Medical Surgical Labs Top 5 Toxic Drug Levels #5

Question

Which client should phenytoin be used with extreme caution?

Answers

  1. A client with alcoholism.
    • Rationale:

      This answer is correct because chronic alcohol abuse destroys the liver. Phenytoin is primarily metabolized through the liver. The client with liver damage will be at higher risk for phenytoin toxicity. Acute alcohol use increases phenytoin levels, while chronic abuse may decrease phenytoin effectiveness, making it more likely for the client to have a seizure.

  2. A client with diabetes.
    • Rationale:

      This answer is not correct because although phenytoin can raise blood sugar, it does not have to be used with extreme caution. Many clients with diabetes take phenytoin and monitor their blood glucose closely.

  3. A client with osteoporosis.
    • Rationale:

      This answer is not correct because although phenytoin, if used long-term, can lead to decreased bone mass, it does not have to be used with extreme caution in clients with osteoporosis. A vitamin D and calcium supplement is a positive way to combat the decreased bone mass that accompanies phenytoin use.

  4. A client with depression.
    • Rationale:

      This answer is not correct because phenytoin does not have to be used with extreme caution for the client who is depressed unless the client is being treated with a selective serotonin reuptake inhibitor. Using phenytoin together with an SSRI may alter the blood levels and effects of both drugs, and increase the effects of phenytoin.

Overview

Phenytoin is an anticonvulsant with a narrow therapeutic range of 10 – 20 mcg/mL. It is metabolized primarily through the liver and for this reason, clients with liver problems are at higher risk for phenytoin toxicity.

Explanation

Learning Outcomes

Phenytoin is an anticonvulsant with a narrow therapeutic range of 10 – 20 mcg/mL. It is metabolized primarily through the liver and for this reason, clients with liver problems are at higher risk for phenytoin toxicity. Acute alcohol use increases phenytoin levels, while chronic abuse may decrease phenytoin effectiveness, making it more likely for the client to have a seizure. Phenytoin raises blood glucose. Long term use of phenytoin has been found to cause bone weakening. It causes changes in calcium and bone metabolism and has a direct effect on bone cells. Using phenytoin together with an SSRI may alter the blood levels and effects of both drugs, and increase the effects of phenytoin.

Test Taking Tip

To remember the therapeutic range, remember DILANTIN (phenytoin) think of the face of a clock and DIAL-AT-TEN: 10-20 mcg/mL.

Video Rationale