Thank you for your question. You are correct in saying that the Caverject patient information instructs you to inject at a 90 degree angle, while the Edex patient information instructs you to inject the needle horizontally. Although the directions are worded differently, if you refer to the pictures in the patient information, the injection technique is the same for both. The needle should be inserted into the corpos cavernosum (the spongy tissue) that is located on the left and right sides of the penis. The needle should be inserted at a right angle (90 degrees) to the shaft of the penis, but still even (horizontal) with the penis - that is, the needle should not be injected from above or below the penis.
I hope this helps. If you would like to read more about Caverject and Edex, you can find information here.
Best of luck,