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Module 10 Pharm

Terms in this set (17)

-Functions​: break down cholinesterase enzyme into choline and acetic acid​, allow Acetylcholine to activate muscarinic and nicotinic cholinergic receptors​

-Desired therapeutic effect​: stimulate skeletal muscles, increase tone​, increased memory in Alzheimer's disease

-Contraindications : intestinal and urinary obstruction
-Use caution in patients with bradycardia, asthma, peptic ulcers​

-Side effects​: greater GI motility, bradycardia, miosis​• Bronchial constriction, promote urination​


-Cholinesterase is an enzyme responsible for breaking down acetylcholine.
-Indirect -acting cholinergic drugs inhibit cholinesterase.
-Inhibiting cholinesterase stops the break down of acetylcholine, leading to more available acetylcholine.
-The drug itself is not stimulating the cholinergic receptors, it is just allowing for more acetylcholine to be available to stimulate the cholinergic receptors.

-Donepezil and rivastigmine are cholinesterase inhibitors used to treat Alzheimer's disease. By allowing more acetylcholine in the CNS, it helps with memory recall. This does not cure Alzheimer's, however it does slow the progression of the disease.​

-Pyridostigmine is a cholinesterase inhibitor that is used for treatment of myasthenia gravis. It helps simulates skeletal muscles and increase tone.
-This treats the profound weakness in myasthenia gravis patients. In order to diagnose myasthenia gravis, edrophonium is used (it is ultra short acting).
-A patient with myasthenia gravis normally presents with a drooping eye (ptosis). The edrophonium is administered and the eye gets better (positive Tensilon test) which means the patient has myasthenia gravis. If the drooping doesn't get better (negative Tensilon test), this means the drooping eye is caused by something other than myasthenia gravis, which means they do not have myasthenia gravis.

-Toxicity and management of overdose: overdose of cholinergic drugs is called cholinergic crisis
-This can be life-threatening.
-Early signs will be abdominal cramps, salivation, flushing of the skin, nausea and vomiting. As the crisis continues, the heart will slow and may even have a complete heart block (the atria and the ventricle are asynchronously beating); airway will become compromised and blood pressure will decrease (orthostatic hypotension especially).
-So when you think about cholinergic crisis, I want you to think "DUMBELLS". If you observe DUMBELLS, what do you think the treatment would be?​
-If too much of a cholinergic drug caused the crisis, what kind of drug can fix the crisis? How about the opposite type of drug, a cholinergic antagonist, or anticholinergic drug? In this case, the drug is atropine.

-Interactions: antagonistic effects​ (anticholinergics (such as atropine)​, antihistamines (because they have anticholinergic properties)​, adrenergic agonists (epinephrine for example)), additive effects​ (ther cholinergic drugs)
-Scopolamine is a small patch placed behind the ear. It can be used to treat severe motion sickness. It can also be used preoperative to help prevent aspiration of secretions during surgery. I have also seen it used in hospice because it dries up the secretions at the back of the throat, therefore, helping decrease "death rattle" , the sound that is made when a dying person is breathing through the secretions at the back of their throat that they cannot expectorate.

-Benztropine is used to treat Parkinson's disease (decreases the tremors and rigidity), it can also be used to treat drug-induced EPS (Keep this in the back of your mind and we will talk more about that with the antipsychotic medications)

-Atropine is used for symptomatic bradycardia (the heart rate is slow, the patient is pale, diaphoretic, blood pressure low, perhaps they have passed out because their heart rate is so low); atropine can also be used preoperatively to decrease the secretions and decrease risk of aspiration in surgery.

-Tolterodine is used to treat overactive bladder.

-Ipratropium is used to treat asthma and COPD. It is a bronchodilator that has slower onset of action and prolonged duration of action when compared to albuterol.

-MOA: block the neurotransmitter acetylcholine at the muscarinic receptors

-Contraindications: glaucoma (dilated pupils increase the intraocular pressure and can cause blindness in patients with narrow-angle or closed-angle glaucoma), and myasthenia gravis (myasthenia gravis is treated with cholinergic agonists, a cholinergic antagonists (anticholinergic) would cause the disease to be uncontrolled, this leads to muscle weakness, and if severe, it could paralyze the diaphragm, causing the patient to stop breathing)

-Side effects: include tachycardia, palpitations, nasal congestion, flushing, photophobia, blurred vision, dry mouth and skin, abdominal distention and constipation, urinary retention, and impotence

-Interactions include: Additive effects with other anticholinergic drugs which could lead to toxicity. Increased effects of digoxin.

