William Rietkerk, MD
Dermatology · Thousand Oaks, CANPI 1720311400
Payments from drug & device makers
Across 270 payments — averaging $35.64 each. Meals, travel, consulting and speaking fees, gifts and royalties reported by drug and device makers.
- UCB, Inc.$2K
- Regeneron Healthcare Solutions, Inc.$1K
- Sanofi$925
- Galderma Laboratories, L.p.$912
- Sun Pharmaceutical Industries Inc.$871
- AbbVie$647
- plus $3K from 24 others
What the payments were for
- Consulting fees$1,95020%
- Food & beverage$7,28876%
- Education$3854%
Most of this is food and beverage — typically meals provided during product presentations at a clinic or hospital. Nationally that is the single largest category of reported payments by count.
General payments by program year
Who reported the general payments
Companies are grouped under their corporate parent — a single manufacturer often files under several CMS reporting entities. Research and ownership payments are counted separately and are not in this table.
| Company | Payments | Total |
|---|---|---|
| UCB, Inc. | 11 | $2,303 |
| Regeneron Healthcare Solutions, Inc. | 25 | $1,026 |
| Sanofi | 32 | $925 |
| Galderma Laboratories, L.p. | 18 | $912 |
| Sun Pharmaceutical Industries Inc. | 30 | $871 |
| AbbVie | 29 | $647 |
| Johnson & Johnson | 21 | $644 |
| Amgen | 18 | $380 |
| LEO Pharma Inc. | 18 | $373 |
| Pfizer | 15 | $310 |
| Lilly USA, LLC | 10 | $282 |
| Incyte Corporation | 6 | $151 |
| Mayne Pharma Commercial LLC | 10 | $120 |
| Ortho Dermatologics, A Division Of Bausch Health US, LLC | 2 | $114 |
| Novartis | 5 | $114 |
| Arcutis Biotherapeutics, Inc. | 5 | $100 |
| Journey Medical Corporation | 1 | $67 |
| Boehringer Ingelheim | 2 | $44 |
| Merz North America, Inc. | 1 | $29 |
| Organon | 1 | $24 |
| Almirall LLC | 1 | $23 |
| Verrica Pharmaceuticals Inc. | 1 | $23 |
| VYNE Pharmaceuticals Inc. | 1 | $22 |
| Organogenesis Inc. | 1 | $22 |
| E.r. Squibb & Sons, L.L.C. | 1 | $21 |
| Biofrontera Inc. | 1 | $18 |
| Cipher Pharmaceuticals US LLC | 1 | $16 |
| LNHC, Inc | 1 | $14 |
| Botanix SB Inc | 1 | $14 |
| EPI Health, LLC | 1 | $12 |
What the payments were tied to
Products named in the reported payments. Only payments of $100 or more are attributed here — the typical reported payment nationally is a meal worth about $16, and listing those product-by-product would be noise.
How this compares
$9,623 in reported general payments places this provider in the 75th percentile of 1,875 dermatology providers in California.
Medicare billing
What this is not: this is the amount Original Medicare Part B allowed for services this provider billed in 2024. It is not their income. It excludes Medicare Advantage — now more than half of all Medicare enrollment — along with Medicaid and all commercial insurance, and it is gross practice revenue before staff, rent, supplies and malpractice premiums. CMS also suppresses any figure covering ten or fewer patients, so low-volume providers appear smaller than they are.
Most prescribed under Part D
| Drug | Claims | Cost to plans & patients |
|---|---|---|
| Betamethasone Dipropionate | 197 | $6,533 |
| Clobetasol Propionate | 84 | $4,995 |
| Fluorouracil | 70 | $4,679 |
| Ketoconazole | 170 | $3,183 |
| ValacyclovirValacyclovir Hcl | 45 | $2,983 |
| CiclopiroxCiclopirox Olamine | 165 | $2,674 |
| Metronidazole | 49 | $2,349 |
| Betamethasone Diprop AugmentedBetamethasone/Propylene Glyc | 42 | $1,488 |
| Triamcinolone Acetonide | 160 | $1,421 |
| Clotrimazole-BetamethasoneClotrimazole/Betamethasone Dip | 48 | $1,313 |
| Ciclopirox | 22 | $706 |
| Mupirocin | 117 | $683 |
| Clindamycin Phosphate | 18 | $600 |
| Doxycycline Hyclate | 30 | $565 |
| Nystatin | 29 | $467 |
Paid to pharmacies, not to this prescriber.
Other dermatology in Thousand Oaks
- Navid EzraThousand Oaks$7.8M
- Vivian LaquerIrvine$20.9M
- Howard SofenLos Angeles$16.1M
- Raja SivamaniSacramento$11.8M
- Jennifer SoungSanta Ana$10.3M
- Stacy SmithEncinitas$7.9M
- Paul YamauchiSanta Monica$7.8M
- Paul WallaceBeverly Hills$7.1M
- April ArmstrongLos Angeles$6.2M
- David RayhanHuntington Beach$5.2M
Where these figures come from
- Payments: CMS Open Payments, program years 2019–2025 (publication P06302026_06032026).
- Billing: Medicare Physician & Other Practitioners, data year 2024. Original Medicare Part B only.
- Identity: NPPES NPI Registry, July 2026.