Medicine & USMLE

Side Effects of Beta Blockers

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Alpha & Beta Blockers (New)
  1. Phentolamine
  2. Phenoxybenzamine
  3. -osin Drugs
  4. Beta-1 Selective Beta Blockers
  5. Non-Selective Beta Blockers
  6. Dual Alpha Beta Blockers
  7. Nebivolol
  8. Clinical Use of Beta Blockers
  9. Side Effects of Beta Blockers

Summary

The major side effects of beta blockers include weight gain, cardiovascular depression, sleep disturbances like insomnia and nightmares, unopposed alpha agonism, bronchoconstriction, and erectile dysfunction. Beta blockers may also mask the signs of hypoglycemia. The beta blocker metoprolol specifically can also cause hyperlipidemia.

Key Points

  • Side Effects of Beta Blockers
    • Erectile dysfunction
      • While this side effect is commonly reported, clinical evidence suggests that this is a relatively rare side effect (<1% increase) and less severe than previously thought
    • Cardiovascular depression (bradycardia, AV block, HF)
      • While beta-blockers are helpful for preventing chronic remodeling and reducing mortality, they may reduce heart function and exacerbate acute decompensated heart failure
      • Sinus bradycardia is an expected and normal response to beta blockers
    • CNS effects (seizures, sleep alterations)
      • This is controversial; even highly lipophilic beta-blockers have not been shown to greatly increase risk of CNS side effects
      • CNS effects may include depression, fatigue, sedation, insomnia, and nightmares, but seizures are not a common side effect of taking beta blockers
    • Dyslipidemia (metoprolol)
      • Traditional beta blockers (such as atenolol, metoprolol, and propranolol) have been shown to increase triglycerides, and decrease HDL cholesterol (little to no effect on LDL cholesterol); This effect is not seen with combined alpha-beta blockers (like carvedilol or labetalol) or those with partial agonist activity (like acebutolol or pindolol)
    • Masks hypoglycemia
      • Beta-blockers may inhibit the outward signs of hypoglycemia (tachycardia, anxiety)
    • Asthma/COPD exacerbations
      • Due to inhibition of beta-2 receptor-mediated bronchodilation
      • Beta blockers should be avoided in patients with asthma or reactive airway disease; this is not a strict contraindication
    • Unopposed α-adrenergic stimulation
      • This is relevant for the treatment of cocaine toxicity or pheochromocytoma
      • Beta-blockers should never be used first for treating these patients and should usually be combined with an alpha-blocker
    • Weight Gain
      • Mostly occurs in the first few months after starting a beta-blocker