Pages

Thursday, 13 August 2020

Cholinergic Drugs

 

Cholinergic Drugs


Direct acting cholinergic drugs (receptor activator)

Natural:

Drugs

Receptor type                       

Clinical uses

Pilocarpine

m+n                                         

Produce myosis

Arecoline   

m+n

Produce myosis

Muscarine

m

No use

Synthetic:

Drug

Receptor type

Clinical use (Produce)

Acetylcholine (proto type)

M+n

No use

Methacoline

M+little n

Atrial tachycardia

Carbacol

M+n

Ecbolic effect, myosis, Rx for intestinal impaction,

Bethanicol

m

Rx atony in bladder

 

Indirectly acting cholinergic drugs (cholinesterase inhibitor)

Reversible inhibitors

          Drug                                                                     Clinical uses

Edrophonium

Diagnosis of myasthenia gravis

Physostigmine (BBB)

↑GIT, ↑UB, Rx atropine toxicity, myosis

Neostigmine

Antidote for NM blockers,Rx myasthenia gravis, myosis, ↑GIT

Pyridostigmine

Rx chronic myasthenia gravis

Carbaryl compounds

Myosis, ↑GIT   


Irreversible
inhibitors (Organophosphate)

Drugs

Clinical uses

Diisoflorophosphate (isoflorophate)

Rx chronic open angle glaucoma

Tetraethylpyrophospahte (TEPP)

As above

Echothiophate

As above

Serine (nerve Gas)

As above

Parathion, melathion

Insecticides

Coumaphos (Asuntol),tricholrophon (neguvan)

Ectoparasitesites

Diclorvos (Ivermectin)

endoparasitesites


Cholinergic blocking agent (parasympatholytic)

Natural

Drugs (don’t block n receptors)

Clinical Uses

Atropine (proto type drug)

Antispasmodic, preanesthetic, ↓secretions, antidote for organophosphate, produce mydriasis (cycloplagia)

Scopolamine (BBB)

↓GIT in horses, mydriasis, sedative effect

Belladonna extract

Same

 

 Semi synthetic (atropine analogues)

Drug

Clinical uses

Homatropin

Poor mydriasis (cycloplagia)

Eucatropin

Poor mydriasis no cyclopalgia

Methyl scopolamine

As above

Methatropin

As above

Synthetic drugs

Drug

Clinical uses

Glycopyrolate

Preanaesthetic in Horses

Pirenzapine

Rx gastric ulcer, mydriasis no cyclopalgia

Tropicamide

Mydriasis

Propenthiline

Anti-diarrhoel, anti-colic pain


Adrenergic drugs

Direct acting (receptor activator)

Natural

Drugs

Receptor

Clinical uses

Epinephrine

α1,β1, α2, β2

Rx asthma, shock  open angle glaucoma, ↑ anesthetic period

Nor-epinephrine

α1,β1, α2

Rx shock

Dopamine

β1

Same


Synthetic drugs (α agonist)

Drug

Receptor

Clinical uses

Phenylephrine

α1

Rx nasal decongestant, produce tachycardia

Phenylpropanolamine

α1

Same

Methoxamin

α1

Same

Clonidine

α2

Tranqlizer effect

Xylazine

α2

Tranqlizer effect

Detomidine

α2

Tranqlizer effect

Medetomidine

α2

Tranqlizer effect


β agonist

Drug

Receptor

Clinical uses

Isoproterenol (isoprenaline)

β1 β2

Bronchodilator, ↑ force of contraction of heart  

Dobutamine

β1

Rx congestive heart failure

Terbutaline

β2

Bronchodilator

Salbutamol

β2

Bronchodilator

Clenbutarol

β2

Bronchodilator, growth promoter

Metaproterenol

β2

Bronchodilator

Salmetrol

β2

Bronchodilator

Albutarol

β2

Bronchodilator

Ritodrine

β2

Bronchodilator

Isoruprine

β2

Tocolysis (delayed parturation)


Indirectly acting adrenergic drugs

Releasers (team)

Drug

Clinical uses

Tyramine

Rx asthma, nasal decongestant, shock

Ephedrine

Rx asthma, nasal decongestant, shock

Amphetamine

CNS stimulator

Meteraminol

Rx asthma, nasal decongestant, shock


Re-uptake inhibitor

Drug

Clinical uses

Cocaine

Same as releasers

Triplanamine

Same as releasers

Imipramine

Same as releasers


MAO inhibitors

Drugs

Clinical uses

Tranylcypramine

Same as releasers

Isocarboxazide

Same as releasers

Phenalzine

Same as releasers


Adrenergic blocking agent

α antagonist

Drug

Receptors

Clinical uses

Phenoxybenzamine (dibenzyline)

α1  α2

Rx 4 pheocromocytoma, ↓BP, cause myosis

Phentolamine

α1  α2

↑GIT and secretions, diagonosis of pheocromocytoma

Azaptin

α1  α2

Same

Peperoxon

α1  α2

↓BP

Prazosin

α1

↓BP

Terazasin

α1

↓BP

Doxazosin

α1

↓BP

Ergotamine

α1

↓BP

Phenothiazine traqlizer (acepromazine)

α1

↓BP

Tolazolin

α2

Antidote for α2 agonist

Yohimbine

α2

Antidote for α2 agonist


β blockers

Used for treatment of angina pectoris, cardiac arrthymias, myocardial infarction, migraine, headache and glaucoma

Drug

Receptor

Clinical uses

Labetalol

α1,β1, α2, β2

Rx for hypertension, glaucoma

Propanolol

β1 β2

↓BP, glaucoma

Timolol

β1 β2

↓BP

Nidolol

β1 β2

Glaucoma, ↓BP

Oxprinolol

β1 β2

Glaucoma, ↓BP

Pindolol

β1 β2

Glaucoma, ↓BP

Atenolol

β1

↓BP

Acebutalol

β1

↓BP

Metoprolol

β1

↓BP

Esmolol

β1

↓BP

Butaxamin

β2

Bronchoconstrictor


Ganglionic stimulant

'         Nicotine (at low doses gangloinic stimulant, at high G blockers)

'         Lobeline

Gangloinic blockers

'         Hexamethonium

'         Pentamethonium

'         Tetraethylammonium

'         Trimethaphane (in human ↓BP)

'         Mecammylamine (in human ↓BP)

 

Neuromuscular blocking agents (muscle relaxants)

Stablizers (non depolizer and competitive)

Detubocurarine

In surgery to relax muscle

Metocurarine

Gallamine

Pencronium

Alcuronium

Vecoronium

Fazadinium

 

Depolizers (non stabilizer, non competative)

Decamethonium

To avoid gastric content during operation 

 

Sexamethonium (saccenylcholine) (prototype drug)

 

Enzyme reactivator

'         Pralidoxime (2-PAM)

'         Obidoxime

 

Neurotransmitter blockers (binders)

'         Reserpine (Does not allow NT to go into vesicle)

'         Guanethidine, bretylium (Do not allow NT to come out from vesicle)

'         Cocaine (Does not allow re-uptake of NT in nerve endings)

Organs and the receptors

Receptor

Organ

Receptor

Organ

Receptor

Organ

β1

Heart

β2

SM of BV

β2

Sk Mus  BV

β2

Lungs, Uterus 

β2

Urinary bladder

α2

Presynaptic Membrane

α1

BV

α1

Sphincters

α1

Radial muscle eye


Proto type drugs

  1. Acetylcholine
  2. Atropine
  3. Tubocurarine
  4. Sexamethanium
  5. Primidine
  6. Chloral hydrate
  7. Chlorpromazine
  8. Morphine

No comments:

Post a Comment