Baclofen overdose treated with continuous venovenous hemofiltration.

PURPOSE: Overdose with baclofen, a derivative of the inhibitory neurotransmitter γ-aminobutyric acid, may lead to severe respiratory and central nervous system depression and can be life-threatening. Prolonged half-lives of baclofen, of up to 34 h, have been reported in patients after overdose. Hemodialysis has proven to be a successful approach to improve clearance of baclofen, but the value of continuous venovenous hemofiltration (CVVH) is unclear. We applied CVVH in a patient with acute baclofen overdose. METHODS: Pharmacokinetic measurements of baclofen in serum and hemofiltrate were made at six time points after hospital admission. Baclofen concentration-time data were analyzed using non-compartmental methods, and the relative contribution of clearance by hemofiltration to total baclofen clearance was calculated. RESULTS: Baclofen concentrations in serum varied between 1.81 and 0.05 mg/L. Concentrations of baclofen in hemofiltrate were within the same range (between 0.74 and 0.05 mg/L), and the elimination half-life during hemofiltration was estimated at 4.8 h. Total clearance and clearance via hemofiltration were estimated at 6.6 and 2.4 L/h, indicating that clearance could be increased by approximately 57 % by applying hemofiltration. CONCLUSIONS: The presented case demonstrates the usefulness of CVVH in the treatment of baclofen overdose and indicates that CVVH can be used as an alternative to hemodialysis in patients with overdose of baclofen.

Discrepancies in reported drug use in geriatric outpatients: relevance to adverse events and drug-drug interactions.

BACKGROUND: Increased age is associated with polypharmacy. Polypharmacy is a risk factor for severe adverse drug reactions (ADRs) and is associated with an increased risk of mortality. OBJECTIVES: The main goal of the current study was to describe the frequency and relevancy of discrepancies in drug use in Dutch geriatric outpatients as reported by the patients and their caregivers, documented by the referring general practitioner (GP), and registered by the public pharmacy. The frequency of medication discrepancy adverse patient events (MDAPEs) was also recorded. In addition, possible contributing factors-such as increasing age, cognitive status and depressive symptoms, the number of medications used, the number of physicians visited by the patient, and the presence of a caregiver to supervise medication use-were studied. METHODS: This was a prospective descriptive study conducted at the geriatric outpatient clinic of a teaching hospital. Between January 1 and May 1, 2005, consecutive patients were included if they were aged >65 years, reported use of > or =1 medication, and if they could understand the goals and consequences of participating in the study. The medications described by geriatric patients and their caregivers were compared with the drugs listed by their GP. The pharmacies of the referred patients were asked to send a description of the drugs distributed in the 6 months preceding the patient's visit to the geriatric outpatient clinic. The classification of ADRs and undertreatment as clinically relevant was done by study investigators who were blinded for the presence of discrepancy. RESULTS: A total of 120 outpatients were included. The mean (SD) age of the study patients was 82.3 (6.8) years; 71.7% were women. Of the 120 patients, 113 patients (94.2%) reported taking >1 drug and 88 (73.3%) were prescribed > or =4 drugs. At least 1 discrepancy between the medication lists of the patients, GP, or pharmacy was present in 104 of the 120 patients (86.7%). In 90 patients (75.0%), there was > or =1 discrepancy between the medication reported by the patient and the GP. Patients with > or =1 discrepancy reported taking a higher mean number of drugs and had more prescribing physicians in addition to their GP. Twenty-nine patients (24.2%) experienced an MDAPE involving the use of drugs the GP had not correctly described in the letter of referral. The pharmacy was unaware of the use of medication involved in an MDAPE in 2 patients. CONCLUSIONS: Geriatricians should assume that the medication lists supplied by GPs are incomplete or incorrect, and be aware that in approximately 25% of patients, symptoms may be caused by medication use inaccurately described in the referral. Reports by the community pharmacy may supply valuable additional information. Because there are also discrepancies between patients and pharmacies, medication use from a database-with data from prescribing physicians and pharmacy systems-will still have to be confirmed by the patient.

