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Anticholinergics (Parasympatholytics)

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By Iris Dawn Tabangcora, RN

Anticholinergics are drugs that oppose the effects of acetylcholine. In essence, they also lyse and block the effects of parasympathetic nervous system (PNS) so they are also called as parasympatholytics. Atropine is currently the only widely used anticholinergic drug. Other common examples include meclizine, scopolamine and ipratropium.

Table of Contents

Anticholinergics: Generic and Brand Names

Here is a table of commonly encountered anticholinergic agents, their generic names, and brand names:

  • Anticholinergics
    • atropine sulfate
    • ipratropium (Atrovent)
    • meclizine (Bonine, Antivert)
    • methscopolamine (Pamine)
    • scopolamine (Transderm Scop)
    • tiotropium (Spiriva)

Disease Spotlight: Gastrointestinal Ulcers

  • Anticholinergics were once very widely used to decrease GI activity and secretions. However, more specific and less toxic drugs are available now and the utilization of this drug class is now limited.
  • GI ulcers are basically erosions in the lining of the GIT caused by increased HCl production most commonly from H. pylori infection. Patients with GI ulcers suffer from burning abdominal pain, nausea, and acid reflux.

Therapeutic Action

The desired and beneficial actions of anticholinergics are as follows:

  • Competitively blocking the ACh receptors at muscarinic cholinergic receptor sites that are responsible for mediating the effects of the parasympathetic postganglionic impulses.
  • Atropine, the prototype drug, is derived from the plant belladonna. It is used to depress salivation and bronchial secretions and to dilate the bronchi, but it can thicken respiratory secretions (causing obstruction of airways).
  • Atropine and scopolamine work by blocking only the muscarinic effectors in the parasympathetic nervous system and the few cholinergic receptors in the SNS.


Anticholinergics are indicated for the following medical conditions:

  • Prevention of nausea, vomiting, and dizziness associated with motion sickness.
  • Adjunctive therapy for treatment of GI ulcers
  • Decrease secretions before anesthesia or intubation
  • Maintenance treatment of bronchospasm associated with COPD.
  • Treatment of irritable or hyperactive bowel in adults.

Here are some important aspects to remember for indication of anticholinergics in different age groups:



  • Adults should be cautioned of these drugs’ adverse effects.
  • Use of these drugs among pregnant women is not allowed because they can cross placenta and cause adverse effects to the fetus.

Older adults

  • Dose adjustment is needed as this age group is also more susceptible to drug side effects.
  • They are more likely to have toxic levels of the drug because of renal or hepatic impairments.


Here are the characteristic interactions of anticholinergics and the body in terms of absorption, distribution, metabolism, and excretion:

IM10-15 min30 min4 h
IVImmediate2-4 min4 h
SubcutaneousVaries1-2 h4 h
Topical5-10 min30-40 min7-14 d
Half-life (T1/2)MetabolismExcretion
2.5 hliverurine

Contraindications and Cautions

The following are contraindications and cautions for the use of anticholinergics:

  • Allergy to any component of the drug. To prevent hypersensitivity reaction
  • Glaucoma. Can be exacerbated by blockade of PNS.
  • Intestinal atony, paralytic ileus, GI obstruction. Can be exacerbated with further slowing of GI activity.
  • Pregnancy. Potential adverse effects on the fetus.

Adverse Effects

Use of anticholinergic agents may result to these adverse effects:

  • CNS: blurred vision, pupil dilation, photophobia, cycloplegia, increased intraocular pressure, weakness, dizziness, insomnia
  • CV: tachycardia, palpitation
  • GI: dry mouth, altered taste perception, nausea, heartburn, constipation
  • GU: urinary hesitancy and retention, heat prostration


The following are interactions involved in the use of anticholinergics:

  • Antihistamines, antiparkinsonisms, MAOIs, TCAs. These drugs also have anticholinergic effects so incidence of anticholinergic effects increases.
  • Phenothiazines. Decreased effectiveness of this drug.
  • Burdock, rosemary, turmeric. Risk for exacerbated anticholinergic agents

Nursing Considerations

Here are important nursing considerations when administering anticholinergics:

Nursing Assessment

These are the important things the nurse should include in conducting assessment, history taking, and examination:

  • Assess for contraindications or cautions (e.g., history of allergy to drug, GI obstruction, hepatorenal dysfunction, etc.) to avoid adverse effects.
  • Establish baseline physical assessment to monitor for any potential adverse effects.
  • Assess neurological status (e.g., orientation, affect, reflexes) to evaluate any CNS effects.
  • Assess abdomen (e.g., bowel sounds, bowel and bladder patterns, urinary output) to evaluate for GI and GU adverse effects.
  • Monitor laboratory test results to determine need for possible dose adjustments and to identify potential toxicity.

Nursing Diagnoses and Care Planning

Here are some of the nursing diagnoses that can be formulated in the use of this drug for therapy:

Implementation with Rationale

These are vital nursing interventions done in patients who are taking anticholinergics:

  • Ensure proper administration of the drug to ensure effective use and decrease the risk of adverse effects.
  • Monitor patient response (e.g., blood pressure, ECG, urine output) for changes that may indicate need to adjust dose.
  • Provide comfort measures (e.g., sugarless lozenges, lighting control, small and frequent meals) to help patient cope with drug effects.
  • Provide patient education about drug effects and warning signs to report to enhance knowledge about drug therapy and promote compliance.


Here are aspects of care that should be evaluated to determine effectiveness of drug therapy:

  • Monitor patient response to therapy (improvement in condition being treated).
  • Monitor for adverse effects (e.g., photophobia, heat intolerance, urinary retention).
  • Evaluate patient understanding on drug therapy by asking patient to name the drug, its indication, and adverse effects to watch for.
  • Monitor patient compliance to drug therapy.

Our recommended nursing pharmacology resources and books:

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See Also

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References and Sources

References and sources for this pharmacology guide for Anticholinergics:

  • Karch, A. M., & Karch. (2011). Focus on nursing pharmacology. Wolters Kluwer Health/Lippincott Williams & Wilkins. [Link]
  • Katzung, B. G. (2017). Basic and clinical pharmacology. McGraw-Hill Education.
  • Lehne, R. A., Moore, L. A., Crosby, L. J., & Hamilton, D. B. (2004). Pharmacology for nursing care.
  • Smeltzer, S. C., & Bare, B. G. (1992). Brunner & Suddarth’s textbook of medical-surgical nursing. Philadelphia: JB Lippincott.
Iris Dawn is a nurse writer in her 20s who is on the constant lookout for latest stories about Science. Her interests include Research and Medical-Surgical Nursing. She is currently furthering her studies and is seriously considering being a student as her profession. Life is spoiling her with spaghetti, acoustic playlists, libraries, and the beach.

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