FRANK CASTILLO JR. NP
Prescription History 1639623770
Nurse Practitioner in Walnut Creek, CA

Active since August 05, 2016PECOS EnrolledAccepts Medicare Assignment
100 N WIGET LN STE 290, WALNUT CREEK, CA 94598(925) 937-7740 Get Directions

NPPES record last updated: September 22, 2025. Verified against the NPPES registry weekly; last sync: October 04, 2026.

Medicare Part D Prescription History

Explore the verified Medicare Part D prescription history, volume metrics, and calculated drug costs for FRANK CASTILLO JR. NP, an active Nurse Practitioner specialist practicing in Walnut Creek, CA. Our medical registry currently tracks 2 unique pharmaceutical formulations prescribed by this provider, representing an estimated volume of 22 documented patient claims. Among these therapy options, the most frequently utilized medication is Acyclovir, which accounts for 11 claims alone. Use the table below to sort by claims, cost, or utilization compared with the state average; select any medication for its full profile.

2
Medications
22
Total Claims
28
30-Day Fills
Acyclovir
Most Prescribed · 11 claims
View details
2 medications · 2023 Medicare Part D
Medicare Part D medications prescribed by FRANK CASTILLO JR. NP in 2023, with prescription volumes, average cost per fill, and CA state comparisons
Medication Prescriptions (2023)Rx (2023) Avg Cost per FillCost / Fill Vs. Other CA PrescribersVs. CA Avg
Acyclovir11$9.40▼ below CA avg▼ Less than typical

About Acyclovir: Acyclovir is used to treat infections caused by certain types of viruses. Show more ▾

It treats cold sores around the mouth (caused by herpes simplex), shingles (caused by herpes zoster), and chickenpox. This medication is also used to treat outbreaks of genital herpes. In people with frequent outbreaks, acyclovir is used to help reduce the number of future episodes. Acyclovir is an antiviral drug. However, it is not a cure for these infections. The viruses that cause these infections continue to live in the body even between outbreaks. Acyclovir decreases the severity and length of these outbreaks. It helps the sores heal faster, keeps new sores from forming, and decreases pain/itching. This medication may also help reduce how long pain remains after the sores heal. In addition, in people with a weakened immune system, acyclovir can decrease the risk of the virus spreading to other parts of the body and causing serious infections. A GUANOSINE analog that acts as an antimetabolite. Viruses are especially susceptible. Used especially against herpes.

In 2023, this provider wrote 11 Medicare prescriptions for Acyclovir, about half the volume of the typical California prescriber of this medication (24). Medicare paid an average of $9.40 per fill, versus $26.52 statewide.

How often this provider prescribes it

This provider
11
CA average
24.0

This provider prescribes this medication less often than the average CA prescriber. Utilization reflects practice size as well as clinical preference.

What Medicare paid per fill

This provider
$9.40
CA average
$26.52

This provider's average cost per fill is below the CA average for this medication.

11
30-Day Fills
standardized to 30-day supplies
330
Days of Medication
total across all patients in 2023
Rosuvastatin Calcium11$9.93▼ below CA avg▼ Less than typical

About Rosuvastatin Calcium: Rosuvastatin is used along with a proper diet to help lower bad cholesterol and fats (such as LDL, triglycerides) and raise good cholesterol (HDL) in the blood. Show more ▾

It belongs to a group of drugs known as statins. It works by reducing the amount of cholesterol made by the liver. Lowering bad cholesterol and triglycerides and raising good cholesterol decreases the risk of heart disease and helps to prevent strokes and heart attacks. In addition to eating a proper diet (such as a low cholesterol/low-fat diet), other lifestyle changes that may help this medication work better include exercising, losing weight if overweight, and stopping smoking. Talk with your doctor for more details. A HYDROXYMETHYLGLUTARYL-COA-REDUCTASE INHIBITOR, or statin, that reduces the plasma concentrations of LDL-CHOLESTEROL; APOLIPOPROTEIN B, and TRIGLYCERIDES while increasing HDL-CHOLESTEROL levels in patients with HYPERCHOLESTEROLEMIA and those at risk for CARDIOVASCULAR DISEASES.

In 2023, this provider wrote 11 Medicare prescriptions for Rosuvastatin Calcium, about 13% of the volume of the typical California prescriber of this medication (86). Medicare paid an average of $9.93 per fill, versus $35.52 statewide.

How often this provider prescribes it

This provider
11
CA average
86.0

This provider prescribes this medication less often than the average CA prescriber. Utilization reflects practice size as well as clinical preference.

What Medicare paid per fill

This provider
$9.93
CA average
$35.52

This provider's average cost per fill is below the CA average for this medication.

17
30-Day Fills
standardized to 30-day supplies
510
Days of Medication
total across all patients in 2023
No medications match the current filters.
▲ More than typical≈ Typical▼ Less than typical= prescription volume vs the average CA prescriber of the same medication; volume reflects practice size as well as clinical preference.Green cost= below the CA average cost per fill.

About this data. The prescription history for FRANK CASTILLO JR. NP is compiled from the Centers for Medicare & Medicaid Services (CMS) Medicare Part D Prescriber Public Use File for calendar year 2023, the most recent federal release. Figures cover prescriptions filled for Medicare Part D beneficiaries only; prescriptions under private insurance, Medicaid, or self-pay plans are not included. Because prescribing decisions are generally consistent across coverage types, this record offers a useful view of the overall Nurse Practitioner prescribing approach at this Walnut Creek, CA practice.

Reading the costs. Drug costs are gross amounts paid to pharmacies under Part D, including both plan and beneficiary payments. They are not the price a patient pays at the pharmacy counter. Medications with fewer than 11 claims are excluded from the federal source data, and state comparisons use the average volume among CA prescribers of the same medication. Always confirm current medications and costs directly with the provider and your plan.