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.
Prescribing Schedule 4 medicines (S4s) S4 prescriptions are valid for 12 months. An S4 prescription is valid if the following information is provided: name and address of the prescriber. name and address of the patient. name, form, strength and quantity of the medicine. directions for use, if necessary.