Diphenhydramine (Benadryl) is a tertiary amine used for what? Mechanism?
Benadryl is an antiparkinsonian agent. Benadryl works via antimuscarinic mechanisms with anticholinergic effects
Tertiary vs quaternary amines?
Pharmicokinetics: Tertiary amines are non-polar amines. This means that they will get through lipid membranes, such as the BBB, and are easily absorbed. Quaternary drugs not as easily absorbed. Won’t penetrate BBB and enter CNS
What do anticholinergic drugs do? 3 categories?
Block action of ACh at cholinergic receptors (muscarinic and nicotinic) throughout the body.
- Muscarinic blockers - Parasympathetic
- Ganglionic blockers (nicotinic I) - parasympathetic & sympathetic
- Neuromuscular blockers (nicotinic II) - Skeletal muscle
The major pharmacological actions of anticholinergic drugs in the GI, Cardiovascular, eye, and urinary tract are what?
GI: Loss of muscle tone –> Constipation
Cardiovascular: Tachycardia
Eye: Relaxes ciliary and sphinctor muscles leading to an inability to accomodate & mydriasis (dilated pupils) respectively.
Urinary Tract: Urinary retention
Atropine and Scopolamine are the two major naturally occurring anticholinergic drugs. What receptor do they act upon?
Muscarinic cholinergic receptors in the parasympathetic system
What is the mechanism by which antimuscarinic, belladona alkaloids, work?
Blockade, via competitive antagonism, of acetylcholine at postsynaptic muscarinic receptors (parasympathetic).
-If concentration is pushed will also affect all autonomic system at ganglionic nicotinic receptors
Narrow-angle glaucoma contraindicates the use of what types of drug?
- Antimuscarinic (anticholinergic drugs)
2. Alpha 1 agonists
What defines antispasmodic drugs?
They are tertiary amines that have little anticholinesterase activity.
What of drug is dicyclomine (bentyl)? What is it used for?
It is antispasmodic antimuscarinic drug used for irritable bowel syndrome
What type of drug is tolterodine (Detrol)? What is it used for?
Tolterodine (Deltrol) is a antispasmodic antimuscarinic drug used to treat bladder instability (urinary leakage).
Tertiary amine, muscarinic blockers, mydriatics are used for what purpose?
To cause pupil dilation (mydriases) and cycloplegia for eye exams
What role do antiparkinsonian agents play in the treatment of parkinson symptoms? How do they do this?
Antiparkinsonian drugs, such as benadryl, are used to restore the balance b/t dopamine and ACh in the CNS. This is accomplished by blocking ACh production or increasing ACh degradation by various anticholinergic drugs.
Name two antimuscharinic, Antiparkinsonian drugs used in the initial treatment of parkinson symptoms.
- Benztropine (Cogentin)
2. Diphenhydramine (Benadryl)
What is the difference b/t depolarizing and non-depolarizing nglionic blocking agents? Give an example of each.
Depolarizing blocking agents initially activate ACh receptors and then hyperpolarize the receptors making further activation impossible. Non-competitive blocking agent. Ex = Nicotine
Non-depolarizing blocking agents are competitive inhibitors of ACh receptors. Ex = Mecamylamine (Inversine)
What is the general result of neuromuscular blocking agents?
Skeletal Muscle relaxants/muscle paralysis by blocking cholinergic impulses propogated from somatic motor neurons to skeletal muscle cells
skeletal muscles are not equally susceptible to the paralytic effects of neuromuscular blocking agents. What is the general order of pralaytic inducement?
- At low doses small muscles, such as in eye, eyelids, speech, swallowing& fingers.
- Limbs neck & trunk
- Respiration. Intercostal muscles
