Can oxybutynin (antimuscarinic) increase blood pressure (hypertension)?

Oxybutynin Can Increase Blood Pressure

Yes, oxybutynin can increase blood pressure due to its anticholinergic properties, though it is more commonly associated with orthostatic hypotension. 1

Mechanism of Action and Blood Pressure Effects

• Oxybutynin is an anticholinergic medication commonly used for overactive bladder that can cause both orthostatic hypotension and, less commonly, hypertension 1
• The FDA label for oxybutynin specifically warns that it "may aggravate the symptoms of hyperthyroidism, coronary heart disease, congestive heart failure, cardiac arrhythmias, hiatal hernia, tachycardia, hypertension, myasthenia gravis, and prostatic hypertrophy" 2
• Anticholinergic medications like oxybutynin are considered "strongly anticholinergic" and are often poorly tolerated in elderly patients due to their broad muscarinic receptor blockade 3

Risk Factors for Blood Pressure Changes

• Elderly patients are more susceptible to blood pressure fluctuations with anticholinergic medications like oxybutynin 1
• Patients with higher baseline blood pressure may experience greater increases when taking oxybutynin 1
• The "anticholinergic burden" from taking multiple anticholinergic drugs can adversely affect cognition and functionality, and may exacerbate cardiovascular effects 3

Clinical Considerations

• Orthostatic hypotension is more common than hypertension with oxybutynin, particularly in elderly patients and those taking other medications with cardiovascular effects 1
• The Drug Burden Index shows that drugs with strong anticholinergic properties (like oxybutynin) are associated with decline in cognition, functional status, and activities of daily living scores in older patients 3
• Patients with pre-existing cardiovascular conditions require careful monitoring when taking oxybutynin 2

Monitoring Recommendations

• Blood pressure monitoring is recommended at baseline before starting therapy, during dose adjustments, and periodically during maintenance therapy 1
• Monitor for signs of orthostatic hypotension and check blood pressure in both seated and standing positions when initiating therapy 1
• Consider more frequent monitoring in patients with pre-existing cardiovascular disease or hypertension 1

Management of Blood Pressure Effects

• For patients experiencing hypertension with oxybutynin, RAS-inhibitors and diuretics are preferred due to fewer pharmacological interactions with anticholinergic medications 1
• If blood pressure changes are significant, consider alternative medications for overactive bladder with fewer anticholinergic effects 3
• In patients with spina bifida requiring anticholinergic therapy, regular blood pressure monitoring is essential 3

Alternative Administration Routes

• Intravesical administration of oxybutynin may reduce systemic anticholinergic side effects while maintaining efficacy for bladder control 4
• Vaginal inserts containing oxybutynin have been studied as an alternative delivery method that may produce more stable blood levels with fewer systemic effects 5

Special Considerations for Deprescribing

• Oxybutynin is listed among medications that should be considered for deprescribing in older adults due to its strong anticholinergic effects and potential for adverse events 3
• When deprescribing antihypertensives, careful monitoring is needed, especially in patients also taking medications like oxybutynin that may affect blood pressure 3