Transdermal clonidine as an adjunct to enalapril: an evaluation of efficacy and patient compliance

Impact of dose frequency on compliance and health outcomes: a literature review (1966-2006)

In order for treatments to be effective, patients must be compliant with their medication regimens. Currently, patient compliance is seen as one of the most challenging issues in treating patients with chronic diseases. Studies in which dose frequency has been changed have been reviewed across several different diseases to examine the impact of a change in dose frequency on compliance and health outcomes, as well as efficacy and tolerability. In general, reducing dose frequency may improve medication compliance and effectiveness, and reduce adverse events, while possibly reducing healthcare costs. Suggestions for future research have been presented, including a need to measure compliance with injectable formulations and a standardized definition of compliance.

Cultural adaptation of a compliance questionnaire for patients with rheumatoid arthritis to a Korean version

BACKGROUND/AIMS

The Compliance Questionnaire-Rheumatology (CQR) is a validated scale to evaluate patient compliance for anti-rheumatic medications. We developed a Korean version of the CQR (KCQR) and confirmed its reliability and validity.

METHODS

We prepared the KCQR by translating and back-translating the original CQR with modifications to adapt it to Korean culture. Fifty Korean patients with rheumatoid arthritis (RA) were enrolled in this study. The test-retest reliability of the KCQR was evaluated at a 2-week interval using the intraclass correlation coefficient (ICC). The validity of the KCQR was assessed by identifying associations between KCQR scores and patient compliance, measured using pharmacy refill data.

RESULTS

The reliability of the KCQR was adequate, with an ICC of 0.71 for test-retest reliability. With respect to validity, the summed score of the weighted KCQR showed a significant correlation with pharmacy refill data (r² = 0.57) on multiple regression analysis.

CONCLUSIONS

Our results indicate that the KCQR is a reliable, valid instrument to evaluate compliance of Korean patients for RA medications.

Compliance with the treatment of hypertension: the potential of combination therapy

Patient adherence to antihypertensive medication is vital to ensure the successful treatment of hypertension. Low levels of adherence to and persistence with prescribed therapy are major factors leading to the current poor rates of blood pressure control among patients with hypertension. There are many reasons for nonadherence to therapy including patient-, physician-, and therapy-related factors. Poor tolerability has a detrimental effect on adherence, therefore reducing the apparent effectiveness of agents with dose-dependent side effects. Various effective combination therapies are recommended by current guidelines, eg, beta-blocker plus calcium channel blocker (CCB), angiotensin receptor blocker (ARB) plus thiazide diuretic, angiotensin-converting enzyme (ACE) inhibitor plus thiazide diuretic, CCB plus thiazide diuretic, ACE inhibitor plus CCB, and ARB plus CCB, and these have the potential to increase adherence to therapy by combining a favorable tolerability profile with once-daily dosing.

All that glisters is not gold: a comparison of electronic monitoring versus filled prescriptions--an observational study

BACKGROUND

Poor compliance with antihypertensive medication is assumed to be an important reason for unsatisfactory control of blood pressure. Poor compliance is difficult to detect. Each method of measuring compliance has its own strengths and weaknesses. The aim of the present study was to compare patient compliance with antihypertensive drugs as measured by two methods, electronic monitoring versus refill compliance.

METHODS

161 patients with a diagnosis of hypertension for at least a year prior to inclusion, and inadequate blood pressure control (systolic blood pressure > or = 160 mmHg and/or diastolic blood pressure > or = 95 mmHg) despite the use of antihypertensive drugs, were included. Patients' pharmacy records from 12 months prior to inclusion were obtained. Refill compliance was calculated as the number of days for which the pills were prescribed divided by the total number of days in this period. After inclusion compliance was measured with an electronic monitor that records time and date of each opening of the pillbox. Agreement between both compliance measures was calculated using Spearman's correlation coefficient and Cohen's kappa coefficient.

RESULTS

There was very little agreement between the two measures. Whereas refill compliance showed a large range of values, compliance as measured by electronic monitoring was high in almost all patients with estimates between 90% and 100%. Cohen's kappa coefficient was 0.005.