Drug-drug interactions in a geriatric outpatient cohort: prevalence and relevance.

BACKGROUND: The prevalence of drug-drug interactions (DDIs) in a geriatric population may be high because of polypharmacy. However, wide variance in the clinical relevance of these interactions has been shown. OBJECTIVES: To explore whether adverse drug reactions (ADRs) as a result of DDIs can be identified by clinical evaluation, to describe the prevalence of ADRs and diminished drug effectiveness as a result of DDIs and to verify whether the top ten most frequent potential DDIs known to public pharmacies are of primary importance in geriatric outpatients in the Netherlands. METHOD: All adverse events classified by the Naranjo algorithm as being a possible ADR and drug combinations resulting in diminished drug effectiveness were identified prospectively in 807 geriatric outpatients (mean age 81 years) at their first visit. The setting was a diagnostic day clinic. The Medication Appropriateness Index (MAI) and Beers criteria were used to evaluate drug use and identify possible DDIs. The ten most frequent potential interactions, according to a 1997 national database of public pharmacies ('Top Ten') in the Netherlands, and possible adverse events as a result of other interactions, were described. The effects of changes in medication regimen were recorded by checking the medical records. RESULTS: In 300 patients (44.5% of the 674 patients taking more than one drug), 398 potential DDIs were identified. In 172 (25.5%) of patients taking more than one drug, drug combinations were identified that were responsible for at least one ADR or which possibly resulted in reduced effectiveness of therapy. Eighty-four of the 158 possible ADRs resulting from enhanced action of drugs forming combinations listed in the 'Top Ten' were seen in 73 patients. Only four DDIs resulting in less effective therapy that involved drug combinations in the 'Top Ten' were identified. Changes in drug regimens pertaining to possible interactions were proposed or put into effect in 111 of the 172 (65%) patients with possible DDIs. Sixty-one (55%) of these patients returned for follow-up. Of these, 49 (80%) were shown to have improved after changes were made to their medication regimen. CONCLUSION: In this study, nearly half of the geriatric outpatients attending a diagnostic day clinic who were taking more than one drug were candidates for DDIs. One-quarter of these patients were found to have possible adverse events or diminished treatment effectiveness that may have been at least partly caused by these DDIs. These potential interactions can be identified through clinical evaluation. In the majority of patients (99 of 172) the potential interactions resulting in possible ADRs or diminished effectiveness were not present in the 'Top Ten' interactions described by a national database of public pharmacies, a finding that emphasizes that the particular characteristics of geriatric patients (e.g. frequent psychiatric co-morbidities) need to be considered when evaluating their drug use. At least 7% of all patients taking more than one drug, and 80% of those with possible drug interactions whose drug regimen was adjusted, benefited from changes made to their drug regimens.

Evaluation of pharmacotherapy in geriatric patients after performing complete geriatric assessment at a diagnostic day clinic.

