Doctor profile · Federal record

Dr. Katherine Willems, FNP

Family Nurse Practitioner · Clearlake, CA

  • NPI 1134393069
  • MIPS 72.1 / 100 · 2023
  • 18 yrs on file
  • Female
  • Group practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
15230 Lakeshore Dr
Clearlake, CA 954228107
(707) 995-4500

Credentials & registration

NPPES · NUCC
NPI registered
April 2008 — 18 yrs on file
Profile last updated
March 4, 2014
Specialty taxonomy
363LF0000X — NUCC code
State license (1)
California #404784-7693

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1134393069. Last verified May 11, 2026.

Open Payments

Industry payments received

CMS Open Payments
All-time total
$18
Transactions
1
Manufacturers
1
Payer (manufacturer) Industry Txns Amount
Indivior INC. 1 $18.18

By nature of payment

Food and Beverage
$18

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
1,435
Patients
481
Total drug cost
$36,621
Drug Type Claims Patients Total cost
Atorvastatin Calcium Generic 209 75 $4,429
Hydrocodone-Acetaminophen (Hydrocodone/Acetaminophen) Brand 141 25 $4,023
Levothyroxine Sodium Generic 138 49 $3,974
Amlodipine Besylate Generic 115 45 $2,005
Losartan Potassium Generic 115 42 $1,968
Lisinopril Generic 102 37 $1,532
Gabapentin Generic 99 35 $3,589
Rosuvastatin Calcium Generic 90 32 $3,222
Metformin Hcl Generic 75 21 $1,313
Omeprazole Generic 70 27 $1,703

Frequently asked questions

Auto-generated from federal data
What is Dr. Katherine Willems's medical specialty?
Dr. Katherine Willems practices Family Nurse Practitioner in Clearlake, CA.
Where does Dr. Katherine Willems practice?
Dr. Katherine Willems practices at 15230 Lakeshore Dr, Clearlake, CA 954228107. Office phone: 7079954500.
What is Dr. Katherine Willems's NPI?
Dr. Katherine Willems's National Provider Identifier (NPI) is 1134393069, issued by NPPES.