What is a pill imprinted mylan 129?

Mylan 199 is 0.3 milligrams of Clonidine HCl.

According to the Drugs.Com Website, Clonidine is used for the following:

Treating severe pain. Clonidine is used with opiates in cancer patients for whom opioid (narcotic) analgesics alone have not been adequately effective. It may also be used for other conditions as determined by your doctor.

Clonidine is an alpha agonist analgesic. It works in the spinal cord by preventing pain signal transmission to the brain.

First of all, according to the Drugs.Com, Clonidine is used to treat hypertension. It

decreases the levels of certain chemicals in your blood. This allows your blood vessels to relax and your heart to beat more slowly and easily.

As for other uses which include: relieving alcohol withdrawal, methadone and opiate detoxification, quitting smoking, treatment of diabetic diarrhea, treatment of Tourette's Syndrome, reducing menopausal flushing, treat of postherpetic neuralgia, and treatment of ulcerative colitis, they are not approved by FDA, although Clonidine can be prescribed for them, too.

Clonidine is also marketed under brand names Catapres and Duraclon.