BACKGROUND: Elderly patients often take multiple drugs. It is known that polypharmacy, i.e. use of five or more drugs, may lead to drug interactions and adverse events. However, undertreatment of conditions or illnesses is also a concern in geriatric patients. A centralised review of both diagnoses and medication may play a key role in optimising pharmacotherapy in geriatric patients. The aims of this study were to evaluate the quality and appropriateness of medication after performing a complete geriatric assessment (CGA) and medication review at a diagnostic geriatric day clinic, to investigate reasons for drug changes, and to determine whether medication review leads to a reduction in the number of drugs used. METHODS: A chart review was performed in 702 patients (mean age 82.0 years, range 57.1-104.1 years) who underwent a CGA at a diagnostic geriatric day clinic. Medication at admission, changes in medication and reasons for changes were noted. RESULTS: Vitamins, for example folic acid and vitamin B(12) (cyanocobalamin), and trimethoprim for urinary tract infections were the most frequently started medications after CGA and medication review. The number of drugs used was reduced in only a minority of patients (11.7%); reasons for discontinuation were a diagnosis that was no longer relevant (38.8%), adverse events (33.2%) and identification of better pharmacotherapeutic options (22.0%). In 69.2% of the cases a new diagnosis was the reason for starting a new medication, followed by osteoporosis prophylaxis (15.0%) and improvement in pharmacotherapy (10.6%). At admission, patients were taking a mean number of 4.6 drugs (range 0-17). A mean of 0.8 drugs (range from reduction of 5 to addition of 7) had been added per patient, resulting in a mean number of 5.4 (range 0-18) prescribed drugs at discharge. CONCLUSION: Evaluation of medication in patients after performing CGA at the geriatric day clinic investigated resulted in relevant medication changes. The main reason for prescribing new drugs was a new diagnosis. Absence of a relevant medical indication was the main reason for stopping drugs. CGA and medication review resulted in a mean net addition of 0.8 drugs per patient.

Drug interactions between antiretroviral drugs and comedicated agents.

HIV-infected individuals usually receive a wide variety of drugs in addition to their antiretroviral drug regimen. Since both non-nucleoside reverse transcriptase inhibitors and protease inhibitors are extensively metabolised by the cytochrome P450 system, there is a considerable potential for pharmacokinetic drug interactions when they are administered concomitantly with other drugs metabolised via the same pathway. In addition, protease inhibitors are substrates as well as inhibitors of the drug transporter P-glycoprotein, which also can result in pharmacokinetic drug interactions. The nucleoside reverse transcriptase inhibitors are predominantly excreted by the renal system and may also give rise to interactions. This review will discuss the pharmacokinetics of the different classes of antiretroviral drugs and the mechanisms by which drug interactions can occur. Furthermore, a literature overview of drug interactions is given, including the following items when available: coadministered agent and dosage, type of study that is performed to study the drug interaction, the subjects involved and, if specified, the type of subjects (healthy volunteers, HIV-infected individuals, sex), antiretroviral drug(s) and dosage, interaction mechanism, the effect and if possible the magnitude of interaction, comments, advice on what to do when the interaction occurs or how to avoid it, and references. This discussion of the different mechanisms of drug interactions, and the accompanying overview of data, will assist in providing optimal care to HIV-infected patients.

Pharmacotherapy of Hospitalised HIV-Infected Patients in a General Hospital during 1990, 1997 and 2001.

OBJECTIVE: To describe the changes over time in drug therapy (antiretroviral as well as co-administered drugs) in HIV-infected patients who required hospitalisation during the period 1990-2001. In addition, we wanted to evaluate and compare the characteristics of these patients. DESIGN/SETTING: Retrospective review of hospitalisations of HIV-infected patients in a general hospital. RESULTS: During specified periods in 1990, 1997 and 2001, 22 patients out of 130 outpatients, 29 out of 394 outpatients, and 19 out of 570 outpatients, respectively, who were treated at the outpatient clinic were admitted 30, 38 and 27 times, respectively. The mean duration of these hospitalisations was 18.8, 14.2 and 16.7 days, respectively. The percentage of women and the mean age of the hospitalised patients increased over the studied time period. AIDS-related diagnoses decreased when comparing 1997 with 2001. The type of co-administered drugs of patients who required hospitalisation was fairly stable, but the total volume (defined as the mean volume of drugs per patient per bed-day) increased dramatically from 5.3 in 1990 to 6.8 in 1997 and to 15.5 in 2001. Dual and triple antiretroviral therapy decreased and became quadruple or greater therapy when 1997 and 2001 were compared. In addition, the number of hospitalised patients not treated with antiretroviral drugs increased from 1997 to 2001. CONCLUSION: The incidence of hospital admissions decreased but the volume of co-administered drugs increased from 1990 to 2001, suggesting extensive co-morbidity in the patients who still require hospitalisation.

