A nurse is collecting a medication history from the parent of a preschooler who comes to the clinic for routine immunizations. For which of the following findings should the nurse withhold the varicella immunization?

A. Drowsiness. Dimenhydrinate is an antihistamine that works by blocking histamine and acetylcholine receptors in the brain to prevent nausea and vomiting. A common adverse effect is drowsiness due to its sedative properties, which can impair alertness and coordination. Clients should be advised to avoid activities requiring mental alertness, such as driving, until they understand how the medication affects them.

B. Hypertension. Dimenhydrinate does not typically cause hypertension. Instead, it may lead to mild hypotension due to its sedative and anticholinergic effects. Clients with pre-existing hypertension should still monitor their blood pressure, but significant increases are uncommon.

C. Polyuria. Increased urination is not associated with dimenhydrinate use. Antihistamines, including dimenhydrinate, have anticholinergic properties, which can lead to urinary retention rather than increased urine output. Clients experiencing difficulty urinating should report this to their healthcare provider.

D. Dependent edema. Dimenhydrinate does not cause fluid retention or edema. Medications that contribute to edema typically involve hormonal, cardiovascular, or kidney-related effects, which are not mechanisms of dimenhydrinate. If a client develops unexplained edema, other underlying conditions should be investigated.

• Client reports having three to four alcoholic beverages a couple times per week. Phenytoin metabolism is significantly affected by alcohol consumption. Chronic alcohol use increases phenytoin clearance, leading to subtherapeutic drug levels and seizure breakthrough. Conversely, acute alcohol intake inhibits phenytoin metabolism, increasing the risk of toxicity. The client should be counseled to avoid alcohol while on phenytoin therapy.
• Client takes diazepam as needed for anxiety. Diazepam is a CNS depressant that interacts with phenytoin, increasing sedation and the risk of respiratory depression. Both medications can cause drowsiness, dizziness, and impaired coordination, raising the risk of falls and injury. The provider should assess whether diazepam should be discontinued or adjusted when initiating phenytoin therapy.
• Last menstrual period was 3 months ago. Phenytoin is Pregnancy Category D, meaning it poses a significant teratogenic risk, including fetal hydantoin syndrome. The missed menstrual period suggests a possible pregnancy, which must be evaluated before starting phenytoin. A pregnancy test should be performed, and alternative antiseizure medications may need to be considered if pregnancy is confirmed.
• Client is a vegetarian and takes a multivitamin daily. Phenytoin interferes with the absorption of folic acid and vitamin D, both of which are crucial for bone health and red blood cell production. Vegetarians are already at higher risk for folate and vitamin B12 deficiency, making supplementation essential. However, multivitamins containing calcium, magnesium, or iron can decrease phenytoin absorption, reducing its effectiveness. The provider should review the multivitamin’s composition and adjust dosing schedules to prevent interactions.
• Temperature 36.4°C (97.6°F), oral. The client’s temperature is within normal range and does not indicate infection or systemic concerns that would affect phenytoin therapy.
• Heart rate 75/min, Respiratory rate 16/min, Blood pressure 100/74 mm Hg, Oxygen saturation 99% on room air.
  All vital signs are stable and do not indicate hemodynamic instability, respiratory depression, or cardiovascular issues that would contraindicate phenytoin administration.
• Skin color is consistent with genetic background. No rashes or lesions. The client has varicose veins. There are no signs of drug hypersensitivity reactions or dermatologic conditions that would require stopping phenytoin therapy.
• S1 S2 auscultated. No murmurs. All peripheral pulses 2+. Lung sounds clear bilaterally.
  There are no cardiopulmonary concerns that would indicate contraindications to phenytoin.
• Abdomen soft, nontender. Normoactive bowel sounds in all 4 quadrants. Last bowel movement was 3 days ago. Voids four to five times a day. Urine is clear, yellow, and odorless. Mild constipation is noted, but this is not a contraindication for phenytoin. The client should be encouraged to increase fiber and fluid intake to prevent worsening constipation, which can sometimes be a side effect of phenytoin.
• Alert and oriented to person, place, and time. Client has full range of motion and is able to maintain flexion against resistance in all four extremities. There are no neurological deficits requiring immediate intervention, and the client's baseline mental status is intact.