CONCLUSION

While electronic monitoring is often considered to be the gold standard for compliance measurements, our results suggest that a short-term electronic monitoring period with the patient being aware of electronic monitoring is probably insufficient to obtain valid compliance data. We conclude that there is a strong need for more studies that explore the effect of electronic monitoring on patient's compliance.

Transdermal clonidine: therapeutic considerations

Transdermal clonidine was approved by the US Food and Drug Administration in 1984 for the treatment of mild-to-moderate hypertension alone or in combination with a diuretic. Clonidine is released from the patch at a constant rate and thus displays a pharmacokinetic pattern not dissimilar to that of infusion therapy. Transdermal clonidine, like oral clonidine, is effective first- or second-line therapy for most forms of hypertension. More recently, transdermal clonidine has found alternative uses in the areas of smoking cessation, posttraumatic stress disorder, menopausal hot flashes, and alcohol and opiate withdrawal syndromes. The not infrequent development of a dermatitis, together with a substantially greater cost than oral clonidine, have been the major undoings for transdermal clonidine.

Drug delivery systems improve pharmaceutical profile and facilitate medication adherence

Innovations in dosage forms and dose delivery systems across a wide range of medications offer substantial clinical advantages, including reduced dosing frequency and improved patient adherence; minimized fluctuation of drug concentrations and maintenance of blood levels within a desired range; localized drug delivery; and the potential for reduced adverse effects and increased safety. The advent of new large-molecule drugs for previously untreatable or only partially treatable diseases is stimulating the development of suitable delivery systems for these agents. Although advanced formulations may be more expensive than conventional dosage forms, they often have a more favorable pharmacologic profile and can be cost-effective. Inclusion of these dosage forms on drug formulary lists may help patients remain on therapy and reduce the economic and social burden of care.

Hypotension Due to Interaction Between Lisinopril and Tizanidine

OBJECTIVE

To report a case in which significant hypotension occurred after initiation of tizanidine in a patient using the antihypertensive agent lisinopril.

CASE SUMMARY

A 48-year-old woman was admitted due to cerebral hemorrhage at the midbrain and pons, with extension to the fourth ventricle. Consciousness disturbance (Glasgow coma scale 4) with a decerebrate posture improved 5 days after stroke onset. As the BP was fairly high, antihypertensive agents, including lisinopril, were initiated. Three weeks later, the decerebrate rigidity and high BP remained, and tizanidine was initiated to see whether the decrease in muscle tone could facilitate hypertension control and motor recovery. However, the BP dropped dramatically within 2 hours after the first dose of tizanidine. The tizanidine and all of the antihypertensive medications were withdrawn. Tizanidine was used again after her BP had stabilized, but did not produce similar problems.

DISCUSSION

A similar event was reported in 2000. The reaction in our patient appeared after tizanidine initiation and improved after both lisinopril and tizanidine were discontinued. According to the Naranjo probability scale, this was classified as a possible drug interaction. This kind of reaction is seldom mentioned as occurring during co-administration with tizanidine. With its characteristics, tizanidine has the potential to compromise hemodynamic stability during concomitant angiotensin-converting enzyme inhibitor use.

CONCLUSIONS

Based upon the literature review, the hypotension in this patient was possibly due to the interaction between tizanidine and lisinopril.

Facts and fiction of poor compliance as a cause of inadequate blood pressure control

OBJECTIVE

(i) To obtain an overview of measured compliance with antihypertensive medication; (ii) to explore sources of variation in measured compliance percentages between studies; and (iii) to investigate whether studies can establish a relationship between compliance and achieved blood pressure.

STUDY SELECTION

MEDLINE, PubMed and EMBASE databases were searched for studies, published between 1985 and 2003, in which patient compliance with antihypertensive medication was measured with electronic monitors.

DATA EXTRACTION

A standard form was used to extract relevant data from the included articles. Two investigators extracted all data independently.

