Metformin is notorious for causing intestinal trouble. Ask his doc about the extended release (ER) version; sometimes that's tolerated better.

Look up Gastroparesis. It is a common complication of poorly controlled diabetes.

Here is an excerpt from Web MD:


Gastroparesis is a condition in which your stomach cannot empty itself of food in a normal fashion. It is caused by damage to the vagus nerve, which regulates the digestive system. A damaged vagus nerve prevents the muscles in the stomach and intestine from functioning, preventing food from moving through the digestive system properly. Often, the cause of gastroparesis is unknown.

However, the causes of gastroparesis can include:

Uncontrolled diabetes
Gastric surgery with injury to the vagus nerve
Medications such as narcotics and some antidepressants
Parkinson's disease
Multiple sclerosis
Rare conditions such as: Amyloidosis (deposits of protein fibers in tissues and organs) and scleroderma (a connective tissue disorder that affects the skin, blood vessels, skeletal muscles, and internal organs)


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What Are the Symptoms of Gastroparesis?

There are many symptoms of gastroparesis, including:

Heartburn or GERD
Nausea
Vomiting undigested food
Feeling full quickly when eating
Abdominal bloating
Poor appetite and weight loss
Poor blood sugar control

What Is the Treatment for Gastroparesis?

Gastroparesis is a chronic (long-lasting) condition. This means that treatment usually doesn't cure the disease. But there are steps you can take to manage and control the condition.

Some patients may benefit from medications, including:

Reglan (metoclopramide): You take this drug before eating and it causes the stomach muscles to contract and move food along. Reglan also decreases the incidence of vomiting and nausea. Side effects include diarrhea, drowsiness, anxiety, and, rarely, a serious neurological disorder.
Erythromycin: This is an antibiotic that also causes stomach contractions and helps move food out. Side effects include diarrhea and development of resistant bacteria from prolonged exposure to the antibiotic.
Antiemetics: These are drugs that help control nausea.
People who have diabetes should try to control their blood sugar levels to minimize the problems of gastroparesis.

Dietary Modifications for Gastroparesis

One of the best ways to help control the symptoms of gastroparesis is to modify your daily eating habits. For instance, instead of three meals a day, eat six small meals. In this way, there is less food in the stomach; you won't feel as full, and it will be easier for the food to leave your stomach. Another important factor is the consistency of food; liquids and low residue foods are encouraged (for example, applesauce should replace whole apples with intact skins).

You should also avoid foods that are high in fat (which can slow down digestion) and fiber (which is difficult to digest).


Whatever it is you should consult a doctor sooner rather than later