Direct-Acting Cholinergic Agonists
- Chemicals that act at the same site as the neurotransmitter acetylcholine (ACh)
- Similar response as parasympathetic system activation - Effects are widespread
- These drugs usually stimulate muscarinic receptors in PNS
- used as systemic agents used to:
- ↑ bladder tone, urinary excretion, & GI secretions
- also used as ophthalmic agents to induce miosis to relieve ↑ IOP of glaucoma via pupil constriction (not systemic when used ophthalmically)
- ↓ HR, ↓ myocardial contractility, bronchoconstriction & ↑ bronchial mucous secretion
- also used as ophthalmic agents to induce miosis to relieve ↑ IOP of glaucoma via pupil constriction (not systemic when used ophthalmically)
- ↓ HR, ↓ myocardial contractility, bronchoconstriction & ↑ bronchial mucous secretion
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Contraindications:
Caution:
Adverse Reactions:
3. Cevimiline (Exovac)
- Tx dry mouth
4. Pilocarpine (Salagen)
- Tx dry mouth (xerostomia) s/p radiation therapy of head & neck tumor
Nursing Mgmt
Baseline Assessment:
- Any condition that would be exacerbated by parasympathetic effects—bradycardia, hypotension, CAD
- PUD, intestinal obstruction or recent GI surgery
- Asthma
- Bladder obstruction
- Epilepsy & parkinsonism
Caution:
- pregnancy / lactation
- N/V, diarrhea, cramps, involuntary defecation
- Bradycardia, heart block, hypotension
- Urinary urgency
- Flushing, ↑ sweating & salivation, swallowing difficulty
Interactions:
Kinetics:
- ↑ risk of cholinergic effects if these drugs are combined or given with acetylcholinesterase inhibitors
Kinetics:
- Well absorbed and have relatively short half-life (1-6 hr)
- Metabolized; excretion of these drugs is not known
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Drugs:
1. Bethanechol (Duvoid, Urecholine)
- urinary retention
- urogenic bladder
- esophageal reflux in infants/kids
Mgmt:
Mgmt:
- Produces muscarinic effects primarily on GI tract & urinary bladder
- ↑ tone & peristaltic activity of esophagus, stomach, and intestine
- contracts detrusor muscle of urinary bladder, usually enough to initiate micturition.
- cant help if obstructed
- must monitor for effectiveness - i.e are they having problem still w/ urinary retention? (relief should be quick)
- if not working, could be structural problem (BUN & Cr will go way up)
2. Carbachol (Miostat)
- induces miosis to ↓ IOP
- induces miosis to ↓ IOP
3. Cevimiline (Exovac)
- Tx dry mouth
4. Pilocarpine (Salagen)
- Tx dry mouth (xerostomia) s/p radiation therapy of head & neck tumor
- glaucoma (constricts pupil & ↓ IOP)
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Baseline Assessment:
- Cardiovascular - HR, BP CAD
- GI - Bleeding, ulcer disease, obstruction, dehydration
- Respiratory assessment - Asthma
- GU - Recent bladder surgery or obstruction
- CNS - Parkinson’s and/or epilepsy
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