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