Lethal morphine intoxication in a patient with a sickle cell crisis and renal impairment: case report and a review of the literature.

Morphine-6-glucuronide, the active metabolite of morphine, and to a lesser extent morphine itself are known to accumulate in patients with renal failure. A number of cases on non-lethal morphine toxicity in patients with renal impairment report high plasma concentrations of morphine-6-glucuronide, suggesting that this metabolite achieves sufficiently high brain concentrations to cause long-lasting respiratory depression, despite its poor central nervous system penetration. We report a lethal morphine intoxication in a 61-year-old man with sickle cell disease and renal impairment, and we measured concentrations of morphine and morphine-6-glucuronide in blood, brain and cerebrospinal fluid. There were no measurable concentrations of morphine-6-glucuronide in cerebrospinal fluid or brain tissue, despite high blood concentrations. In contrast, the relatively high morphine concentration in the brain suggests that morphine itself was responsible for the cardiorespiratory arrest in this patient. Given the fatal outcome, we recommend to avoid repeated or continuous morphine administration in renal failure.

Changes in under-treatment after comprehensive geriatric assessment: an observational study.

BACKGROUND: Under-treatment is frequently present in geriatric patients. Because this patient group often suffer from multiple diseases, polypharmacy (defined as the concomitant chronic use of five or more drugs) and contraindications to indicated drugs may also frequently be present. OBJECTIVE: To describe the prevalence of under-treatment with respect to frequently indicated medications before and after comprehensive geriatric assessment (CGA) and the prevalence of contraindications to these medications. PATIENTS AND METHODS: The geriatric outpatients evaluated in this study had previously been included in a prospective descriptive study conducted in 2004. Demographic data, medical history, co-morbidity and medication use and changes were documented. The absence of drugs indicated for frequently under-treated conditions before and after CGA was compared. Under-treatment was defined as omission of drug therapy indicated for the treatment or prevention of 13 established diseases or conditions known to be frequently under-treated. Co-morbid conditions were independently classified by two geriatricians, who determined whether or not a condition represented a contraindication to use of these drugs. RESULTS: In 2004, 807 geriatric outpatients were referred for CGA. Of these, 548 patients had at least one of the 13 selected diseases or conditions. Thirty-two of these patients were excluded from the analysis, leaving 516 patients. Before CGA, 170 of these patients were under-treated (32.9%); after CGA, 115 patients (22.3%) were under-treated. Contraindications were present in 102 of the patients (19.8%) and were more frequent in under-treated patients. After CGA, mean drug use and the prevalence of polypharmacy increased. Although 393 drugs were discontinued after CGA, the overall number of drugs used increased from 3177 before CGA to 3424 after CGA. Five times more drugs were initiated for a new diagnosis than for correction of under-treatment. CONCLUSIONS: Under-treatment is significantly reduced after CGA. Patients with contraindications to indicated medicines are more frequently under-treated. CGA leads to an increase in polypharmacy, mainly because of new conditions being diagnosed and despite frequent discontinuation of medications.

Contraindications for anticoagulation in older patients with atrial fibrillation; a narrative review.

BACKGROUND: Oral anticoagulation (OAC) is the most effective treatment to prevent strokes in patients with atrial fibrillation (AF). Many older patients are not prescribed OAC. OBJECTIVE: To explore which co-morbid conditions in older patients with AF have been associated with under-treatment with OAC, or were used as exclusion criteria for trials, or have been associated with increased risk of bleeding. METHODS: A Pubmed search was conducted with the terms elderly, atrial fibrillation, stroke risk, bleeding risk, intracranial haemorrhage, cognition, fall risk, renal dysfunction, alcohol abuse, malignancy, polypharmacy, NSAID, under-treatment, under-use and under-prescription. RESULTS: Higher age is associated with under-treatment. Patients with a higher risk of stroke show higher rates of bleeding complications. The associations of bleeding rates with possible contraindications are inconsistent. DISCUSSION: Published bleeding rates reflect selection bias, describing mainly relatively healthy older patients. The use of stratification schemes for stroke risk and for bleeding risk will have to be implemented. CONCLUSION: The decision to prescribe OAC in older patients with AF remains a challenging task since bleeding risk is difficult to estimate reliably. Stratification schemes may be helpful.

