Parasympathetic Flashcards
Selective Muscarinic 1 R blocker
Pirenzepine
Selective M2 blocker
Gallamine
Choline esters:
Ach, methacholine, carbachol, bethanechol
Cholinomimetic alkaloids e.g
Pilocarpine
Indirect-acting drugs (anticholinesterases:
Reversible: neostigmine and physostigmine
Irreversible: organophosphates
(Sarine, somain parathione and malathione)
Ach
Quaternary ammonium
Must be given parenterally.
Non selective (Has both M and N action)
Not use clinically
Short duration
What are the specific modifications in cholinergic agonist
– the susceptibillity of the compounds to hydrolysis by cholinesterase
Alter the relative activity on muscarinic and nicotinic receptors
Obtain therapeutically useful drugs
T or F
All chline esters are tertiary ammonium compounds
F
All are quaternary
Methachloline uses
It is given parentrally s.c for treatment of :
Paroxysmal atrial tachycardia
Carbachol uses
Non selective and potent so it given to eye locllay for glucoma
Almost No major side effects.
Bethanechol uses
GI disorders (paralytic ileus) postoperative non-obstructive abdominal distension, gastric atony and retension and gastroparesis
UB: postpartum or postoperative non-obstructive urinary retention.
Route of A: orally
Adverse effects of bethanechol:
Due to generalized cholinergic stimulation:
Sweating, salivation, -BP & flushing (dt VD), nausea, abdominal pain, diarrhea and bronchospasm
Uses of pilocarpine:
Glucoma (sornger than carbachol because it is tertiary)
Hair growth
Atropine poisoning
Adverse effects of pilocarpine:
CNS disturbances (enters the brain)
Profuse sweating and salivation.
Contra I of muscarinic Agonists:
Brochial asthma
Peptic ulcer disease
Coronary A disease
Hypotension or marked bradycradia
GIT hyper-motility
Parkinsonism
Reversible Anti-cholinesterase:
A.alchohol with quaternary ammonium group : Endrophonium
B.carbamate derivatives : neostigmine (quaternary) and physostigmine (tertiary).
Uses of Edorphonium:
Diagnosis of myasthenia gravis
Antidote for curare and curare like-agents.
Treatment of supraventricular tachy-arrythmias (but CCB best)
Uses of reversible antiChE
Glucoma : physostigmine (eye d)
In anesthesia: Neostigmine (iv)
In intestinal and bladder atony : physostigmine & neostigmine
In treatment of myasthenia gravis
In atropine poisoning
Dif b/w neostigmine and physostigmine:
Quaternary—tertiary
Poorly absorbed—-lipid s well a
No BBB —–cross BBB
On S.M —– On M R, Gang &CNS
short essay about myasthenia gravis
An autoimmune disease, Ab formation against Nm- receptors of motor end plate
Characterized by muscle weakness with ++ fatigability resulting from failure of neuromuscular transmission
Treatment of myasthenia gravis:
Neostigmine (orally 2-4h)
Pyridostigmine (orally 3-6h)
Edrophonium for diagnosis
Removing ABs by plasma exchage
– ABs production by steroids or immunesuppressant
Reversible AntiChE with selective CNS effects:
Used in Alzheimer’s disease:
1.Tacrine (it has beem replaced because of ita hepatotoxicity).
2.Donepezil.
3.Rivastigmine
4.Galantamine
Irreversible AntiChE:
Organ phosphorous compound:
War gases: somain & sarine
Insecticides:malathione¶thio
Metrifonate:oralAnti-Schistosoma
Isoflurophate :eye iont. Glucoma
Echothiophate: eye drop in glucoma
Toxic manifest effects of irreversible ChE:
3 main types :
1.muscarinic :Dumbles
Nicotinic : muscle twiches & fasciculation, ++ adrenal medulla activity, tachycardia, cramping of S.M and HTN.
CNS: anxiety, restlessness, confusion, coma and depression of respiratory & CVS center
Cause of death in irreversible anti-ChE:
Respiratory failure (central & peripheral)
Managemant of acutre toxicity of Anti-ChE
Dermal decontamination & gastric lavage
Artificial respiration & suctioning of secretion
Supportive treatment
Toxin specific measures
Drugs used to treatment Oragonphosphorous poisoning:
1.Atropine to antagonize the muscarinic adverse effects
2.ChE reactivator : oxime
3.Pralidoxime (PAM) : (also reactivator 》 dephosphorylates AchE in the periphery) or Diacetylmonoxime
4.anti-convulsants e.g Diazepam
5.Fresh blood transfusion
Short assay about Diisopropylfluorophosphate (DFP):
Highly lipid soluble (well absorbed across all membranes, including skin.
Used topically for treatment of chronic open-angle glucoma
Diisopropylfluorophsophate (DFP) adverse effects:
Local irritation of eye & headache
DFP and Echothiophate:
Echothiphate highly polar (poorly absorbed from GIT & has negligible distribution into CNS)
Used as an aqueous solution for treatment of glucoma.