RESULTS

Thirty studies were identified. The studies included were highly varied in their methods used to quantify compliance. Taking compliance and/or correct dosing were used in 20 studies. Mean taking compliance for a once-daily regimen was 94.0 +/- 4.4% and 88.2 +/- 6.5% for a twice-daily regimen. Mean correct dosing was 85.0 +/- 8.7% for a once-daily regimen and 75.3 +/- 6.5% for a twice-daily regimen. Proportions of patients with taking compliance or correct dosing </= 80% were provided by only five studies and ranged between 9 and 37%. Studies with a monitoring period exceeding 6 months showed a distinct decrease in compliance over time. Studies on the association between achieved blood pressure and compliance gave inconsistent results.

CONCLUSIONS

Although poor compliance is assumed to be an important explanation for inadequate blood pressure control, any convincing empirical evidence to support this hypothesis is currently lacking. The relationship between patient compliance and blood pressure control has not yet been properly established.

Strategy for the treatment of noncompliant hypertensive hemodialysis patients

Hypertensive hemodialysis patients noncompliant for their medications do not benefit from pharmacologic advances in the treatment of high blood pressure, and increase their already high risk of cardiovascular complications. The medical staff often becomes frustrated by severe hypertension in those who refuse to take medicines at home, drink excessive fluids, miss multiple dialysis sessions and sign-off dialysis early. In addition to addressing the psychosocial, financial, educational and substance abuse problems which contribute to noncompliance, we have developed a medication strategy to serve as an at least interim means of lowering blood pressure. Antihypertensive agents which have long half-lives in renal failure (lisinopril) and/or are intrinsically long acting (transdermal clonidine and amlodipine) were administered on dialysis days by the unit personnel to those patients who did not or would not take that or any dose on their own. The lisinopril and amlodipine were assured to have been taken on at least the dialysis days (thrice weekly), and the clonidine patch replaced weekly. Sixteen patients were thus treated when they failed to reliably self-administer medications. They had a significant decline in the predialysis systolic pressure of 15 mm Hg (175 +/- 6 to 160 +/- 5 mm Hg), diastolic of 12 mm Hg (103 +/- 3 to 91 +/- 3 mm Hg), and mean pressure of 13 mm Hg (127 +/- 4 to 114 +/- 4 mm Hg). There was an improvement in post-dialysis bood pressures, with the mean pressure declining 13 mm Hg from 110 +/- 4 to 97 +/- 4 mm Hg. Many individuals had erratic blood pressure control, having intermittently missed dialysis and hence unit-administered medicine, as well as continued fluid or drug abuse. The patients had uniformly excellent acceptance of this regimen, even spontaneously requesting it, and had no appreciable adverse effects. In summary while noncompliance is being addressed by the entire medical team, dialysis unit administration of long-acting medicines helps many hypertensive dialysis patients who would otherwise be at increased risk for severe cardiovascular complications.

Factors influencing erythropoietin compliance in peritoneal dialysis patients

BACKGROUND

Peritoneal dialysis patients who manage their own therapy with subcutaneous erythropoietin (EPO) may be at risk for noncompliance. The objectives of this study were to examine the rate of noncompliance and to investigate the factors that are associated with patient noncompliance with the prescribed EPO regimen.

METHODS

A multiple-choice questionnaire was mailed to eligible patients, and a review of pharmacy records was conducted for EPO dates of refill. Noncompliance was defined as less than 90% use of the prescribed dose either by pharmacy record review or missed injections on the questionnaire.

RESULTS

Of 55 eligible patients, 54 completed the questionnaire. The overall rate of noncompliance was 35%. Patients who were noncompliant were younger (P = 0.005), had fewer comorbidities (P = 0.050), had been on EPO therapy longer (P = 0.011), were more likely to have completed postsecondary education (P = 0.011), and were more likely to admit to missed peritoneal dialysis exchanges (P = 0.011). On multiple regression analysis, the independent predictors of noncompliance, in order of importance, were missing dialysis exchanges, completion of postsecondary education, and younger age.

CONCLUSION

These findings suggest that noncompliance with EPO injections is relatively common among peritoneal dialysis patients. The independent predictors of noncompliance were missing dialysis exchanges, completion of postsecondary education, and younger age. Further studies are needed to determine if specific interventions targeting this group of patients can affect compliance.

