β-Blockers - Like leaving the light on all night

Beta Blockers diminish the effects of EPINEPHRINE (ADRENALINE) and other stress hormones.  By blocking their action on ß-adrenergic receptors.

People who take beta blockers (at least in the evening) are setting the stage for insomnia, depression and other mental disturbances - due to the interdependence of the SAMe methyl donor and hormones SEROTONIN and MELATONIN.

SAMe -And Other Methyl Donor Molecules

MELATONIN synthesis depends on the stimulation of pineal ß-adrenergic receptors by NOREPINEPHRINE (NE).   This normally occurs as the sun goes down. NE-stimulation of ß-adrenergic receptors causes the release of Serotonin-N-Acetyltransferase (NAT), a crucial enzyme for MELATONIN synthesis.

ß-blockers are a class of drugs used to treat heart problems by blocking ß-receptors in the heart (E.g. Inderal, Tenormin, Lopressor (Toprol)).   The problem is that they also block brain receptors and blocking pineal adrenergic receptors interferes with the synthesis of MELATONIN.

Two studies that demonstrate the disruption to circadian rhythms (and hormones dependent on these rhythms) by taking ß-blockers

-   An animal study showed the disruption to circadian rhythms (and hormones dependent on these rhythms) by taking a ß-blocker before bedtime.   Effects are akin to leaving the lights on all night and closely resemble sleep deprivation:

•   SEROTONIN remains unnaturally high - which normally drop at night;

•   SAMe doesn't decrease - which it should

•   MELATONIN doesn't increase

-   In a human study, MELATONIN levels fell significantly in hypertensive patients taking ß-blocker compared to controls, and wakefulness increased.   Researchers gave hypertensive patients one of three beta-blockers: propranolol (Inderal), atenolol (Tenormin), or metoprolol (Lopressor or Toprol XL).

MELATONIN levels were measured against those of a control group. Metoprolol decreased MELATONIN more than atenolol or propranolol. The three patients with the lowest levels of MELATONIN reported nightmares. With chronic use of beta-blockers MELATONIN continues to be suppressed.

Brismar K, Hylander B, Elilasson K, Rossner S and Wetterberg L. 1988. Melatonin secretion related to side-effects of beta-blockers from the central nervous system. Acta Med Scand 223: 525-30.

-   ß-blockers suppress SEROTONIN as well as MELATONIN.   Thus, it is not surprising that the Physicians Desk Reference lists mental depression, fatigue, short-term memory loss, insomnia and emotional problems as some of the side effects of Inderal and other ß- blockers. Apparently unaware of the role ß- receptors play in getting a good night's sleep, the manufacturer of Inderal, Wyeth-Ayerst, recommends that these drugs be taken at bedtime.