationskällor som användes av patienter för att veta vilka läkemedel som ska adminstreras och i vilken dos dosering.  Studiens metod var att intervjua patienter som kom till apoteket för att hämta ut läkemedel till sig själva och uppfyllde inklusionskriterierna för att delta i studien. Studien utfördes av fyra farmaceutstudenter på sju olika apotek i fyra olika städer i Sverige som tillsammans med patienter gick igenom receptlistan för att identifiera avvikelser.  Resultatet blev totalt 1717 recept som studerades varav 21% hade avvikelser. Av recepten var 10% dubbla recept (n = 167), 8% inaktuella recept (n = 141) och 3% recept med fel dosering (n = 42). Vid analys av primära informationskällor som används dominerade utskrift av listan ”Mina sparade recept på apoteket” (n = 72) resp. doseringsetiketten på läkemedelsförpackningen (n = 112).  Resultaten visade även ett samband mellan ökade antal läkemedel och antalet avvikelser.  Avvikelser i läkemedelslistan Mina sparade recept är vanligt förekommande därmed är listan inte alltid aktuell. Det är vanligt att denna lista och doseringsetikett på läkemedels-förpackningar används som primära källor av patienter under deras behandlingstid vilket kan innebära en risk för läkemedelsrelaterade problem. En gemensam nationell läkemedelslista är en möjlig lösning till att förebygga läkemedelsrelaterade problem orskade av infromationsbrist i läkemedelslistor. Det är dock nödvändigt med läkemedelsgenomgångar för att bibehålla uppdateringen av listan.

Antecedentes y Objetivo Los adultos mayores exhiben mayor probabilidad de presentar Interacciones droga-droga (DDI) potencialmente graves. El objetivo del estudio fue identificar la frecuencia de las interacciones farmacológicas potencialmente graves en adultos mayores atendida en un hospital de referencia peruano, así como sus factores asociados. Materiales y Métodos Estudio transversal analítico en pacientes atendidos en consultorio externo de geriatría en el Hospital Centro Médico Naval durante noviembre del 2018 - marzo 2019. Se registraron los datos consignados en las historias clínicas y se evaluó la presencia de DDIs utilizando la herramienta Lexicomp®️. Se evaluó la asociación con los potenciales factores utilizando un modelo de Regresión de Poisson con varianzas robustas. Resultados Se analizaron 306 historias clínicas. La mediana fue de edad de 74 (68-82) años con predominancia masculina (63,40%). El 27,78% de la población presentó interacciones farmacológicas potencialmente graves. El 61,76% recibía de 5 o más fármacos. El 97,06% presentó multimorbilidad y el 56,21% presentó hipertensión arterial. En el análisis bivariado, los factores significativamente asociados a las interacciones farmacológicas potencialmente graves fueron el género femenino (PR:0,65; IC:0,45-0,93; p=0,018), la osteoartritis (PR:1,82; IC:1,28-2,56; p=0,001), la presencia de síntomas depresivos (PR:1,80; IC:1,14-2,87; p=0,012) y la polifarmacia (PR:8,15; IC:3,66-18,11; p<0,001). En el análisis multivariado, los factores significativamente asociados a DDIs potencialmente graves fueron la polifarmacia (PR:8,05; IC:3,61-17,92; p<0,001) y la osteoartritis (PR:1,76; IC:1,29-2,40; p<0,001). Conclusiones La polifarmacia es el principal factor de riesgo para la presencia de DDIs graves. Se debe evaluar rutinariamente las posibles interacciones medicamentosas en pacientes geriátricos polimedicados. / Background and Objectives Elderly are more likely to have potentially serious Drug-Drug Interactions (DDIs). The objective of the study was to identify the frequency of potentially serious drug interactions in the population of elderly treated at a Peruvian referral hospital, as well as their associated factors. Materials and Methods Analytical cross-sectional study in a population attended in the outpatient clinic of geriatrics at the Hospital Naval Medical Center during November 2018 - March 2019. The data recorded in the medical records were recorded and the presence of DDIs was evaluated using the Lexicomp®️ tool. The association with the potential factors was evaluated using a Poisson regression model with robust variances. Results We analyzed 306 clinical histories. The average age of 74 (68-82) years with male predominance (63,40%). 27,78% of the population had potentially serious drug interactions. Likewise, 61,76% consumed 5 to more drugs. 97,06% presented multimorbidity and 56,21% had arterial hypertension. In the bivariate analysis, the factors significantly associated with the potentially serious pharmacological interactions were the female gender (PR:0,65; CI:0,45-0,93; p=0,018), the presence of osteoarthritis (PR:1,82; CI:1,28-2,56; P=0,001), depressive symptoms (PR:1,80; CI:1,14-2,87; p=0,012), and polypharmacy (PR:8,15; CI:3,66-18,11; p<0,001). In the multivariate analysis, the factors significantly associated with potentially serious DDI were polypharmacy (PR:8,05; CI:3,61-17,92; P<0,001) and osteoarthritis (PR:1,76; CI:1,29-2,40; p<0,001). Conclusions Polypharmacy is the main risk factor for the presence of serious DDIs. Possible drug interactions should be routinely evaluated in polymedicated geriatric patients. / Tesis

