Does Tylenol Cause Constipation?
Tylenol (acetaminophen) is not typically associated with constipation as a common side effect, unlike opioid analgesics which are well-documented to cause constipation.
Evidence Assessment
The available guidelines and research provide limited direct evidence regarding acetaminophen and constipation. However, we can draw conclusions from what is available:
What the Evidence Shows:
The NCCN Palliative Care guidelines 1 and Adult Cancer Pain guidelines 1 extensively discuss constipation as a side effect of opioid analgesics but do not mention acetaminophen as a cause of constipation.
When listing medications known to cause constipation, the guidelines specifically mention:
- Opioid analgesics (most commonly associated)
- Antacids
- Anticholinergic drugs (antidepressants, antispasmodics, phenothiazines, haloperidol)
- Antiemetics
A 2023 study 2 mentions constipation as a potential side effect of acetaminophen at low doses, but this is mentioned briefly without substantial supporting evidence.
A 2007 epidemiological study 3 found an association between chronic constipation and acetaminophen use (≥7 tablets per week), with an odds ratio of 2.7 (1.1-6.6). However, this association doesn't necessarily prove causation.
Clinical Implications
Risk Assessment:
Low Risk: Acetaminophen has a significantly lower risk of causing constipation compared to opioid analgesics, which cause constipation in approximately 50% of patients with advanced cancer 1.
The primary concerns with acetaminophen are:
Management Considerations:
If a patient reports constipation while taking acetaminophen:
Rule out other causes: Consider other medications, dietary factors, dehydration, or underlying conditions.
Evaluate medication use: If the patient is taking ≥7 tablets of acetaminophen per week 3, consider this as a potential contributing factor.
Consider alternatives: If constipation persists and appears related to acetaminophen, consider alternative analgesics while weighing their own side effect profiles.
Practical Recommendations
Acetaminophen remains a preferred analgesic option for patients at high risk of constipation, especially compared to opioids.
For patients concerned about constipation:
- Ensure adequate hydration
- Maintain physical activity when possible
- Consider fiber intake if appropriate
If constipation develops while taking acetaminophen and other causes have been ruled out, consider reducing the dose or switching to an alternative analgesic, weighing the risks and benefits.
While there is some limited evidence suggesting a possible association between acetaminophen and constipation 3, this is not widely recognized as a common or significant side effect in major clinical guidelines, unlike the well-established constipating effects of opioids.