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NURSING FN/NURS 5334 Module 4 notes.
- CHOLINERGIC DRUGS: Turn on parasympathetic NS (SLUDGE) - Muscarinic Agonists- mimic effects of acetylcholine at muscarinic receptors DRUG NAME MOA USE AE Contraindicatio ns Drug interactions Bethanechol (^) Direct-acting muscarinic agonist. Binds reversibly to muscarinic cholinergic receptors to cause activation. At therapeutic doses, bethanechol acts selectively at muscarinic receptors, having little or no effect on nicotinic receptors, either in ganglia or in skeletal muscle. Urinary Retention GI (GERD),pos top abdominal distention (don’t give to GI obstruction) CV : hypotension, bradycardia (don’t give to hypotensive pts or low cardiac output) GI- excessive salivation, increased gastic acid, abdominal cramps, diarrhea GU- can pee (don’t give to UT obstruction/wea kness of bladder) Asthmatics Hyperthyroid ism Peptic Ulcer GI obstruction UT obstruction Drugs crosses Resp:
membrane poorly 10-50mg 3-4 times a day Bronchoconstric tion (don’t give to asthma pts) 1hr before meals or 2hrs after to prevent N&V Pupil constriction Cevimeline (^) Derivative of Ach, actions similar to those of bethanechol. Relief of xerostomia (dry mouth) in pts with Sjoren syndrome. Keratoconjuc tivit s sicca Excessive sweating Increases salivation Increase tear production Nause a Rhinit is Pupil Uncontrol led Asthma COPD Narrow angle glaucoma Iritis Use in caution Beta Blockers Atropine, TCA Antihistami nes Phenotiazin e antipsychot ics
Drug Name MO A
US
E
A
E
Contraindicatio ns Drug Interactions Neostigmine Neostigmine and other reversible cholinesteras e inhibitors act as substrates for cholinesteras e. Management of MG by strengthening muscles
SLUDGE
If administered in toxic dose, cholinesterase inhibitors can cause accumulation of Ach in amounts sufficient to produce GI and GU tract obstruction Peptic Ulcer Disease Asthma Muscari nic antagoni st Non- depolarizing neuromuscul ar blockers
depolarizing neuromuscular blockage. Paralysis of resp. muscle can be fatal. Coronary Insufficiency Hyperthyroidism Depolarizi ng neuromusc ular blockers Physostigmine Drug of choice for treating poisoning by atropine and other muscarinic blockade, including antihistamines and phenothiazine antipsychotics- but not tricyclic antidepressants Edrophonium A short and rapid- acting anticholineste rase Positively For Dx of MG
nerve gas Peptic Ulcer Disease Asthma Coronary Insufficiency Hyperthyroidism Donepezil Reversible Cholinester ase inhibitors Alzheimer Disease Galantamine Reversible Cholinester ase inhibitors Alzheimer Disease Rivastigmine Reversible Cholinester ase inhibitors Alzheimer Disease, dementia of Parkinson’s disease The irreversible cholinesterase inhibitors are highly toxic. These agents are employed primarily as insecticides and warfare_._ Highly lipid soluble. The only clinical indication for the irreversible inhibitors is glaucoma (Echothiophate)
-Toxic dose produce excessive muscarinic, nicotinic, and CNS effects (known as cholinergic crisis). -Cholinergic crisis is- excessive muscarinic stimulation and depolarizing neuromuscular blockage. Overstimulation of muscarinic receptors: SLUDGE, muscle weakness, fasciculations, cramps, twitching, paralysis, death from apnea, anxiety and confusion to delirium. Convulsions of CNS origin precede paralysis and apnea. Muscarinic (cholinergic) toxicity can be caused by either muscarinic agonists or cholinesterase inhibitors.