Reasons for undertreatment with oral anticoagulants in frail geriatric outpatients with atrial fibrillation: a prospective, descriptive study.

OBJECTIVES: The main aims of the study were to explore whether oral anticoagulation (OAC) for atrial fibrillation (AF) in geriatric outpatients is prescribed in accordance with international (American College of Cardiology/American Heart Association/European Society of Cardiology [ACC/AHA/ESC]) and Dutch national guidelines for the general practitioner (GP) and to identify whether age and selected co-morbid conditions are associated with undertreatment. As a secondary objective, we wanted to establish how many patients discontinue OAC because of major bleeding. METHODS: In 2004, at the first visit of all patients to the geriatric day clinic of the Slotervaart Hospital in Amsterdam, the Netherlands, demographic data, Mini-Mental State Examination score, medical history, Charlson Comorbidity Index score, and data on medication use and changes were documented. The presence of AF was established by assessment of medical history information obtained by the GP, the history taken from patients and their caregivers, and the results of clinical evaluation, including ECG findings. Associations between the use of OAC, demographic data and co-morbid conditions registered in the Dutch NHG (Nederlands Huisartsen Genootschap [Dutch College of General Practitioners]) standard for GPs as risk factors for stroke or contraindications to the use of OAC were analysed. The reasons for discontinuing OAC were assessed after 4 years by requesting the information from the anticoagulation services or the GP. RESULTS: At the time of the initial visit, 17.5% of the 807 outpatients had chronic AF (n = 135) or were known to have paroxysmal AF (n = 6). The mean age of the 141 patients in this cohort was 84.3 years (SD 6.2 years). Co-morbid conditions increasing the risk of stroke were present in 129 patients (91.5%). Contraindications to the use of OAC were observed in 118 patients (83.7%). Of the 116 patients with AF in their history before their visit, 57.8% were being treated with OAC at the time of their visit. After comprehensive geriatric assessment, 73 (51.8%) of the 141 patients with chronic or paroxysmal AF were continued on OAC. Of the 141 patients with chronic or paroxysmal AF, 110 (78.0%) had both extra stroke risk factors and contraindications to the use of OAC. Only increasing age was significantly and independently associated with not being prescribed anticoagulants (p < 0.001). At the 4-year follow-up, OAC had been discontinued in 5.5% of patients because of major bleeding; three patients (4.1%) taking OAC had died as a result of major bleeding, and one other patient had discontinued treatment because of a major, non-lethal bleeding episode. CONCLUSION: Applying the NHG standard for appropriate prescription, and disregarding age as a risk factor or contraindication, in this population, 14 of 141 patients (9.9%) were inappropriately prescribed OAC, salicylates or no prophylaxis. Since only patient age was associated with not prescribing OAC in this study, higher age still seems to be considered the most important contraindication to anticoagulation therapy. Implementation of better models for stratifying bleeding risk in the frail elderly is needed. After 4 years, the cumulative rate of bleeding causing discontinuation of anticoagulation therapy in this usual-care study of frail older patients was not alarmingly higher than in other usual-care studies.

Do geriatric outpatients adhere to medication changes advised after assessment? An exploratory pilot study.

