Introduction

Beta-blockers function by reducing certain cellular activity, which helps regulate heart rate, blood pressure, and other parameters. The most prevalent conditions treated with beta-blockers are those in the heart and circulatory system. Additionally, they are occasionally utilised to treat disorders of the neurological system and brain.¹ Beta-blockers are indicated and have Food and Drug Administration (FDA) approval for the treatment of tachycardia, hypertension, myocardial infarction, congestive heart failure, cardiac arrhythmias, coronary artery disease, hyperthyroidism, essential tremor, aortic dissection, portal hypertension, glaucoma, migraine prophylaxis, and other conditions. Less common ailments including hypertrophic obstructive cardiomyopathy and long QT syndrome are also treated with them.² One of the most prevalent side effects of beta blockers is insomnia. Beta-blockers have been demonstrated to suppress melatonin generation via specific inhibition of adrenergic beta-1 receptors.³

Mechanisms of beta-blockers  

The activation of B1 receptors causes the catecholamines (norepinephrine and epinephrine) and cardiac automaticity to increase along with conduction velocity. Additionally, B1 receptors induce the release of renin, which raises blood pressure. On the other hand, binding to B2 receptors results in increased metabolic consequences such as glycogenolysis and smooth muscle relaxation.

Beta-blockers suppress these effects after binding to the B1 and B2 receptors. As a result, the heart's chronotropic and inotropic actions are inhibited, which causes the heart rate to decrease. Additionally, beta-blockers lower blood pressure through several methods, such as decreased cardiac output and renin. The reduction in oxygen demand caused by the adverse chronotropic and inotropic effects is how beta-blocker use improves angina. These drugs have a strong antiarrhythmic impact and lengthen the atrial refractory periods.²

Sleep disturbance as a side effect

Overview of reported sleep-related issues

Because beta-blockers reduce melatonin release, some patients may have insomnia and altered sleep patterns. Lipophilic beta-blockers have been connected with a multitude of sleep disorders, including insomnia, hypnogogic hallucinations, sleepwalking, and nightmares.⁴ For a considerable amount of time, beta-blockers have been linked to sleep disorders including insomnia and trouble getting or staying asleep. It has been demonstrated that they decrease melatonin synthesis by selectively inhibiting beta-1 adrenergic receptors. The pineal gland in the brain secretes the hormone melatonin, which aids in preserving regular circadian cycles.⁵

Potential reasons for sleep disturbance

1. Insomnia – beta blockers can interfere with the sleep-wake cycle in some individuals, leading to difficulty falling asleep or staying asleep
2. Vivid dreams or nightmares – some people may experience more vivid dreams or nightmares while taking beta blockers, which can disrupt sleep
3. Fatigue – while fatigue is a common side effect of beta-blockers, paradoxically, some individuals may also experience difficulty sleeping or disrupted sleep patterns
4. Lowered melatonin production – beta-blockers may reduce the production of melatonin, a hormone that regulates sleep-wake cycles, potentially affecting sleep quality
5. Increased anxiety or depression – in some cases, beta-blockers may contribute to feelings of anxiety or depression, which can, in turn, impact sleep
6. Bradyarrhythmias –beta blockers can slow the heart rate (bradycardia). In some cases, this may result in a sensation of palpitations or irregular heartbeats, which can disturb sleep
7. Nocturia–beta blockers can affect kidney function, potentially leading to increased urine production and nocturia (waking up during the night to urinate), which can disrupt sleep
8. Individual sensitivity – individual responses to medications vary. Some people may be more sensitive to the effects of beta-blockers on sleep than others⁶

Patient experiences

A male patient, age 49, who had a medical history of hypertension and obstructive sleep apnea, reported experiencing parasomnia six days a week. The sleep behaviour occurs within 1 hour of sleep and includes sleepwalking and grasping his wife’s arm.