Has adverse effects like DFP but less
N.m blockers:
Vecuronium, tubocuarine and pancuronium
Antimuscarinic agents:
Atropin, ipratropium
Ganglion blockers:
Nicotine in high dose
T or F
Antimuscarinic or cholinergic antagonists block sympathetic neurons that are cholinergic innervated
T
T or F
Cholinergic antagonists can block nicotinic receptors:
F
They dont block nicotinic receptors, thus producing little or no action on skeletal neuromuscular junctions or autonomic ganglia.
Selective M3 blocker:
H.H.S.D (Hexa-Hydro-Sila-Difenidol)
Atropine causes B.D and decrease bronchial secretion.
What is the better drug for this action?
Ipratropium
Atropine at large dose decreases gastric motility (antispasmodic effect)
What is the better drug?
Pirenzepine
Atropine used in enuresis but there are better drugs:
TCA amd alpha-adrenergic antagonists
Atropine effects on Medulla:
Stimulation of the respiratory center and cardioinhibitory center and inhibitiom of the vomiting center
Atropine effects on basal ganglia:
Anti-parkinsonism
Atropine has ant-parkinsonism effects on basal ganglia but the …….. is more specific.
Benztropine
Uses of atropine:
1.Specific antidote for parasympathomimetic toxicity (organophosphorus poisoning, it is life saving)
2.Pre-anesthetic medication(4)
3.Heart block due to B-Blockers or digitalis.
4.in cases of vasovagal syncope dt excess vagal stimulation.
5.mydiatic for 2 puposes P32
6.peptic ulcer
7.intestinal and renal colic
8.diarrhea
9.nocturnal enuresis
10.hyperhydrosis
11.Vomiting and motion sickness
12.parkinsonism
Atropine used in intestinal and renal colic but …….. is more specific and for vomiting but …….. is better
Hyoscine butyl bromide
Hyscine
Atropine is used for nocturnal enuresis but ……… is better
Emepronium
Atropine adverse effects:
زغولة النشفة حبست جوزها بوسريع
+cycloplegia
Central excitation (irritability and hyperactivity)
Atropine toxicity:
Sever tachycardia and dilated pupil
Toxic psychosis
Respiratory depression may occu
Fever dt dryness
Abdominal distension dt paralysis of peristalsis
Retention of urine
Allergic manifestations.
Treatment of atropine toxicity:
- I.V physostigmine for ++ Ach cenrally and peripherally (BBB)
2.Diazepam iv for convulsions
3.in severe cases :artificial repirati
4.Stomach wash if taken orally
5.Ice bags and cold fomentations
Explain why?
Antipyretics are not effective in the case of atropine toxicity.
Because the sweating is inhibitrd.
Contraindications of atropine:
Fevers, Glucoma, bronchial Asthma, Tachycardia, Paralysis ileus, senile hypertrophy of prostate
After neostigmine as it may lead to severe Bradycardia.
Allergy to atropine
Hyoscine is similar to atropine but:
Has shorter duration
Mainly depressant effect on CNS leading to sedation & amnesia
More effective on eye
Less on heart and GIT (no tachy)
No local anodyne action on the skin or MM
Uses of hyoscine:
Pre-anesthetic medication
Prophylaxis of motion sickness
Parkinsonism & Meniere’s disease
Hyoscine is better than atropine in pre-anesthetic dt:
C.N.S depression and amnesia (less anesthetic is needed)
Stimulation of the R.C
Strong anti-secretory effect (prevent aspiration pneumonia)
No tachycardia, safe in thyrotoxic patients.
Atropine substitutes
Mydriatic cycloplegic group:
Eye drops :
Homatropine, tropicamide and cyclopentolate
Mydriatic but non cycloplegic atropine substitutes:
Eucatropine
Antisecretory & antispasmodic atropine substitutes:
Atropine methyl nitrate, hyoscine Butyle Bromide, oxphenonium, propantheline
Pirenzepine (gastrozepine) & telenzepine
Selective M1 blocker that inhibit gastric secretion
It is useful in peptic ulcer
In theraputic doses,they have antimuscarinic effects specific on GIT
In large doses ganglion blocking effects and neuromuscular blocking effects
Atropine methyl nitrate, hyoscine butyl bromide, oxphenonium, propantheline
Atropine substitutes specific on the urinary bladder:
Emepronium (cetriprin) & oxybutynin (uripan)
Quaternary ammonium compound
Antiasthmatic Atropine substitute affects s.m of the bronchi but doesn’t affect glands of the mucosa
Ipratropium
Antiparkinsonian Atropine substitutes:
Benzotropine (cogentin), trihexphendyle (artane)
Ganglion stimulant short assay:
1.Stimulate both symp and para
2.They are not in common use
3.in cause stim in low dose and vas versa
4
Ganglion stimulant their actions are similar to nicotine
May given intra umblical in neonatal asphyxia:
Lobeline
Nicotinic effects(MTWHF)
Mydriasis, Tachycardia, weakness, hypertension, fasciculations
T or F
Ganglion blockers are pure antagonists. They don’t produce initial stimulation
T
