Constipation (cont.)

Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.

A frequently over-looked cause of constipation is medications. The most common offending medications include:

• Narcotic pain medications such as codeine (for example, Tylenol #3), oxycodone (for example, Percocet), and hydromorphone (Dilaudid);
• Antidepressants such as amitriptyline (Elavil, Endep) and imipramine (Tofranil)
• Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
• Iron supplements
• Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
• Aluminum-containing antacids such as aluminum hydroxide suspension (Amphojel) and aluminum carbonate (Basaljel)

In addition to the medications listed above, there are many others that can cause constipation. Simple measures (for example, increasing dietary fiber) for treating the constipation caused by medications are often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a nonsteroidal ant-inflammatory drug (for example, ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating antidepressant medications (for example, fluoxetine [Prozac]) may be substituted for amitriptyline and imipramine.

Source: MedicineNet.com
http://www.medicinenet.com/constipation/article.htm