Anticholinergics: Medicines involved

Last updated: May 13, 2022

A whole range of medicines potentially have anticholinergic side effects and it is not possible to list all of them here. A review in BMC Geriatrics has a very extensive table if you'd like something more comprehensive and there's an alphabetical list on the ACB Calculator site. Note that sources can disagree about the strength of anticholinergic action of some medicines.

However, many medicines have only weak effects and/or are rarely used in practice. The commonly-prescribed medicines with more explicit anticholinergic actions include:

Analgesics for neuropathic pain

  • Tricyclic antidepressants such as amitriptyline, imipramine and nortriptyline are relatively potent anticholinergics, but carbamazepine has some action too.

Antidepressants

  • Tricyclic antidepressants such as amitriptyline, imipramine and nortriptyline are the worst offenders. SSRIs seem to have only minor anticholinergic actions, but paroxetine is generally considered the most potent.

Antiemetics and vertigo

  • Many of these have at least some anticholinergic action. Prochlorperazine, promethazine and hyoscine are examples with notable anticholinergic actions. Cyclizine and cinnarizine also have some anticholinergic activity.

Antihistamines

  • The older generation ones like chlorphenamine, promethazine, alimemazine and diphenhydramine have a stronger anticholinergic action than newer ones like loratadine and fexofenadine. 

Antipsychotics

  • Many of these have at least some anticholinergic action, although often it is the older agents like chlorpromazine and clozapine that are more potent. However, some newer agents like olanzapine have anticholinergic activity.

Gastrointestinal medicines

  • Medicines for gastrointestinal spasm such as dicycloverine (dicyclomine), hyoscine and propantheline have anticholinergic actions.
    • Over-the-counter medicines

    • Medicines with anticholinergic actions can be 'hidden' ingredients in over-the-counter medicines, such as medicines for insomnia, IBS, coughs and colds, migraine, allergy or travel sickness (e.g.  Benylin, Buccastem M, Buscopan, Kwells, Nytol, Phenergan, Stugeron)
      • Parkinson's medicines (and extrapyramidal symptoms)

        • Anticholinergic medicines to control movement disorders of this kind include procyclidine, orphenadrine, and trihexyphenidyl. Mental health patients with drug-induced Parkinsonism may also be taking these medicines. 

        Respiratory medicines

        • Bronchodilators such as glycopyrronium, ipratropium and tiotropium are anticholinergic drugs. Their side effect potential is much less than the other medicines cited here, mainly because they are given by inhalation.

        Urology medicines

        • Medicines for urinary incontinence and related symptoms such as oxybutynin, solifenacin, tolterodine, trospium, and propiverine have anticholinergic actions.

Even this incomplete summary is quite a lot of information to keep in your head. Later in this tutorial, we've provided an A4-sized poster you can print off and keep available for reference.


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