VPT 321: Veterinary Neuropharmacology (2+1)

THERAPEUTIC USES

Atropine and the other muscarinic receptor antagonists  are indicated in various clinical conditions.

Antispasmodic

• As antispasmodic it can be used to control gastrointestinal hypermotility and hypertonicity of the uterus , urinary bladder,  ureter, bile duct and bronchioles. But  in the bronchiolar spasm it is not as effective as adrenergic drugs.

 Preanaesthetic

• Used as an adjunct to general anaesthesia as it reduces the salivary and airway secretions.
• However, in cattle its use may result in inappetance and rumen stasis. In addition to the reduction in secretions these drugs also block the vagal reflexes to the heart during anaesthesia.
• Scopolamine causes tranquility and amnesia because of its central actions.
• With morphine, scopolamine produces analgesia and amnesia.
• Glycopyrrolate is preferred as a preanaesthetic because of its less significant  effect on the heart.

 Ophthalmology

• Used to dilate the pupils and paralyze accommodation in the treatment of various inflammatory conditions of the eye and as an aid to ophthalmoscopic examination.
• Atropine is no longer a drug of choice for producing mydriasis or cycloplegia as its effects are too long lasting.
• Homatropine is the drug of choice for producing mydriasis as it produces only weak cycloplegia.
• Cyclopentolate and tropicamide were developed specifically for ophthalmic use and have rapid recovery times.

 Antidote for anticholinesterase poisoning and over dosage 

•  Used as an antidote in the treatment of poisoning by  cholinestrase inhibitors like carbamates and organophosphorus compounds. 

Other uses

• Acute rhinitis, hay fever, motion sickness, myasthenia gravis and common cold.