Email Certain side effects, whether serious or less threatening, often display if you or a loved one accidentally took too much morphine. The following are some signs of a morphine overdose. If you or a loved one are taking morphine as a pain medication, it’s essential to remember that morphine is a strong opioid that may cause an overdose if taken incorrectly. Following your doctor’s recommended dosage is the first step in taking morphine properly, but it’s also smart to learn the signs of a morphine overdose. How Much Morphine Does It Take to Overdose? Put simply, taking any amount that exceeds your doctor’s prescribed dosage increases the risk of overdose, Jeffrey Zipper, MD, chief medical officer at iRecovery USA in Boca Raton, Florida, tells WebMD Connect to Care. It's also important to note that overdosing on morphine could prove fatal.