Is there any medicine available for painless varicose veins in the leg? Any yoga?

Not really. Prescription compression stockings, that are stronger than ted hose, can help to control the symptoms caused by varicose veins. They won't make the veins go away but they will probably help to keep them from getting worse. Avoid standing for long periods of time and put your feet up as often as possible. Exercise and keeping a healthy weight never hurts. Bioflavonoids can help swelling.
Bioflavonoids &herbs. I don't know of any medicines that will reverse varicose veins but a variety of bioflavonoids & herbs can strengthen veins & prevent them from worsening. Avoiding prolonged sitting & standing helps & any yoga where your raise your legs will help. See http://altmedicine.About.Com/od/healthconditionsdisease/a/varicose_veins.Htm and http://www.Thorne.Com/altmedrev/.Fulltext/9/3/308.Pdf & my comment:.
None that works. Varicose veins are due to leaking valves in the saphenous vein system. There is a strong hereditary component. There are many potential home remedies such as horse chestnut, witch hazel and certain kinds of berries but none of these work. If you have varicose veins, then you should see a vein specialist for a f/u venous evaluation including a venous ultrasound.
None that I am aware. Varicose veins are due to incompetent valves in the veins themselves. A column of blood pushes back against the valve and if it is "incompetent" and cannot hold the load, then those large bulging veins "pop out". It is not amenable to meds. Pressure support stockings or surgery is usually the cure. Surgery can be removal or certain radiotherapy treatments to ablate them.
Stockings. Wear compression stockings. Ted hose are available in many colors and you can buy them over the counter. They look like leggings. This keeps the veins rom getting larger, or more o them showing up. Also, get out and exercise! yoga is great, so is walking or swimming.