He denied recalling vivid dreams or insomnia. The patient underwent polysomnography, which did not reveal rapid eye movement (REM) without atonia. Repeated polysomnography with continuous positive airway pressure again didn't reveal REM without atonia or unusual sleep behaviour. He had a trial of clonazepam without benefit.

Post-traumatic stress disorder, anxiety, depression, alcoholism, and family history were all ruled out as additional causes of insomnia. For more than ten years, the patient received high-dose metoprolol tartrate treatment for hypertension. With the guidance of a cardiologist, he stopped metoprolol with a resolution of his non-REM parasomnia. Beta-blockers are a popular class of medications used to treat hypertension, heart failure, and arrhythmias.

Despite their proven benefit, they have also been associated with sleep disorders and unwanted sleep behaviours. There have been 13 documented cases so far that link beta-blocker medication to sleep disturbances. In this case, the patient had no psychiatric history or reported REM or non-REM parasomnias. Reviewing his medical records revealed that the start of his beta-blocker medication was accompanied by his non-REM sleep habits.

Additionally, his symptoms resolved shortly after discontinuing his metoprolol. It is possible to understand how beta-blockers cause sleep disturbances and parasomnias by considering the correlation between the likelihood of 5-hydroxytryptamine (5-HT) receptor occupancy and cause sleep disorders in beta-blocking agents based on analysis of the beta-1, beta-2, and 5-HT receptor occupancies for different beta-blocking agents.

The lipophilic nature of the beta-blocker agent metoprolol was attributed as a potentiating agent for CNS side effects. A growing body of research indicates that beta-adrenergic inhibiting medications may be linked to severe insomnia. Dose reduction or discontinuation of these agents should be considered by clinicians in a setting of unexplained causes of non-REM parasomnias.⁷

Managing beta blocker-related sleep disturbance  

Most concerningly, poor sleep quality is a serious health issue in and of itself, and insomnia has been connected to a variety of conditions, from cancer to depression. Therefore, for people taking beta-blocker medication, melatonin administration and CoQ10 supplements are good options.⁶

Tips for individuals taking beta blockers

In addition to being injected intramuscularly, beta-blockers can be obtained orally, intravenously, or for ocular use. Different ranges of dosages are offered based on the particular drug. Outpatient prescriptions may include once-a-day doses for longer-acting beta-blockers, such as metoprolol succinate. On the other hand, most beta blockers require at least two daily doses. Depending on the indication and dosage, certain beta-blockers, such as propranolol, which has a half-life of roughly 4 hours, can be dosed up to 3 or 4 times per day.² 

Lifestyle modifications to improve sleep

• Maintain consistency
• Ensure that your bedroom is calm, dark, cosy, and the ideal temperature
• Take out all electronics from the bedroom, including computers, TVs, and smartphones
• Get moving – engaging in physical activity throughout the day can facilitate easier nighttime sleep⁸

Summary

The relationship between beta blockers and sleep disturbance is a complex and multifaceted one. While beta-blockers are commonly prescribed to manage various cardiovascular conditions, they may have unintended effects on sleep patterns for some individuals. The mechanisms through which beta blockers influence sleep are not fully understood, and the impact on sleep quality can vary among users.

Research suggests that beta-blockers may contribute to sleep disturbances by affecting factors such as melatonin production, adrenergic signalling, and overall sleep architecture. However, individual responses to beta-blockers differ, and not everyone taking these medications will experience sleep-related side effects.

Healthcare professionals should be vigilant in monitoring patients on beta blockers for any signs of sleep disruption and consider alternative medications or dosage adjustments if sleep disturbances become problematic. Patients, in turn, should communicate openly with their healthcare providers about any sleep-related issues they may be experiencing while on beta blockers.

In summary, while beta blockers play a crucial role in managing cardiovascular conditions, their potential impact on sleep underscores the importance of personalized and attentive medical care. Further research is needed to better understand the specific mechanisms involved and to develop strategies to mitigate sleep disturbances associated with beta-blocker use.