• competitively blocks the effects of norepinephrine
• have equal affinity for binding to beta1 and beta2 receptors
• do NOT have ISA (intrinsic sympathomimetic activity)
• decrease heart rate
• reduce the force of cardiac contraction
• blocks the release of renin
• peripheral resistance increases initially as a result of blocking beta2 receptors on blood vessels
• long-term use of beta-blockers decrease peripheral resistance

1. heart failure - if there is pre-existing poor left ventricular function
2. excessive bradycardia
3. bronchospasm in asthamatics
4. hypoglycemic episodes in diabetics by blocking gluconeogenesis in the liver (beta2 receptor mediated action)
5. increase the plasma concentration of triglycerides
6. CNS effects: sleep disturbance, vivid dreams, hallucinations
7. sudden withdrawal syndrome
8. additive effects when verapamil or diltiazem is co-administered

• nadolol is a long-acting antagonist
• nadolol does not enter the CNS as well as propranolol
• the ocular formation of timolol is used to treat glaucoma

• have greater afffinity for beta1 receptors than beta2
• cardioselective beta blockers
• produce less bronchoconstriction and other beta2 receptor mediated effects
• their selectivity for beta1 receptors is not absolute
• low or no ISA
• decrease HR
• reduce force of cardiac contraction 
• blocks the release of renin

1. withdrawal symptoms with abrupt discontinuation
2. AV block
3. bradycardia
4. pulmonary edema

• metoprolol is more lipid soluble than atenolol, but less than propranolol and betaxolol
• betaxolol is available as an opthalamic preparation for glaucoma
• betaxolol is less likely to induce bronchospasm than non-selective beta blocker, timolol

1. hypertension (all)
2. angina (all)
3. heart failure (all)
4. migraine prophylaxis (metoprolol, atenolol)
5. tremor (metoprolol)
6. glaucoma (betaxolol)

• pindolol is an oral non-selective beta blocker with ISA
• the partial agonist potential of pindolol is greater for beta2 than for beta1
• the negative chronotropic and inotropic properties of pindolol are attenuated by the drug's ISA effects
• acebutolol is an oral cardioselective beta-blocker with mild ISA
• as a result of ISA, acebutolol is less likely than other beta blockers to cause bradycardia and cold extremities
• penbutolol is a non-selective beta blocker with ISA
• penbutolol has high lipid solubility

• beta blockers with slight partial agonist activity may produce smaller reductions in resting heart rate and blood pressure
• these drugs are preferred as antihypertensive agents in individuals with diminished cardiac reserve or a propensity for bradycardia

• labetolol is a non-selective beta blocker with partial agonist activity and a selective alpha1 blocker
• labetolol decreases heart rate and cardiac output as  a result of beta1 receptor blockade and it decreases peripheral vascular resistance as a result of alpha1 receptor blockade
• carvedilol is a non-selective beta blocker and a selective alpha1 blocker (1:10 = alpha1:beta)
• carvedilol also has antioxidant and antiproliferative effects (beneficial for CHF patients)

labetolol has two optical centers and there are four diastereoisomers

the beta-blocking activity of labetolol or carvedilol is much greater than the alpha-blocking activity

carvedilol exerts other cardioprotective effects that make it useful in treatment of myocardial infarction and heart failure

• beta1 selective at 5mg doses but loses selectivity at >10mg
• contains a NO potentiating effect
• less beta blocker related side effects such as fatigue, bradycardia, and impotence
• binds to beta3 and causes the release of NO from endothelial cells

Non-Selective Beta Blocker

Indication:

glaucoma

Non-Selective Beta Blocker

Nadolol is a long acting antagonist

It does not enter the CNS as well as Propranolol

Selective Beta1 Antagonist

More lipid soluble than atenolol but less lipid soluble than propranolol

Indications:

1. hypertension
2. angina
3. heart failure
4. migraine prophylaxis
5. tremor

Selective Beta1 Antagonist

Indications:

1. hypertension
2. angina
3. heart failure
4. migraine prophylaxis

Selective Beta1 Antagonist

Indications:

1. hypertension
2. angina
3. heart failure

Selective Beta1 Antagonist

Less likely to induce bronchospasms than non-selective beta blocker timolol

Indications:

1. hypertension
2. angina
3. heart failure
4. glaucoma

Beta Blocker with ISA

• An oral cardioselective beta blocker with mild ISA
• As a result of ISA, it is less likely than other beta blockers to cause bradycardia and cold extremities 

Beta Blocker with ISA

• The partial agonist potential is greater for beta2 than beta1
• the negative chronotropic and inotropic properties are attenuated by the drug's ISA effect

Combined Alpha1 and Non-Selective Beta Blocker

• Blocking ratio is 1:10 alpha1 to beta
• Carvedilol also has antioxidant and antiproliferative effects (beneficial for CHF patients)

Combined Alph1 and Non-Selective Beta Blocker

Has partial agonist activity at beta2 receptor

Decreases HR and CO as a result of beta1 blockade and decreases peripheral vascular resistance as a result of alpha1 blockade