Patients should consult their physician before taking any additional prescriptions, over-the-counter medications, nutritional supplements or herbal medications. Taking central nervous system (CNS) depressants with antispasmodics can increase the effects of either the antispasmodic or the CNS depressant. Examples of CNS depressants include:

• Tricyclic antidepressants. Used to treat depression, anxiety or obsessional problems.
  
  
• Anti-anxiety drugs. Used to treat anxiety, tension and agitation.
  
  
• Antihistamines. Medications used to treat allergic reactions or allergies.
  
  
• Barbiturates. Drugs that produce relaxation and sleep.
  
  
• Narcotic pain relievers (opioids). Drugs that relieve severe pain.
  
  
• Alcohol.

Other drugs may also interact adversely with antispasmodics. Using multiple antispasmodics can change the desired effects of all drugs. Taking potassium chloride with antispasmodics may worsen gastrointestinal problems caused by potassium. Other medications of particular concern to individuals taking antispasmodics include antacids and diarrhea medicines containing kaolin or attapulgite. The antifungal drug ketaconazole can lessen the effects of antispasmodic drugs.