Autonomic Antagonists

Atropine sulfate îs administered how?

IV, IM, SC

What are labeled uses of Atropine sulfate?

Pre-anesthetic to reduce bronchial secretions

Sinus bradycardia, sinoatrial arrest, Incomplete AV block

DX vagally mediated bradycardia

Cholinergic agonist toxicity

What are the pharmicodymaics of Atropine sulfate?

Competitive antagonist of M receptors (Will have sympathetic effects blocking parasympathetic receptors)

How is Atropine sulfate distributed?

CNS milk placenta

How is Atropine sulfate excreted?

Urinary 1/2 life of 1hr (should only give once at beginning in cases of cardiac arrest)

What are adverse effects of Atropine sulfate?

Arrhythmias

Decreased GI motility

How does Atropine sulfate affect the eye?

Pupillary dilation - No response to changes of brightness

Unable to focus eyes

Secretory inhibition

Increases IPO

What are indications of Atropine sulfate in local administration to the eye?

Pain

Dilation for intraocular surgery

Synechiae breakdown

Atropine sulfate when given intraocular is ___ and possible to cause ____ in horses"

LONG LASTING

Colic in horses

What is the drug of choice for Funduscopic exams? Why?

Tropicamide - lower half life

What is the labeled use for Glycopyrrolate?

Premed for dogs and cats

What is extra labeled use for Glycopyrrolate?

Premed for ferrets,

Bradycardia in anything that isn't livestock

Glycopyrrolate is only given ___ because it has a reduced ____ and can't?

IV,

Vd

Can't pass mucus membranes because it is CHARGED

Oxybutynin chloride is extra-labeled for?

Detrusor hyperreflexia in dogs and cats

What is Detrusor hyperreflexia?

Reduces urination by relaxing the tursor muscles that squeeze the urine out.

How is Oxybutynin chloride given? Why?

PO

Very good absorption b/c non polar molecule (gets everywhere)

What animals would we not give Oxybutynin chloride to?

CV dz

Glaucoma

Colicing horse

What are the indications for prazosin?

Hypertension - cats and dogs

Functional urethrospasm - cats and dogs

CHF management - dogs

What are the pharmicodynamics of prazosin?

Competitive a1 inhibitor

How does prazosin help with urination?

Relaxes the prostate and the trigon by blocking NE from binding to A1 receptors resulting in the pet being able to urinate

How is prazosin administered and excreted?

PO administration

Biliary - excretion

What are the indicated usages of Phenoxybenzamine HCl?

Urethrospasm in dogs cats and horses

Phenochoromocytomas

What are the pharmicodymanics of Phenoxybenzamine HCl>

Non-competative a1 inhibitor (non reversible)

With Phenoxybenzamine HCl we can see an increase in ____ but we will not see an increase in ____?

HR

BP

(B1 is still functioning in the heart meaning elevated HR and Constractility)

What is a Pheochromocytoma?

A tumor releasing NE and E episodically which can lead

Hypertension

Tachycardia

Arrhythmia

When should we administer Phenoxybenzamine HCl when treating a Pheochromocytoma?

Initial tx and

Perioperatively

How is Phenoxybenzamine HCl administered and where is it excreted?

Administered PO w/ low bioavalibilty

Excreted in urine and bile

What are Adverse effects of A1 antagonists?

Hypotension

2ndary syncope

Reflex tachycardia

Nasal congestion

Miosis/ Increased IOP

Inhibition of ejaculation

What are contraindications of a1 antagonists?

CHF

Pre-existing hypotension

CRF

Colic

Glaucoma