Det övergripande syftet med den här avhandlingen har varit att, inom området läkemedelsinformatik, studera utvecklingen av elektroniska stöd inom läkemedelsförskrivning; för klinisk praxis, uppföljning och forskning. Under århundraden har det handskrivna receptet varit det sätt, med vilket läkare förmedlat sina läkemedelsordinationer till apotekare, vilket också för patienten blivit en informationskälla för hur läkemedel ska användas för att göra bästa nytta. Nu genomgår receptet en förändring från pappersbaserat till elektroniskt meddelande och att anpassa en traditionell process till en ny elektronisk era innebär både möjligheter och utmaningar. Studierna som ingår i avhandlingen har visat att exponeringen av förskrivna läkemedel i en allmän befolkning har ökat under de senaste tre decennierna. Risken för potentiella interaktioner mellan läkemedel, varmed avses den risk som finns att olika läkemedel kan påverka varandras effekter och biverkningar, har också visat sig öka starkt desto fler läkemedel som används av en individ. Denna ökade samtidiga användning av flera olika läkemedel, så kallad polyfarmaci, medför att det finns en större anledning för förskrivare och farmacevter att uppmärksamma risken för potentiella interaktioner mellan läkemedel. De nyinrättade nationella receptregistren över uthämtad receptförskriven medicin bör användas bland annat för att upptäcka potentiella läkemedelsinteraktioner, såväl i vårdens utövning som inom läkemedelsepidemiologisk forskning. Den svenska läkemedelsförteckningen, som omfattar information om uthämtade receptförskrivna läkemedel för huvuddelen av den svenska befolkningen, bedöms ha en stor klinisk potential. Den enskilde individens historiska information om uthämtade läkemedel är tillgänglig för individen på Internet med hjälp av e-legitimation; även förskrivare och farmacevter på apotek kan ta del av informationen med den enskildes samtycke. Brist på tillgång till enhetliga och säkra autenticeringsmetoder inom hälso- och sjukvården kan dock fördröja tillgången på individuell läkemedelsinformation för förskrivare. I och med att de flesta recepten i Sverige nu skrivs och överförs elektroniskt är det viktigt att kvalitetsmässiga aspekter tas tillvara så att en iakttagen ökad risk för receptförskrivningsfel inte överförs i informationskedjan. Avhandlingens slutsats är att e-förskrivning, med kommunikation och användning av lagrad information om receptexpeditioner, möjliggör att läkemedelsbehandling som process kan följas och studeras på ett helt nytt / The thesis aimed to study the developments, in the area of pharmacoinformatics, of the electronic prescribing and dispensing processes of drugs - in medical praxis, follow-up, and research. For hundreds of years, the written prescription has been the method of choice for physicians to communicate decisions on drug therapy and for pharmacists to dispense medication. Successively the prescription has also become a source of information for the patient about how to use the medication to maximize its benefit. Currently, the medical prescription is at a transitional stage between paper and web, and to adapt a traditional process to the new electronic era offers both opportunities and challenges The studies in the thesis have shown that the exposure of prescribed drugs in the general population has increased considerably over three decades. The risk of receiving potentially interacting drugs was also strongly correlated to the concomitant use of multiple drugs, polypharmacy. The pronounced increase in polypharmacy over time constitutes a growing reason for prescribers and pharmacists to be aware of drug interactions. Still, there were relatively few severe potential drug interactions. Recently established national prescription registers should be evaluated for drug interaction vigilance, both clinically and epidemiologically. The Swedish National Pharmacy Register provides prescription dispensing information for the majority of the population. The medication history in the register may be accessed online to improve drug utilization, by registered individuals, prescribers, and pharmacists in a safe and secure way. Lack of widespread secure digital signatures in healthcare may delay general availability. With a relatively high prevalence of dispensed drugs in the population, the National Pharmacy Register seems justified in evaluating individual medication history. With a majority of prescriptions transferred as ePrescriptions, the detected increased risk for prescription errors warrants quality improvement, if the full potential of ePrescriptions is to be fulfilled. The main conclusion of the studies was that ePrescribing with communication of prescribed drug information, storing and retrieving dispensed drug information, offers new opportunities for clinical and scientific

