Nathan Visweshwar, MD
Hematology & Oncology · Tampa, FLNPI 1033214325
Payments from drug & device makers
What this record shows
This record is dominated by speaking fees: $5,458 of the $5,570 with a category attached, or 98.0%. CSL Behring accounts for 98.0% of it on its own, with 2 other manufacturers making up the rest. Reporting peaked in 2024 at $3,892 and has fallen 97.6% since, to $94 in 2025.
Across 8 payments — averaging $696.27 each. Meals, travel, consulting and speaking fees, gifts and royalties reported by drug and device makers.
- CSL Behring$5K
- Atricure, Inc.$94
- Philips North America LLC$19
Across 128 payments — averaging $2954.63 each. Payments tied to a research study. These frequently flow through the physician to a hospital or research institution rather than to the physician personally.
- Pfizer$258K
- Sobi, Inc$65K
- CSL Behring$55K
What the payments were for
- Speaking & faculty fees$5,45898%
- Food & beverage$1132%
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 |
|---|---|---|
| CSL Behring | 6 | $5,458 |
| Atricure, Inc. | 1 | $94 |
| Philips North America LLC | 1 | $19 |
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.
- HEMGENIX$5,369
How this compares
$5,570 in reported general payments places this provider in the 55th percentile of 694 hematology & oncology providers in Florida.
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 |
|---|---|---|
| UltomirisRavulizumab-Cwvz | 11 | $727,980 |
| PromactaEltrombopag Olamine | 12 | $44,346 |
| EliquisApixaban | 36 | $34,012 |
| XareltoRivaroxaban | 23 | $26,870 |
| Enoxaparin Sodium | 42 | $19,391 |
| Hydroxyurea | 29 | $1,114 |
| Prednisone | 21 | $104 |
Paid to pharmacies, not to this prescriber.
Other hematology & oncology in Tampa
- Damian LaberTampa$753K
- Richard KimTampa$637K
- Ariel Grajales CruzTampa$625K
- Julio ChavezTampa$383K
- David SallmanTampa$285K
- Daniel Kerr IiTampa$193K
- Bijal ShahTampa$150K
- Nikesh ShahTampa$141K
- Kendra SweetTampa$139K
- Hayder SaeedTampa$127K
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.