chap 8

• Propranolol


  Non-selective beta blocker that can bind to both beta 1 and beta 2 receptors
• Carvedilol


  Mixed acting beta blocker with alpha receptor antagonist activity
• Pindolol


  Beta blocker with partial agonist activity
• Metoprolol


  Cardioselective beta blocker that primarily binds to beta 1 receptors
• Adverse effect of alpha 1 antagonists
• Mechanism of action of phentolamine

  Binds to and blocks alpha 1 and alpha 2 receptors, preventing binding of epinephrine and norepinephrine
• Tamsulosin


  Alpha 1 receptor selective antagonist
• Carvedilol


  Mixed acting beta blocker that binds to both alpha and beta receptors
• Prazosin


  Alpha 1 receptor selective antagonist
• Yohimbine


  Alpha 2 receptor selective antagonist
• Synaptic potential


  Excitatory (EPSP) or inhibitory (IPSP) changes in the postsynaptic membrane potential caused by neurotransmitter release
• Excitatory neurotransmitters
• Inhibitory neurotransmitters
• Excitatory pathway
• Inhibitory pathway
• Neurodegenerative diseases
• Parkinson's disease


  Progressive neurological disorder involving motor symptoms like tremors, rigidity, bradykinesia, and gait abnormalities
• Cause of Parkinson's disease
• Parkinsonism


  The person does not really have a real Parkinson's disease, pseudo means false
• Pseudo-parkinsonism


  Signs and symptoms of Parkinson's disease because of secondary causes like the effect of certain drugs
• Drugs that cause pseudo-parkinsonism

  • Phenothiazines
  • Haloperidol
• Phenothiazines and haloperidol


  Anti-psychotic drugs
• High dopamine levels


  Lead to psychosis
• Low dopamine levels


  Lead to Parkinson's disease
• People with psychosis are given drugs that inhibit dopamine, which leads to pseudo-parkinsonism
• Drugs used to treat Parkinson's disease


  Provide temporary relief of symptoms, but do not treat the underlying cause
• Levodopa


  A precursor of dopamine that helps restore dopaminergic neurotransmission
• Carbidopa


  A suicide substrate that inhibits the enzyme that breaks down levodopa, allowing more to reach the brain
• Levodopa is effective for the first 2 years of treatment, but then the effects diminish over time
• Levodopa only provides temporary relief of Parkinson's disease symptoms
• Mechanism of action of levodopa

  It is transported to the brain and converted to dopamine
• Mechanism of action of carbidopa

  It inhibits the enzyme that breaks down levodopa, allowing more to reach the brain
• Levodopa should be taken on an empty stomach, as protein interferes with its transport to the brain
• Levodopa has a short half-life of 1-2 hours
• Long-term use of levodopa


  Leads to the "on-off" phenomenon where the effects diminish
• Adverse effects of levodopa

  • Anorexia
  • Nausea
  • Vomiting
  • Tachycardia
  • Ventricular extrasystoles
  • Hypotension
  • Mydriasis
  • Blood dyscrasias
  • False positive Coombs test
  • Brownish saliva and urine
• Levodopa


  Should not be given with vitamin B6 as it increases breakdown of levodopa
• Levodopa


  Should not be given with non-selective MAO inhibitors as it can lead to psychosis
• Levodopa


  Should be used with caution in cardiac patients as it can affect the heart
• MAO inhibitors


  Drugs that inhibit the enzyme that breaks down dopamine