Bronchorr hea -Treatment is Atropine (antagonist) -Treatment: Atropine- to reduce muscarinic stimultions (SLUDGE), Pralidoxime reverse inhibition of cholinesterase, benzos (diazepam) for seizures, and mechanical vent for resp depression Pralidoxime: antidote for irreversible cholinesterase inhibitors, must be administered soon after organophosphate poisoning. Not effective for reversible inhibitors. MG: fluctuating muscle weakness and predisposition to rapid fatigue. Common symptoms of this are your ptosis, dysphasia and weakness of the skeletal muscles. And it's an auto-immune process where antibodies attack the nicotinic m receptors on the skeletal muscle.
Treatment: Cholinesterase inhibitors (Neostigmine) increase muscle strength can cause muscarinic response. start with small dose and adjust as needed. Modify dose in anticipation of exertion. Signs of under-medication Ptosis and difficulty swallowing. Signs of over-medications are excess of salivation and other muscarinic response. Differentiating between MG crisis and cholinergic crisis: If edrophonium-induced elevation of acetylcholine levels alleviates symptoms, the crisis is myasthenic. Conversely, if edrophonium intensifies symptoms, the crisis is cholinergic. Muscarinic Antagonists Muscarinic antagonists- selectively block the effects of acetylcholine at muscarinic receptors Drug Name MO A
US
E
A
E
Contraindicatio ns Drug Interactions Atropine IM, Preanesthetic Dry mouth (avoid Glaucoma Antihistami
muscarinic agonist poisoning peptic ulcer disease (when administered in high dose can cause SE) lights low, avoid driving) IOP Urinary retention (void before taking meds) Constipation (laxative, increase, increase fiber) Anhidrosis (absence of sweat) (avoid activities that might lead to overheating high risk for hyperthermia Tachycardia Asthma (can thicken secretions use with caution) bronchial secretions causing bronchial plugging
Oxybutynin Anticholiner gic acts primarily at M muscarinic receptors OAB (^) Dry mouth Constipation Tachycardia Urinary retention/hesit ancy Mydriasis (pupil dilation) Blurred vision Dry eyes Combined use of oxybutynin with other anticholinergic agents (e.g., antihistamines, tricyclic antidepressants, phenothiazine antipsychotics) can intensify all anticholinergic side effects. Drugs that inhibit or induce CYP3A4 may alter oxybutynin blood levels and may thereby either
darifenacin is combined with any of these, its dosage must be kept low. In patients with moderate liver impairment and in those taking powerful inhibitors of CYP3A4, dosage
should be kept low. Solifenacin (VESIcare) (5- 10mg daily) w/wo food OAB (^) Can cause prolong QT at high dose dry mouth, constipation, and blurred vision. Dyspepsia, urinary retention, headache, and nasal dryness Avoid w/pts in hepatic impairment levels of solifenacin can be increased by strong inhibitors of CYP3A4 (e.g., ketoconazol e, ritonavir, clarithromyc in). Tolterodine (^) Non- selective muscarinic antagonist OAB (^) Side effects are less with long active form Prolong QT ( should not exceed 4mg/day) Dose should be decreased for hepatic or renal impairment or those taking strong inhibitor CYP3A Anticholinergic effects can be intensified by concurrent use of other drugs with anticholinergic actions (e.g., antihistamines, tricyclic antidepressants, phenothiazine antipsychotics).
beneficial and adverse effects. Fesoterodine Non- selective muscarinic antagonist OAB (^) Dry mouth, Constipat ion In patients taking a strong inhibitor of CYP3A4 (e.g., ketoconazole, clarithromycin), beneficial and adverse effects are increased. Conversely, in patients taking a strong inducer of CYP3A4 (e.g., rifampin, carbamazepine), beneficial and adverse effects are reduced Trospium (^) Non- selective muscarinic antagonist OAB Dry mouth, constipation Vancomyc in Metformin Digoxin Procainam ide
-trospium is eliminated by the kidneys Scopolamine anticholinergic Emesis, motion sickness Ipratropi um Bromide anticholinergic (^) Asthma, COPD, rhinitis caused by allergies or common cold
