# A nurse teaches a client newly prescribed phenytoin about oral self-care. Which instruction is most important to prevent a common long-term side effect?

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> language: en  
> subject: Medical Emergencies  
> category: PA

## Question

A nurse teaches a client newly prescribed phenytoin about oral self-care. Which instruction is most important to prevent a common long-term side effect?

## Option

1. Avoid green leafy vegetables to prevent drug interactions
2. Take the medication only with high-fat meals
3. Brush teeth twice daily, floss, and schedule dental cleanings every 3-6 months **✔ Correct answer**
4. Increase fluid intake to dilute the medication

**Correct answer: 3**

## Explanation

Correct (2): Gingival hyperplasia develops in up to 50% of phenytoin users from fibroblast proliferation in gum tissue. Diligent oral hygiene — brushing, flossing, and dental cleanings every 3-6 months — significantly reduces severity. (1) Green leafy vegetable restriction is for warfarin, not phenytoin. (3) Phenytoin can be taken with or without food; high-fat is not required. (4) Hydration does not affect phenytoin level meaningfully.

## In-depth explanation

Memory Tip Phenytoin = "5 Hs" — Hyperplasia (gums), Hirsutism, Hyperglycemia, Hyperkinesia in kids, Hypotension (IV). Patient Teaching Tell the dentist about phenytoin at every visit.

## Clinical scenario

Scenario 22-year-old college student newly diagnosed with generalized tonic-clonic seizures starting phenytoin 300 mg PO daily. Receiving outpatient teaching.

## Key concepts

- **Gingival hyperplasia** — Overgrowth of gum tissue; common phenytoin adverse effect mitigated by oral hygiene.
- **Oral hygiene** — Brushing, flossing, and dental visits; preventive measure against phenytoin-induced gingival hyperplasia.
- **Hirsutism** — Excessive hair growth; another cosmetic side effect of phenytoin especially troubling in adolescents.

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