What is drug tolerance?
Drug tolerance is when your body, over time, gets used to the effects of a drug. As this happens, you may need to take a higher dose of the drug to get the same effect. For example, people who take an opioid for a long period of time often need a higher dose of the drug in order to get the same pain relief.
If you stop using an opioid for a period of time, your tolerance will begin to fade. Resuming the medication at the same higher dose when your tolerance was increased can be too much for the body to take. If you stop taking a medication, and then resume, talk to your doctor about dosage.
What is drug dependence?
Drug dependence is when the way your body works changes because you have taken a drug for a long time. These changes cause you to have withdrawal symptoms when you stop using the drug. Withdrawal symptoms can be mild or severe, and may include sweating, nausea or vomiting, chills, diarrhea, shaking, pain, depression, insomnia, and fatigue.
If you have been taking a prescription opioid for a long time, your doctor can help you avoid withdrawal symptoms by gradually lowering your dose over time until you no longer need the medicine.
What is the difference between drug tolerance, dependence, and addiction?
Drug tolerance and dependence are a normal part of taking any opioid drug for a long time. You can be tolerant to, or dependent on, a drug and not yet be addicted to it.
Addiction, however, is not normal. It is a disease. You are addicted to a drug when it seems that neither your body nor your mind can function without the drug. Addiction causes you to obsessively seek out the drug, even when the drug use causes behavior, health, or relationship problems.
How do I know if I'm addicted?
You might be addicted if you crave the drug or if you feel like you can’t control the urge to take the drug. You may also be addicted if you keep using the drug without your doctor’s consent, even if the drug is causing trouble for you. The trouble may be with your health, with money, with work or school, with the law, or with your relationships with family or friends. Your friends and family may be aware of your addiction problem before you are, because they notice the changes in your behavior.
See a list of resources used in the development of this information.
Written by familydoctor.org editorial staff