The pills are light sensitive and need to stay in the shaded bottle that the patient will get them in.
The pills have a relatively short life (check the PDR) and the patient should refill the prescription in the recommended time, or they will loose their potency. If the patient uses a pill, and he does not have a slight burning sensation under his tongue, the pills are probably no longer effective.
The pills or paste can cause headaches, and seems to be a frequent side effect.
Use only the amount prescribed. Too much paste or too many pills can cause the blood pressure to fall (vasodilation). The patient should be aware of dizziness or light headedness from this side effect, and if it persists he needs to call his MD.
Be sure and tell the patient (if he is using the paste) to remove the old paste before applying a new dose.
If he is using the pills on an as needed basis for chest pain, the usual instructions are to use three pills, five minutes apart for pain relief. If he has no relief, he needs to call his MD or go to the ER. How to use the pills will be determined by his MD.
There are probably more instructions needed, but that's all I can think of now.