Transdermal clonidine skin reactions

The clonidine transdermal therapeutic system is being used as a therapy for blood pressure treatment. Systemic side effects seem to be fewer than with oral clonidine. However, localized skin reactions occur frequently and the incidence increases with the dose and duration of use. Common signs include erythema, scaling, vesiculation, excoriation, and induration. Allergic contact dermatitis is less frequent but common. Hyperpigmentation and depigmentation also occur. Pretreatment with 0.5% hydrocortisone is associated with less skin irritation and higher blood levels. Although oral clonidine is no longer widely used in the management of hypertension, awareness of these reactions to the transdermal delivery of this agent is important.

A systematic review of the associations between dose regimens and medication compliance

BACKGROUND

Previous reviews of the literature on medication compliance have confirmed the inverse relationship between number of daily doses and rate of compliance. However, compliance in most of these studies was based on patient self-report, blood-level monitoring, prescription refills, or pill count data, none of which are as accurate as electronic monitoring (EM).

OBJECTIVE

In this paper, we review studies in which compliance was measured with an EM device to determine the associations between dose frequency and medication compliance.

METHODS

Articles included in this review were identified through literature searches of MEDLINE, PsychInfo, HealthStar, Health & Psychosocial Instruments, and the Cochrane Library using the search terms patient compliance, patient adherence, electronic monitoring, and MEMS (medication event monitoring systems). The review was limited to studies reporting compliance measured by EM devices, the most accurate compliance assessment method to date. Because EM was introduced only in 1986, the literature search was restricted to the years 1986 to 2000. In the identified studies, data were pooled to calculate mean compliance with once-daily, twice-daily, 3-times-daily, and 4-times-daily dosing regimens. Because of heterogeneity in definitions of compliance, 2 major categories of compliance rates were defined: dose-taking (taking the prescribed number of pills each day) and dose-timing (taking pills within the prescribed time frame).

RESULTS

A total of 76 studies were identified. Mean dose-taking compliance was 71% +/- 17% (range, 34%-97%) and declined as the number of daily doses increased: 1 dose = 79% +/- 14%, 2 doses = 69% +/- 15%, 3 doses = 65% +/- 16%, 4 doses = 51% +/- 20% (P < 0.001 among dose schedules). Compliance was significantly higher for once-daily versus 3-times-daily (P = 0.008), once-daily versus 4-times-daily (P < 0.001), and twice-daily versus 4-times-daily regimens (P = 0.001); however, there were no significant differences in compliance between once-daily and twice-daily regimens or between twice-daily and 3-times-daily regimens. In the subset of 14 studies that reported dose-timing results, mean dose-timing compliance was 59% +/- 24%; more frequent dosing was associated with lower compliance rates.

CONCLUSIONS

A review of studies that measured compliance using EM confirmed that the prescribed number of doses per day is inversely related to compliance. Simpler, less frequent dosing regimens resulted in better compliance across a variety of therapeutic classes.

Medication compliance as a feature in drug development

Well-designed clinical trials maximize the information that can be obtained regarding the clinical pharmacology of a drug and, in turn, can streamline and enhance the drug development process. Until recently, little emphasis has been placed on integrating the role of variability in individual patterns of drug-taking into the drug development process. With the use of electronic monitoring, the temporal relationship between an individual's pattern of dosing and the prescribed regimen may be examined, and individual drug exposure may be estimated based on the actual history of dosing. As a result, accurate estimation of exposure-response relationships (or surrogate markers of response) can be obtained. Considerations in the design of clinical trials must therefore be expanded to include appropriate methods to measure compliance, sufficient frequency of monitoring to allow the time course of response to be mapped, and the use of statistically valid methods of data analysis.

Taking antihypertensive medication--controlling or co-operating with patients?

