What is Drug Toxicity
Drug toxicity refers to harmful and unwanted (adverse) effects of a drug in your body. Drug toxicity often results from taking too much of a drug (overdose) by accident or on purpose.
With some drugs, there is only a small difference between the dose that is needed to treat your condition and a dose that is harmful (narrow therapeutic range). However, any drug can be toxic at high doses, and even normal doses of certain drugs can be toxic for some people. These include over-the-counter (OTC) medicines.
Drug toxicity can happen suddenly when you first start taking a drug or when you suddenly take too much of a drug (acute toxicity). It can also happen as a result of taking a drug for a long period of time (chronic toxicity). The effects of drug toxicity can be mild, dangerous, or even deadly.
What are the causes?
Many things can cause drug toxicity. Common causes of acute toxicity include a drug overdose or an allergic reaction to a drug.
Most drugs are broken down (metabolized) by your liver and eliminated (excreted) by your kidneys. Chronic drug toxicity can result from changes in the way that your body metabolizes a drug. This can happen, for example, if you weigh less than you did when you started taking a drug but you keep taking the same dose that you took at the heavier weight.
What increases the risk?
You may have a higher risk for drug toxicity if you:
- Are under 18 years of age or over 65 years of age.
- Have liver disease, kidney disease, or another medical condition.
- Are taking more than one drug.
- Are pregnant.
- Are allergic to certain drugs.
- Have genes that cause you to be more affected by (susceptible to) certain drugs.
- Take a drug that has a narrow therapeutic range.
Certain types of drugs are more likely than others to cause toxicity. Many drugs have a narrow therapeutic range, including:
- Blood thinners.
- Heart medicines.
- Diabetes medicines.
- Medicines to prevent or stop seizures.
- Theophylline for asthma.
- Lithium for bipolar disorder.
What are the signs or symptoms?
Signs and symptoms of drug toxicity depend on the drug and the amount that was taken. They may start suddenly or develop gradually over time.
How is this diagnosed?
Drug toxicity may be diagnosed based on your symptoms. Some drugs have known side effects that suggest toxicity. It is important that you tell health care provider about all of the drugs that you are taking and whether you have ever had a reaction to a drug.
Your health care provider will do a physical exam. You may have tests to check for drug toxicity, including:
- Blood tests to measure the amount of the drug in your blood or to check for signs of kidney or liver damage.
- Urine tests.
- Other tests to check for organ damage.
How is this treated?
Treatment may include:
- Stopping the drug.
- Lowering the dose of the drug.
- Switching to a different drug.
You may also need treatment to stop or reverse the effects of the toxicity. These treatments depend on the drug that caused the toxicity, how severe the toxicity is, and which parts of your body are affected.
Follow these instructions at home:
- Take medicines only as directed by your health care provider. Always ask your health care provider to discuss the possible side effects of any new drug that you start taking.
- Keep a list of all of the drugs that you take, including over-the-counter medicines. Bring this list with you to all of your medical visits.
- Read the drug inserts that come with your medicines.
- Keep all follow-up visits as directed by your health care provider. This is important.
Contact a health care provider if:
- Your symptoms return.
- You develop any new signs or symptoms when you are taking medicines.
- You notice any signs that indicate that you are taking too much of your medicine, based on what your health care provider told you to watch for.
Get help right away if:
- You have chest pain.
- You have difficulty breathing.
- You have a loss of consciousness.