BACKGROUND: The most frequent intervention after Comprehensive Geriatric Assessment (CGA) is adjustment of medications. Adherence to recommendations is often incomplete. Patients at high risk of non-adherence should be identified. OBJECTIVE: To explore if changes in drug-use after CGA are carried out by the patient. To identify factors influencing non-adherence. METHODS: Co-morbidity and medication use were recorded. Patients, and when cognitively impaired, a caregiver, were questioned about advised changes. Drug-use before and after CGA was assessed. Patients were asked whether they would discontinue their drugs either with or without consulting their physician. Univariate logistic regression analysis to identify factors influencing non-adherence, was performed with SPSS. RESULTS: Forty patients were included. Of the changes in medication advised, 90 % were reported to be carried out. 65 % of the patients were compliant. Only the presence of a caregiver was associated with reported complete adherence to drug therapy. Most patients can't describe for how long they will have to continue taking the drugs that are prescribed to them. CONCLUSION: Most geriatric patients carry out changes in medication made after CGA. Supervision by caregivers may explain a high rate of reported adherence despite the presence of polypharmacy and cognitive decline. PRACTICE IMPLICATIONS: In the absence of caregivers special attention should be paid to adherence to medication changes. Information about intended duration of drug therapy should be improved.

Treatment of hypertension in an elderly outpatient population in the Netherlands.

BACKGROUND: The treatment of older patients with hypertension has been controversial-in addition to uncertainty regarding appropriate blood pressure (BP) targets in the very old, there are concerns that excessive BP lowering could result in adverse events such as falls, stroke, and cognitive problems. The Hypertension in the Very Elderly Trial (HYVET), however, found that lowering BP in patients aged > or =80 years was associated with decreased morbidity and mortality. OBJECTIVE: This study compared the findings of HYVET with data from a population of elderly outpatients with hypertension in a clinical practice setting. METHODS: This was a retrospective study of prospectively collected data from patients aged > or =80 years with a history of hypertension who visited a geriatric diagnostic day clinic in the Netherlands in 2004. The data were analyzed to determine how many patients were being prescribed antihypertensive medication, how many would have been eligible for HYVET, how many achieved adequate BP control, and whether reaching BP goals was associated with the number and type of antihypertensive medications received or with eligibility for HYVET. RESULTS: During 2004, 518 patients aged > or =80 years visited the geriatric diagnostic day clinic, of whom 147 met the criteria for inclusion in this study. One hundred forty-one patients (95.9%) were receiving antihypertensive medication, although only 52 (35.4%) would have been eligible for HYVET. Dementia, which was an exclusion criterion in HYVET, was the major reason for ineligibility (70 [47.6%]). Greater proportions of patients in this study had comorbidities compared with the HYVET population (stroke: 22.4% vs 6.7%, respectively; myocardial infarction: 7.5% vs 3.1%; heart failure: 11.6% vs 2.9%; diabetes mellitus: 21.1% vs 6.8%). At the time of the clinic visit, 50.3% of patients had adequate BP control, as defined in HYVET (systolic BP <150 mm Hg and diastolic BP <80 mm Hg). Levels of BP control were similar in patients who would and would not have been ineligible for HYVET. Only the mean (SD) number of antihypertensive medications received was significantly associated with the achievement of BP control compared with failure to achieve adequate BP control (2.2 [1.0] vs 1.8 [1.1], respectively; P < 0.05). CONCLUSIONS: Based on the findings of this study, the benefits of treating elderly patients with hypertension in clinical practice may be lower than those reported by HYVET. The study results support the current recommendation that all patients with hypertension should be treated with >1 antihypertensive medication if adequate control is not achieved at low doses of a single medication.

The effect of admission to a geriatric ward on medication use: 2002 versus 1985.

