McKenna's Pharmacology for Nursing, 2e

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C H A P T E R 3 3 Anticholinergic agents

CHAPTER SUMMARY ■■ Anticholinergic drugs, also called parasympatholytic drugs, block the effects of acetylcholine at cholinergic receptor sites, thus blocking the effects of the parasympathetic nervous system. ■■ Parasympathetic nervous system blockade causes an increase in heart rate, decrease in GI activity, decrease in urinary bladder tone and function, and pupil dilation and cycloplegia. ■■ These drugs also block cholinergic receptors in the CNS and sympathetic postganglionic cholinergic receptors, including those that cause sweating. ■■ Many systemic adverse effects associated with the use of anti–cholinergic drugs are due to the systemic cholinergic blocking effects that also produce the desired therapeutic effect. ■■ Atropine is the most commonly used anticholinergic drug. It is indicated for a wide variety of conditions and is available in oral, parenteral and topical forms. Monitor for adverse effects: CV effects—tachycardia, heart failure; CNS—confusion, dreams; urinary retention; GI effects—constipation; visual blurring, photophobia. Monitor for drug–drug interactions as indicated for each drug. Evaluate effectiveness of teaching program and comfort and safety measures. TEACHING FOR E.K. • Anticholinergics are drugs that block or stop the actions of a group of nerves that are part of the parasympathetic nervous system. These drugs may decrease the activity of your GI tract, dilate your pupils, or speed up your heart. • Some of the following adverse effects may occur: • Dry mouth, difficulty swallowing : Frequent mouth care will help to remove dried secretions and keep the mouth fresh. Sucking on sugarless lollies will help to keep the mouth moist. Taking lots of fluids with meals (unless you are on fluid restriction) will help swallowing. • Blurred vision, sensitivity to light : If your vision is blurred, avoid driving, operating hazardous machinery, or doing close work that requires attention to detail until your vision returns to normal. Dark glasses will help to protect your eyes from the light. • Retention of urine : Take the drug just after you have emptied your bladder. Moderate your fluid intake while

■■ Individuals receiving anticholinergic drugs must be monitored for dry mouth, difficulty swallowing, constipation, urinary retention, tachycardia, pupil dilation and photophobia, cycloplegia and blurring of vision, and heat intolerance caused by a decrease in sweating. the drug’s effects are the highest; if possible, take the drug before bedtime, when this effect will not be a problem. • Constipation : Include fluid and fibre in your diet, and follow any bowel regimen that you may have. Monitor your bowel movements so that appropriate laxatives can be taken if necessary. • Flushing, intolerance to heat, decreased sweating : This drug blocks sweating, which is your body’s way of cooling off. This places you at increased risk for heat stroke. Avoid extremes of temperature, dress coolly on very warm days, and avoid exercise as much as possible. • Report any of the following to your healthcare provider: eye pain, skin rash, fever, rapid heartbeat, chest pain, difficulty breathing, agitation or mood changes (a dose adjustment may help to alleviate this problem). • Avoid the use of over-the-counter medications, especially for sleep and nasal congestion; avoid antihistamines, diet pills and cold capsules. These products may contain drugs that cause similar anticholinergic effects, which could cause a severe reaction. Consult with your healthcare provider if you feel that you need medication for symptomatic relief. • Tell any doctor, nurse or other healthcare provider involved in your care that you are taking these drugs. • Keep these drugs, and all medications, out of the reach of children. Do not share these drugs with other people.

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