Hypertension

Shock

Heart block

Asthma

Decongestant

Depression

The effects of these agents are complex and depend upon the specific receptor where the drugs exert their action.

Side Effects:

• High blood pressure
• Increased heart rate
• Depends on the receptor site where drugs exert effects

Receptor agonists which mimic the effects of endogenous chemicals (Norepinephrine and epinephrine) by combining with receptors in the sympathetic nervous system

Enhance the actions of the sympathetic nervous system

Examples:

Phenylephrine (Neosynephrine) alpha-1 receptors: Use - Nasal decongestion, vasoconstrictor

Clonidine (Catapres) alpha-2 receptors: Use - blood pressure

Dobutamine (Dobutrex) beta-1 receptors: Use - Increase cardiac output

Terbutaline (Brethine, Bricanyl) beta-2 receptors: Use - breathing

Pirbuterol (Maxair) beta-2 receptors: Use - breathing

Levalbuterol (Xopenex) beta-2 receptors: Use - breathing

Salmeterol (Serevent) beta-2 receptors:  Use - maintenance treatment asthma

Albuterol (Proventil, Ventolin) beta-2 receptors: Use - breathing

Epinephrine (Adrenalin) - Non-selective

Norepinephrine (Levophed) - Non-selective

Dopamine (Intropin) - Non-selective

Isoproterenol (Isuprel) - Non-selective

Facilitate the release of Norepinephrine or block the re-uptake of Norepinephrine in the neuronal membrane

Example: 

Amphetamines

Mechanism of Action:

Increase release of Norepinephrine

Example:

Tricyclic Antidepressants

Mechanism of Action:

Block re-uptake of Norepinephrine

Uses:

Hypertension

Heart disease

Migraine headaches

Mechanism of Action:

Oppose the action of the natural messengers, epinephrine and Norepinephrine, as their receptor sites

Often referred to as adrenergic antagonists (blockers)

Side Effects:

Dizziness

Fainting

Nasal stuffiness

Beta Blockers:

Propranolol (Inderal) - Can block B2 Receptors

Atenolol (Tenormin)

Metoprolol (Lopressor)

Nadolol (Corgard)

Timolol (Blocadren)

Acebutolol (Sectral)

Selectivity:

B-1 receptors affect heart

B-2 receptors affect lungs

Alpha Blockers:

Ergotamine (used for migraine headaches)

Prazosin (Minipress):

Use: Blood Pressure.

Terazosin (Hytrin):

Use: Blood Pressure.

Phenoxybenzamine (Dibenzyline)

Doxazosin (Cardura)

Use: Blood Pressure

Tamsulosin (Flomax)

Use:  treat Benign Prostatoc Hyperplasia (enlarged Prostate)

Alfuzoxin (Uroxatral)

Use:  treat Benign Prostatoc Hyperplasia (enlarged Prostate)

Labetalol (Trandate) 

Use: Blood pressure

Carvedilol ( Coreg)

Use: Blood Pressure

Uses:

Glaucoma

Bladder problems

Gastrointestinal problems

Alzheimer's disease

Mechanism of Action:

• Salvation
• Lacrimation
• Urination
• Defecation

• Mimic actions of Acetylcholine
• Enhance the actions of the parasympathetic nervous system
• Opposes the effects of the sympathetic nervous system
• May be direct action on cholinergic receptors or an indirect action through inhibition of enzymes that destroy Acetylcholine

Side Effects:

• Diarrhea
• Bradycardia
• Miosis
• Decreased blood pressure
• Bronchoconstriction
• Sweating

Examples:

Pilocarpine (Pilocar):

Use: Glaucoma decrease interouclar pressure

Bethanechol (Urecholine)

Use: Bladder problems

Endrophonium (Tensilon)

Physostigmine (Antilirium)

Carbachol (Miostat)

Acetylcholine

Donepezil (Aricept) use: to treat Alzheimer

Neostigmine (Prostigmin)

Pyridostigmine (Mestinon)

Tacrine (Cognex) use: to treat Alzheimer

Rivastigmine (Exelon)  use: to treat Alzheimer

Uses:

• Anti-spasmodics
• Anti-Parkinsonism
• Bronchial disorders
• Eye exams
• Motion sickness

Mechanism of Action:

• Inhibit or reverse the actions of the parasympathetic nervous system
• Bind with the cholinergic receptors and prevent binding of Acetylcholine (they are antagonists)

Side Effects:

• Urinary retention
• Tachycardia
• Dry mouth
• Constipation
• Mydriasis

Examples:

Atropine

Benztropine (Cogentin)

Scopolamine (Transderm-Scop): Use - Motion sickness

Cyclopentolate (Cyclogyl): Use - dilates pupils of eyes

Hyoscyamine (Anaspaz, Levbid, Levsin)

Ipratropium (Atrovent)

Procyclidine (Kemadrin)

Propantheline (Pro-Banthine)

Trihexyphenidyl (Artane)

Uses:

• Preoperative skeletal muscle relaxation

Mechanism of Action:

• Blocks the transmission of nerve impulses to skeletal muscles resulting in paralysis of skeletal muscle
• There is a narrow therapeutic index with these agents.  When these drugs are used, life sustaining respiratory support equipment must be available.

Examples:  (Used mainly in hospitals)

• Cisatracurium (Nimbex)
• Succinylcholine (Anectine)
• Pancuronium (Pavulon)
• Vecuronium (Norcuron)
• Mivacurium (Mivacron)
• Rocuronium (Zemuron)

Local Anesthetic:

Uses:

Minor surgery

Mechanism of Action:

Block conduction of impulses along nerves and prevents the sensation of pain from reaching brain

Side Effects:

Allergy

Examples:

Lidocaine (Xylocaine)

Benzocaine (Anbesol, Benzodent, Lanacane, Orajel, Solarcaine)

Tetracaine (Pontocaine)

Bupivacaine (Marcaine)

Cocaine

Dibucaine (Nupercainal)