beta-blockers

Examples of beta-blockers in the following topics:

• Agonists, Antagonists, and Drugs

  • Beta blockers (sometimes written as β-blockers) or beta-adrenergic blocking agents, beta-adrenergic antagonists, beta-adrenoreceptor antagonists, or beta antagonists, are a class of drugs used for various indications.
  • As beta-adrenergic receptor antagonists, they diminish the effects of epinephrine (adrenaline) and other stress hormones.
  • Beta blockers block the action of endogenous catecholamines—epinephrine (adrenaline) and norepinephrine (noradrenaline) in particular—on β-adrenergic receptors, part of the sympathetic nervous system that mediates the fight-or-flight response.

• Signs and Symptoms of Shock

  • While a fast heart rate is common, those on beta blockers and those who are athletic may have a normal or slow heart rate.

• Raynaud's Phenomenon

  • Drugs which may cause secondary Raynaud's include beta-blockers, chemotherapeutics, and anthrax vaccines.
  • Raynaud's can also be treated with medications that prevent vasoconstriction, such as calcium channel blockers.

• Asthma

  • Treatment of acute symptoms is usually with an inhaled short-acting beta-2 agonist (such as salbutamol).
  • The most common triggers include allergens, smoke (tobacco and other), air pollution, non selective beta-blockers, and sulfite-containing foods.

• Social Anxiety Disorder (Social Phobia)

  • Other commonly used medications include beta blockers and benzodiazepines.

• Thyroid Gland Disorders

  • In the case of Graves' disease, beta blockers are used to decrease symptoms of hyperthyroidism and anti-thyroid drugs are used to decrease the production of thyroid hormones.

• Marfan Syndrome

  • Beta blockers have been used to control arrhythmias and slow the heart rate.

• Beta Decay

  • Beta decay is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted from an atomic nucleus.
  • There are two types of beta decay.
  • Beta minus (β) leads to an electron emission (e−); beta plus (β+) leads to a positron emission (e+).
  • Beta decay is mediated by the weak force.
  • The continuous energy spectra of beta particles occur because Q is shared between a beta particle and a neutrino.

• The Fields

  • $\displaystyle \beta \equiv \frac{\bf u}{c},~\text{so}~ \kappa = 1 - {\bf n} \cdot \beta$
  • $\displaystyle {\bf E}(r,t) = \kern-2mm q \left [ \frac{({\bf n} - \beta)(1-\beta^2)}{\kappa^3 R^2} \right ]_\mathrm{ret}\!
  • \frac{q}{c} \left [ \frac{\bf n}{\kappa^3 R} \times \left [ ({\bf n} - \beta ) \times \dot{\beta} \right ]\right ]_\mathrm{ret} \\ {\bf B}(r,t) = \kern-2mm\left [ {\bf n} \times {\bf E}(r,t) \right ]_\mathrm{ret}.$
  • $\displaystyle {\bf E}_{rad}(r,t) = + \frac{q}{c} \left [ \frac{\bf n}{\kappa^3 R} \times \left [ ({\bf n} - \beta ) \times \dot{\beta} \right ]\right ] \\ {\bf B}_{rad}(r,t) = \left [ {\bf n} \times {\bf E}_{rad}(r,t) \right ].$
  • $\displaystyle {\bf S} = {\bf n} \frac{q^2}{4\pi c \kappa^6 R^2} \left | {\bf n} \times \left \{ \left ( {\bf n} - \beta \right ) \times {\dot{\beta}} \right \} \right |^2$

• Angle Addition and Subtraction Formulae

  • $\begin{aligned} \cos(\alpha + \beta) &= \cos \alpha \cos \beta - \sin \alpha \sin \beta \\ \cos(\alpha - \beta) &= \cos \alpha \cos \beta + \sin \alpha \sin \beta \end{aligned}$
  • $\begin{aligned} \sin(\alpha + \beta) &= \sin \alpha \cos \beta + \cos \alpha \sin \beta \\ \sin(\alpha - \beta) &= \sin \alpha \cos \beta - \cos \alpha \sin \beta \end{aligned}$
  • $\displaystyle{ \begin{aligned} \tan(\alpha + \beta) &= \frac{ \tan \alpha + \tan \beta}{1 - \tan \alpha \tan \beta} \\ \tan(\alpha - \beta) &= \frac{ \tan \alpha - \tan \beta}{1 + \tan \alpha \tan \beta} \end{aligned} }$
  • Apply the formula $\cos(\alpha - \beta) = \cos \alpha \cos \beta + \sin \alpha \sin \beta$:
  • We can thus apply the formula for sine of the difference of two angles: $\sin(\alpha - \beta) = \sin \alpha \cos \beta - \cos \alpha \sin \beta$.