A identificação de reações adversas a medicamentos (RAM) nos hospitais constitui uma importante medida da morbidade associada a medicamentos e de seu ônus sobre o sistema de saúde. Este estudo observacional não intervencionista teve por objetivo avaliar a incidência de RAM em pacientes hospitalizados, as características clínicas das reações e fatores de risco associados. Foram avaliados 472 pacientes de cinco clínicas do Hospital das Clínicas da FMUSP (Clínica Médica, Cirurgia Geral, Neurologia, Geriatria, Alergia e Imunologia Clínica), com formação de coorte prospectiva, analisando as características demográficas, comorbidades, número de medicações utilizadas antes e durante a hospitalização e tempo de internação. A prevalência das RAM foi de 1,7% e a incidência geral de RAM foi 16,2%, variando conforme a clínica avaliada, sendo maior na Clínica Médica (30%). As reações mais frequentes foram as do tipo A, predominando as manifestações gastrointestinais. A maior parte das reações foi classificada de gravidade moderada. O maior número de medicações utilizadas por paciente, insuficiência renal crônica e tempo de internação foram fatores de risco para RAM, porém não houve associação das reações com idade avançada. Antecedente de RAM anterior à internação foi identificado como fator de proteção. A incidência de reações de hipersensibilidade a medicamentos (RHM) foi de 3,2%, com maior número de medicações utilizadas por paciente como único fator de risco isolado, sem associação com as clínicas avaliadas ou gênero dos pacientes. As medicações mais associadas às RAM e RHM foram os antibióticos, opióides e contrastes iodados. Os medicamentos mais prescritos foram os sintomáticos. O estudo concluiu que as RAM são frequentes e potencialmente evitáveis. O conhecimento da incidência e dos fatores associados pode estimular a prevenção. A prescrição de medicações para pacientes internados deve ser mais criteriosa, especialmente para os mais susceptíveis, evitando a polifarmácia / The detection of adverse drug reactions (ADRs) in hospitalized patients is an important measure of morbidity associated with drugs and its burden on the health system. The objective of this non-interventionist observational study was to assess the incidence of ADRs in hospitalized patients, the clinical characteristics of reactions and associated risk factors. We evaluated 472 patients from five medical specialties of the Hospital das Clínicas-FMUSP (Internal Medicine, General Surgery, Neurology, Geriatrics, Clinical Immunology and Allergy). We performed a prospective cohort, analyzing the demographics features, comorbidities, number of medications used before and during hospitalization and length of stay in the hospital. The prevalence of ADRs was 1.7% and the overall incidence of ADRs was 16.2%, varying according to the specialty assessed, higher in the Internal Medicine (30%). The most frequent reactions were type A, with gastrointestinal manifestations being the most frequent. Most of the reactions were classified as moderate in severity. The greater number of drugs used, chronic renal failure and longer hospital stays were risk factors for ADRs, but there was no association between reactions and age. History of previous ADRs to admission was identified as a protective factor. The incidence of hypersensitivity drug reactions (HDRs) was 3.2%, with the greater number of medications used per patient as the sole isolated risk factor, without association with specialty or patient\'s gender. The main medications associated with ADRs and HDRs were antibiotics, opioids and iodinated contrast media. The most commonly prescribed medications were symptomatic ones. The study concluded that the ADRs are frequent and potentially preventable. Knowledge of the incidence and associated factors can stimulate prevention. The pharmacotherapy of in-patients should be more careful, especially for the more susceptible patients, avoiding polypharmacy