-Toxicity and management of overdose: Confusion (mad as a hatter), flushing of the skin (red as a beet), mildly elevated temperature (hot as a hare), dry mouth, dry skin (dry as a bone), pupil dilation, blurred vision (blind as a bat), anticholinergics cause urinary retention, so you can think "Full as a flask"

-Treatment normally is supportive care, for example hydration. The anticholinergic drug is stopped, and the body will return to normal with some time. If the patient has severe issues (hallucinations, coma, cardiac dysrhythmias) the patient may be administered physostigmine (a cholinergic drug). It is not routine to give this antidote because of the potential for severe side effects.
Assessments should include:
-Obtain vitals: Especially looking at heart rate and blood pressure
-Assess urine output as urinary retention may occur
-Obtain medical history: narrow-angle glaucoma, myasthenia gravis (both are contraindications of the drug)

Diagnosis:
-Constipation related to adverse effects of anticholinergic drugs.

Planning:
Outcome Identification:
-Heart rate will increase to 60-80 beats per minute after administration of atropine
-Patient empties bladder every 3-5 hours (tolterodine)
-The patient experiences less motion sickness while traveling (scopolamine).

Implementation:
-Monitor vital signs, looking for tachycardia
-Monitor I&O. Encourage to void prior to taking medication
-Assess Bowel function- can cause decrease peristalsis leading to constipation and paralytic ileus.
-Use a bed alarm because of the potential for confusion
-Provide frequent oral care for dry mouth
-Observe for signs and symptoms of anticholinergic toxicity

Patient teaching:
-Avoid heat and physical exertion, remember that there is decrease perspiration. This decreases the ability to cool body temperatures.
-Teach patient with MG and glaucoma to avoid atropine and atropine like drugs
-Wear sunglasses (Have you ever had your pupil's dilated at the optometrist? They always provide sunglass afterwards because the sunlight will cause pain when you walk outside) The patient will have photophobia because of the pupil dilation. It will hurt their eyes.
-Teach side effects
-Teach about how to help with dry mouth: Ice chips, hard candy, sugarless gum, and frequent oral care.
-Increase fluids, fiber and ambulation for constipation

Evaluation:
-It would depend on the anticholinergic drug we are administering: For example, decreased motion sickness after the administration of scopolamine. Make sure you know why the anticholinergic drugs would be administered, so that you can evaluate if the desired therapeutic response was achieved, or not.
-Always evaluate for side effects.
Assessments should include:
-Vital signs (blood pressure, heart rate); all the anti-Parkinson's Drugs cause orthostatic hypotension
-Depression and suicidal ideation (this is a depressing disease with poor long-term prognosis and suicide can be a risk and many of the drugs increase the chance of depression)
-Past medical history (glaucoma-contraindication for anticholinergic medications; hypertension-potential side effect with MAO-B inhibitors)
-Current prescribed medications: look at each anti-Parkinson's Drug and know which drugs or foods interact with each one.

Diagnosis:
-Urinary retention related to anticholinergic drug therapy and pathophysiologic changes related to Parkinson's disease
-Constipation related to changes in GI peristalsis related to Parkinson's disease and anticholinergic effects of medications.

Planning:
-Patient has less muscle rigidity and tremors.

Implementation:
-Monitor blood pressure throughout therapy, especially looking at positional blood pressure changes
-Selegiline can be administered oral or transdermal. If using a patch, clean the area of application, allow to dry, apply the patch and hold pressure for 30 seconds to help patch remain intact. Patch should be on patient for 24 hours. Only 1 selegiline patch should be on patient at a time. Rotate sites. Apply to torso, upper arm and upper thigh.

Patient education:
-Teach the patient to rise slowly, in stages to prevent orthostatic hypotension (amantadine and carbidopa-levodopa)
-Do not take carbidopa-levodopa with a high protein meal as this delays absorption of the medication. Take either half an hour before or an hour after. Split protein across all meals of the day.
-Drink 3 L of fluid per day to help prevent constipation
-Increase fiber intake to prevent constipation
-With MAO-B inhibitors, may need to limit intake of tyramine foods (aged cheese, wine, beer, etc)

Evaluation:
-The patient is able to participate in activities of daily living (less tremors and rigidity).