Carvedilol therapy after cocaine-induced myocardial infarction in patients with asthma

Respiratory effect of beta-blockers in people with asthma and cardiovascular disease: population-based nested case control study

BACKGROUND

Cardiovascular disease (CVD) is a common comorbidity in people with asthma. However, safety concerns have caused heterogeneity in clinical guideline recommendations over the use of cardioselective beta-blockers in people with asthma and CVD, partly because risk in the general population has been poorly quantified. The aim of this study was to measure the risk of asthma exacerbations with beta-blockers prescribed to a general population with asthma and CVD.

METHODS

Linked data from the UK Clinical Practice Research Datalink was used to perform nested case-control studies among people with asthma and CVD matched on age, sex and calendar time. Adjusted incidence rate ratios (IRR) were calculated for the association between oral beta-blocker use and moderate asthma exacerbations (rescue oral steroids) or severe asthma exacerbations (hospitalisation or death) using conditional logistic regression.

RESULTS

The cohort consisted of 35,502 people identified with active asthma and CVD, of which 14.1% and 1.2% were prescribed cardioselective and non-selective beta-blockers, respectively, during follow-up. Cardioselective beta-blocker use was not associated with a significantly increased risk of moderate or severe asthma exacerbations. Consistent results were obtained following sensitivity analyses and a self-controlled case series approach. In contrast, non-selective beta-blockers were associated with a significantly increased risk of moderate asthma exacerbations when initiated at low to moderate doses (IRR 5.16, 95% CI 1.83-14.54, P = 0.002), and both moderate and severe exacerbations when prescribed chronically at high dose (IRR 2.68, 95% CI 1.08-6.64, P = 0.033 and IRR 12.11, 95% CI 1.02-144.11, P = 0.048, respectively).

CONCLUSIONS

Cardioselective beta-blockers prescribed to people with asthma and CVD were not associated with a significantly increased risk of moderate or severe asthma exacerbations and potentially could be used more widely when strongly indicated.

Carvedilol does not reduce cocaine use in methadone-maintained cocaine users

INTRODUCTION

The goal of this study was too test the efficacy of carvedilol (CAR), an adrenergic blocker, for reducing cocaine use in individuals with cocaine use disorder (CUD). We conducted a 17-week, double-blind, randomized controlled trial with 3 treatment arms: 25mg CAR, 50mg CAR, and placebo.

METHODS

One hundred and six treatment-seeking opioid and cocaine-dependent participants, who were also maintained on methadone during study participation, were randomized to placebo (n=34), 25mg/day CAR (n=37) or 50mg/day CAR (n=35). The main outcome measures were cocaine and opioid use as assessed by urine drug screening and self-reported drug use.

RESULTS

No significant group differences were found for treatment retention with 56% of the placebo, 76% of the 25mg and 66% of the 50mg CAR groups (p>0.05) completing treatment. The percentage (SD) of cocaine positive urines during the trial showed an overall treatment effect: 59.2 (38.9) for the placebo, 50.8 (33.8) for the 25mg and 75.1 (33.2) for the 50mg CAR group. In post hoc comparisons, neither the 25 nor 50mg CAR condition differed significantly from the placebo; however, the 25mg CAR group had a significantly lower proportion of cocaine-positive urines than the 50mg group. No significant group differences were found for the percentage of self-reported days of cocaine abstinence during the trial: 72.9 (25.3) for placebo, 72.9 (29) for CAR 25mg, and 59.3 (31.7) for CAR 50mg. Significant groups differences in the proportion of opioid positive urines submitted were not observed (p>0.05). Baseline cocaine withdrawal severity did not predict treatment response (p>0.05).

CONCLUSIONS

These findings did not support the efficacy of CAR for the treatment of cocaine use in cocaine and opioid dependent participants maintained on methadone. Further, CAR doses >25mg should not be used to avoid possible increases in cocaine and opioid use.

Early use of beta blockers in patients with cocaine associated chest pain

BACKGROUND

The most common symptom of cocaine abuse is chest pain. Cocaine induced chest pain (CICP) shares patho-physiological pathways with the acute coronary syndromes (ACS). A key event is the increase of activity of the adrenergic system. Beta blockers (BBs), a cornerstone in the treatment of ACS, are felt to be contraindicated in the patient with CICP due to a potential of an "unopposed alpha adrenergic effect (UAE)".

OBJECTIVES

Identify signs of UAE and in-hospital complications in patients who received BB while having cocaine induced chest pain.

METHODS

We performed a retrospective review of 378 patients admitted to a medical unit because of CICP. Twenty six of these were given a BB at the time of admission while having CICP. We compared these patients to a control group paired by age, sex, race and history of hypertension who did not received a BB while having CICP. Blood pressure, heart rate, length of stay and in-hospital cardiovascular complications were compared.