PURPOSE: To investigate the changes in pharmacotherapy of patients during and after admission to a geriatric ward in 2002 and to investigate if this goes along with reduction of drugs. To describe the differences of the admitted patients and their medication in 2002 compared to 1985. METHODS: Included patients were admitted to the geriatric ward of a general hospital in the Netherlands during 2002 (n = 258, mean age 84.2 years). Medication at admission, during admission and at discharge were described after retrospective reviewing of medical charts. A comparable study was performed at the same ward in 1985. RESULTS: In 2002, most frequently used medication at admission was acetylsalicylic acid (30.2%). Pantoprazole was during admission used in 38.8% of patients and at discharge in 31.8%. Folic acid that was at admission used by 11.6% of patients was at discharge increased to 23.4%. At discharge, vitamin D was used in 21.5% of patients, whereas lisinopril was used in 17.8% of patients. Both in 1985 and 2002 vitamins were added and use of antibiotics was increased during admission. A mean addition of 1.0 drug in 1985 and of 0.7 drugs in 2002 was observed. CONCLUSIONS: Geriatric hospital admission resulted both in 1985 and 2002 in addition of medication. In both periods reductions in medication were nullified by addition of medication for reason of therapy optimisation. Compared to 1985 admitted patients receive more medication resulting from new insights into pharmacotherapy and more use of preventive medicine.

Discontinuation of rivastigmine in routine clinical practice.

BACKGROUND: Rivastigmine is used for symptomatic treatment of mild-to-moderately severe Alzheimer's Dementia (AD). We investigated the frequency of and reasons for rivastigmine discontinuation in clinical practice and possible predictive factors for discontinuation within the first six months after starting therapy. METHODS: A retrospective cohort study was performed in rivastigmine users, who started therapy in a naturalistic setting. A nurse supported a part of the studied cohort, as this was introduced during the study period. Reasons for discontinuation were investigated, including therapy discontinuation if the Maximum Achieved Dose (MAD) was below 6 mg daily. Predictors of discontinuation within the first half year were investigated by logistic regression analysis. RESULTS: Baseline Mini-Mental-State-Examination (MMSE) of included patients (n = 154) was 20.1, mean age was 78.4 years and 70% was female. Within 6 months, 61 users (39.6%) discontinued therapy, primarily (59.0%) for adverse events. Thereafter, the main reason for discontinuation was non-response according to clinimetrics. A MAD during the titration phase of 1.5-4.5 mg/day and absence of nurse support are significantly related to discontinuation within 6 months. CONCLUSIONS: Rivastigmine is primarily discontinued within the first six months for intolerable adverse events and thereafter mainly for ongoing deterioration. A MAD of 1.5-4.5 mg/day and the absence of nurse support are independently related to discontinuation of rivastigmine within the initial 6 months.

Discrepancies between medical and pharmacy records for patients on anti-HIV drugs.

OBJECTIVE: To compare and evaluate drug notations in outpatient medical records and in pharmacy records in a cohort of HIV-1-infected patients treated with antiretroviral drugs. METHODS: Data on 103 patients were obtained from January 1, 1998, through December 31, 1999, by medical chart review and collection of pharmacy records. Two analyses were performed. First, antiretroviral drugs and comedication in the pharmacy records were documented and compared with their appearance in the outpatient medical records. Second, a detailed comparison was performed at 5 time points during the study period for the antiretroviral drugs. Generic name, formulation, strength, and frequency of dosing as registered in the outpatient medical records were compared with those registered in the pharmacy records. RESULTS: Total drug dispensation was 1607 (366 and 1241 antiretroviral drugs and comedication, respectively). The first screening resulted in a total discrepancy of 55.1% (n = 885), of which 97.1% (n = 859) was attributed to the comedication and 2.9% (n = 26) to the antiretroviral drugs. The discrepancy for the antiretroviral drugs at the specific time points ranged from 5.1% to 12.6% when the generic name only was used, and from 7.1% to 17% when formulation, strength, and frequency of dosing were also taken into account. CONCLUSIONS: The observed discrepancy between outpatient medical records and pharmacy records mainly concerns the comedication. For the antiretroviral drugs fewer, but still substantial, discrepancies were observed. These results indicate that full exchange of information conceming drug use in this population between general practitioners and specialists (infectious disease) is lacking.