1. (General Engineering) tungsten-electrode inert gas welding: a method of welding in which the arc is maintained by a tungsten electrode and shielded from the access of air by an inert gas. Compare MIG welding.
A prescription for a controlled drug is valid for 28 days from the date given on the prescription. usually six months unless it's a controlled i.e. morphine, pethidine and methadone. These medicines are often misused, so have stricter legal controls on their supply to prevent them being obtained illegally. A prescription for a controlled drug is valid for 28 days from the date given on the prescription.
One major change for doctors would be a limit on first-time prescriptions for opioid drugs to a seven-day supply. So for example, a patient who has wisdom tooth surgery or a sports injury could get only seven days worth of opioids without returning to the doctor for another prescription.