Social workers are trained during the course of their education to work with the elderly and to understand the various dynamics of aging. These professionals also receive education on substance abuse and how to assess clients as well as link them to appropriate supportive services. How can social workers be more inclined to effectively treat the elderly substance abuser? What are, if any, special considerations a social worker should be aware of when working with the geriatric population? What treatment modalities seem to be more effective with the elderly client? This study utilized a qualitative analysis consisting of interviews with eight clinicians who specialize in the area of addiction treatment amongst the aging population. The purpose of this study was to gain insight and knowledge that can be used to promote social worker awareness of elderly substance abuse as well as the identification of effective addiction treatment methods in the field of gerontological social work. The findings of this study will impact future social work practice, policy and research in the areas of education, treatment, and advocacy for the aging and substance abuse populations. Keywords: gerontology, substance abuse, aging, polypharmacy, interventions

Background: Multimorbidity is defined as suffering from coexistent chronic conditions. Multimorbid patients demand highly complex patient-centered care which often includes polypharmacy, taking an average of six different drugs per day. Adverse drug reactions, adverse drug events and medication errors are all potential consequences of polypharmacy. Our study aims to detect the status quo of the health care situation in Saxony’s general practices for multimorbid patients receiving multiple medications. We will identify the most common clinical profiles as well as documented adverse drug events and reactions that occur during the treatment of patients receiving multiple medications. We will focus on exploring the motives of general practitioners for the prescription of selected drugs in individual cases where there is evidence of potential drug-drug-interactions and potentially inappropriate medications in elderly patients. Furthermore, the study will explore general practitioners’ opinions on delegation of skills to other health professions to support medical care and monitoring of patients receiving multiple medications. Methods/design: This is a retrospective cross sectional study using mixed methods. Socio-demographic data as well as diagnoses, medication regimens and clinically important events will be analyzed retrospectively using general practitioners documentation in patients’ records. Based on these data, short vignettes will be generated and discussed by general practitioners in qualitative telephone interviews. Discussion: To be able to improve outpatient health care management for patients receiving multiple medications, the current status quo of care, risk factors for deficient treatment and characteristics of concerned patients must be investigated. Furthermore, it is necessary to understand the physicians’ decision making process regarding treatment.

Background Polypharmacy is often prescribed for bipolar disorder, yet medication non-adherence remains a serious problem. This study investigated the regularity in the daily dosage taken of mood stabilizers and second generation antipsychotics. Methods Daily self-reported data on medications taken and mood were available from 241 patients with a diagnosis of bipolar disorder who received treatment as usual. Patients who took the same mood stabilizer or second generation antipsychotic for ≥ 100 days were included. Approximate entropy was used to determine serial regularity in daily dosage taken. Generalized estimating equations were used to estimate if demographic or clinical variables were associated with regularity. Results There were 422 analysis periods available from the 241 patients. Patients took drugs on 84.4% of days. Considerable irregularity was found, mostly due to single-day omissions and dosage changes. Drug holidays (missing 3 or more consecutive days) were found in 35.8% of the analysis periods. Irregularity was associated with an increasing total number of psychotropic drugs taken (p = 0.009), the pill burden (p = 0.026), and the percent of days depressed (p = 0.049). Conclusion Despite low missing percent of days, daily drug dosage may be irregular primarily due to single day omissions and dosage changes. Drug holidays are common. Physicians should expect to see partial adherence in clinical practice, especially with complex drug regimens. Daily dosage irregularity may impact the continuity of drug action, contribute to individual variation in treatment response, and needs further study.