RESULTS

No statistically significant differences were found between the two groups except for a longer length of stay in the case group. This was felt to be due to unrelated causes.

CONCLUSIONS

This study does not support the presence of an UAE in patients with continuing CICP and treated early with BB. There were no in-hospital cardiovascular complications in the group of patients who had an early dose of BB while having CICP.

IMPLICATIONS

BB appeared safe when given early on admission to patients with CICP.

Drugs currently in Phase II clinical trials for cocaine addiction

INTRODUCTION

There are no FDA-approved pharmacotherapies for treating cocaine addiction; thus, developing drugs to treat cocaine dependence is an unmet critical need. Fortunately, there are a number of drugs that are currently in Phase II clinical trial/s. This is due in part to the advances from in vivo imaging in humans which provided a roadmap of the neurochemistry of the cocaine-dependent brain. Most drugs currently in Phase II clinical trials attempt to modulate the disturbed neurochemistry in cocaine dependents to resemble those of healthy individuals. These predominantly modulate dopamine, serotonin, glutamate, GABA or noradrenaline signalling.

AREAS COVERED

This review summarizes the therapeutic potential of each drug as evidenced by clinical and preclinical studies. It also discusses their utility in terms of bioavailability and half-life.

EXPERT OPINION

Amphetamine salts and topiramate clearly stand out in terms of their potential efficacy in treating cocaine addiction. The efficacy of topiramate was closely associated with regular cognitive-behavioural therapy (CBT), which highlights the importance of a combined effort to promote abstinence and enhance retention via CBT. Cognitive/psychological screening appears necessary for a more symptom-based approach with more reasonable outcomes other than abstinence (e.g., improved quality of life) in treating cocaine addiction.

Risk of emergent bradycardia associated with the use of carvedilol and metoprolol in routine clinical practice

BACKGROUND

Large randomized trials have reported mixed results regarding the risk of bradycardia between metoprolol and carvedilol. We compared the incidence of emergent bradycardia (measured by an emergency department visit or hospitalization due to bradycardia) for patients initiating metoprolol and carvedilol.

METHODS

Adult beneficiaries of Medi-Cal, the State of California Medicaid program, without a diagnosis of bradycardia who initiated metoprolol or carvedilol between May 1, 2004, and November 1, 2009, were included. Cox proportional hazard regression analysis was performed to model the time to first occurrence of emergent bradycardia after initiation of the study drugs as a dependent variable and the study drug (metoprolol vs carvedilol) as the primary predictor with adjustments for total daily metoprolol-equivalent dose, formulations, and use of nonstudy drugs as time-varying covariates, as well as demographics and comorbidities.

RESULTS

Among 38,186 subjects, 77.7% initiated metoprolol and 22.3% initiated carvedilol. The incidence of emergent bradycardia was low and comparable between the drugs (18.1 per 1000 person-years using metoprolol vs 17.7 per 100 person-years using carvedilol; unadjusted hazard ratio, 1.07; 95% confidence interval, 0.76-1.49). However, carvedilol users had substantially different population characteristics compared with metoprolol users. After adjustments for demographics, comorbidities, metoprolol-equivalent dose, formulations, and use of nonstudy drugs, initiation of metoprolol was associated with an increased risk of emergent bradycardia compared with that of carvedilol (adjusted hazard ratio, 1.64; 95% confidence interval, 1.14-2.36).

CONCLUSIONS

Initiation of metoprolol is associated with an increased risk of emergent bradycardia compared with carvedilol, although the overall incidence of emergent bradycardia is low in routine clinical practice.

Cardioselective beta-blocker treatment of hypertension in patients with asthma: when do benefits outweigh risks?

BACKGROUND

Benefits outweigh risks of cardioselective beta-blocker therapy in patients with nonsevere asthma and a history of heart failure or myocardial infarction (MI). This review summarizes the risks versus benefits of using cardioselective beta-blockers in the treatment of hypertension in patients with asthma.

METHODS

We searched the English literature from 1976 to 2011 via PubMed, EMBASE, and SCOPUS using the following search terms: "beta-blocker treatment of hypertension" AND "asthma"; "cardioselective beta-blockers" AND "asthma." When pertinent articles were found, we assessed relevant articles cited in those papers. All studies related to cardioselective beta-blocker use in patients with asthma and hypertension were included.

RESULTS

Seven studies with patient populations ranging from 10 to 17 patients evaluated cardioselective beta-blockers in patients with asthma and hypertension. Atenolol and/or immediate-release metoprolol were evaluated in these studies. The duration of beta-blocker therapy in four studies was 1-8 weeks; two studies were single dose and one investigation lasted 8 months. Metoprolol and atenolol were generally well tolerated except at higher doses such as metoprolol >100 mg daily.

CONCLUSION

In the absence of concomitant cardiovascular disease, routine use of beta-blockers for the treatment of hypertension in patients with asthma should be avoided.