Sympathomimetic agents, such pseudoephedrine and phenylephrine, can have the following side effects:
- Elevate blood pressure
- Elevate intraocular pressure,
- worsen existing urinary obstruction
- adversely interact with $-blockers, methyldopa, tricyclic antidepressants, oral hypoglycemic agents, and MAOIs.
- Increase heart rate.
**Sympathomimetic agents can be thought of as doing the same thing that anticholinergics do to the bladder since stimulating the sympathetic nervous system means you make it overpower the parasympathetic nervous system.
First-generation nonprescription antihistamines can enhance the anticholinergic and sedative effects of other medications.