Low compliance with antihypertensive drug regimens has been a well documented reason for inadequate control of hypertension. We assessed recent literature regarding compliance from different disciplines to clarify the nature of reported problems on low compliance to prescribed antihypertensive medication. Much research focuses on primary factors for compliance, methods to monitor and measure individual rates and patterns of compliance. From a behavioural oriented point of view, the focus is on understanding why patients act as they do. This review indicates that there is an almost complete lack of knowledge about how the decision making in the clinical practice is organized when prescribing antihypertensive medication and/or when following up treatment from patients already taking such drugs. Since the concrete communication and collaboration between patient and physician in the clinical setting are of prime significance for patient adherence to drug regimens, it is important to shed light on what happens in this critical situation.

The USA experience with the clonidine transdermal therapeutic system

Cardiovascular diseases are the leading causes of death in the United States, with hypertension being amongst the most prevalent of the cardiovascular risk factors. Improvement of hypertension management has, in consequence, received much attention. Extensive pre- and post-marketing experience with the transdermal formulation of clonidine marketed in the USA in the mid-1980s has now been accumulated. Transdermal clonidine is effective as monotherapy in mild-moderate hypertension, and in combination with diuretics, calcium antagonists and ACE inhibitors in more resistant cases. It controls blood pressure throughout the 24-h circadian cycle. It is effective and generally well-tolerated in adolescents, the elderly, blacks, diabetics, and subjects with chronic renal insufficiency. It has been used perioperatively and for suppression of adrenergic symptoms in subjects withdrawing from addicting substances. In comparison with oral clonidine, transdermal clonidine reduces the incidence and severity of such symptomatic side-effects as dry mouth, drowsiness, and sexual dysfunction. Minor skin reactions occur at the site of application of the transdermal patch with moderate frequency. Adherence to transdermal clonidine therapy is high, and patients commonly prefer it to oral therapy. Transdermal administration of clonidine is a useful therapeutic advance in the long-term management of hypertension.

Long-term (5 year) experience with transdermal clonidine in the treatment of mild to moderate hypertension

The long-term safety and efficacy of transdermal clonidine (C-TTS) was evaluated in 102 patients with mild to moderate hypertension over a mean treatment period of 4.9 +/- 1.4 years. C-TTS size 1 was used by 29.4%, C-TTS size 2 by 35.3%; in 35.3% of the patients a diuretic agent was given in addition. The baseline blood pressure of 168/100 mmHg was reduced to 150/85 mmHg at the end of titration and remained stable during long-term treatment. After 5 years seated blood pressure was 147/83 mmHg. Systemic side-effects, e.g. 4.9% dry mouth, were reported mainly during the first month. Transient local side-effects occurred mainly between weeks 4-26, thereafter the incidence clearly diminished and did not cause any withdrawal due to skin reactions from 1 year up to 6.5 years. Overall the long-term transdermal clonidine treatment was highly accepted by the patients, was effective and was well tolerated.

Transdermal clonidine as an adjunct to nifedipine-GITS therapy in patients with mild-to-moderate hypertension

Calcium channel blockers and central alpha-agonists are among the classes of antihypertensive drugs that yield the most favorable overall effects on risk factors for hypertension-related end-organ damage. An open-label prospective trial in 42 patients with a mean baseline blood pressure of 144/102 mm Hg sought to assess the usefulness of adjunctive treatment with transdermal clonidine (0.1 to 0.3 mg/day) in patients responding inadequately to nifedipine--gastrointestinal therapeutic system (GITS) (30 to 60 mg/day) monotherapy. Thirty-nine patients who failed to reach the goal of a seated mean diastolic blood pressure of < 90 mm Hg when treated only with once-a-day nifedipine-GITS entered a transdermal clonidine (once a week) titration phase followed by an 8-week maintenance course of the two drugs combined. The 35 patients completing this last phase responded with a mean seated diastolic blood pressure of 127/87 mm Hg. Only six patients required the highest dose of clonidine for control. A 97% compliance rate with the transdermal medication contrasted with a compliance rate of only 73% for the oral nifedipine. Two of three patients who had contact dermatitis after wearing a transdermal clonidine patch withdrew from the trial prematurely; other minor side effects required no interruption of therapy. The nifedipine-clonidine combination not only achieved blood pressure control in these patients but may prove advantageous in combining the protective effects of the two agents against complications of the hypertensive syndrome.