What over-the-counter (OTC) medications can cause urinary retention?

From the Guidelines

Over-the-counter (OTC) medications such as antihistamines, like diphenhydramine, and muscle relaxants, like cyclobenzaprine, can cause urinary retention due to their strong anticholinergic effects. These medications can interfere with the normal contraction of the bladder muscle or cause the urethral sphincter to tighten, making it difficult to empty the bladder completely 1. Some key points to consider include:

• Anticholinergic medications, such as oxybutynin, can have negative effects on urination, particularly in older adults, due to their broad muscarinic receptor blockade 1.
• The use of multiple anticholinergic drugs can lead to an "anticholinergic burden," which can adversely affect cognition and functionality in older patients 1.
• It is essential to be aware of the potential risks associated with anticholinergic and sedating medications, including injurious falls, episodes of confusion or delirium, visits to the emergency department, and hospitalizations 1.
• If you experience difficulty urinating, painful urination, or a sensation of incomplete bladder emptying while taking these medications, you should contact your healthcare provider promptly, as urinary retention can lead to urinary tract infections or kidney problems if left untreated. Key medications to watch out for include:
• Diphenhydramine
• Cyclobenzaprine
• Oxybutynin
• Other antihistamines and anticholinergic drugs found in OTC sleep aids and motion sickness medications.

From the FDA Drug Label

When using this product do not exceed recommended dosage Ask a doctor before use if you have ... trouble urinating due to an enlarged prostate gland

• Pseudoephedrine can cause urinary retention, especially in individuals with an enlarged prostate gland 2.
• It is recommended to ask a doctor before use if you have trouble urinating due to an enlarged prostate gland.

From the Research

OTC Meds that Can Cause Urinary Retention

The following over-the-counter (OTC) medications can cause urinary retention:

• Antihistamines, such as dimenhydrinate 3
• Anticholinergic respiratory agents, such as ipratropium 4
• Decongestants with alpha-adrenoceptor agonist activity
• Nonsteroidal anti-inflammatory drugs (NSAIDs) 5, 6
• Certain analgesics, such as opioids 5, 6

Mechanism of Action

These medications can cause urinary retention by:

• Blocking the action of acetylcholine, a neurotransmitter that helps to contract the bladder muscle 5, 6
• Increasing the tone of the urethral sphincter, making it harder to urinate 5, 6
• Reducing the sensitivity of the bladder to stretch, making it harder to feel the need to urinate 5, 6

Risk Factors

Certain individuals are at higher risk for developing urinary retention due to OTC medication use, including:

• Elderly patients, especially those with benign prostatic hyperplasia (BPH) 5, 4
• Patients with pre-existing urinary retention or other urinary disorders 5, 6
• Patients taking multiple medications that can cause urinary retention 5, 6