Internal Medicine, Infectious Disease · San Antonio, TX
NPI
1013907963
Since 2005
Specialty
Internal Medicine, Infectious Disease
Code 207RI0200X
Group practices
1
Medicare group memberships
Hospitals
5
Hospital affiliations
150 E Sonterra Blvd, Suite 170
San Antonio, TX, 78258
Phone (210) 481-2800
Groups this clinician bills Medicare through
Medicare paid, 2024
$265K
4,800 services
Medicare patients, 2024
450
Average age 74
Drug cost, 2024
$1.7M
2,369 prescriptions
Company payments, 2025
$439
From 7 companies
Procedures and visits billed to Original Medicare, 2024
In 2024, the most common Medicare service billed by Robert A Zajac was code J1561 (injection, immune globulin, (gamunex-c/gammaked), non-lyophilized (e.g., liquid), 500 mg), 2,110 times for 13 patients. In total Robert A Zajac billed 4,800 services in 30 codes, and Medicare paid $265K.
Official US government data: the national provider registry and Medicare enrollment records, linked by NPI. Last update of this record: 2024-08-08.
| Code | Setting | Services | Patients | Paid per service | Medicare paid |
|---|
| J1561 Injection, immune globulin, (gamunex-c/gammaked), non-lyophilized (e.g., liquid), 500 mg | Office | 2,110 | 13 | $38.68 | $82K |
| 99233 Hospital E&M - Subsequent | Facility | 471 | 226 | $89.74 | $42K |
| 99232 Hospital E&M - Subsequent | Facility | 384 | 175 | $58.18 | $22K |
| 99223 Hospital E&M - Initial | Facility | 226 | 224 | $130.01 | $29K |
| 99214 Office E&M - Established | Office | 111 | 78 | $83.15 | $9,230 |
| 96366 Intravenous Infusion, Hydration | Office | 97 | 18 | $14.17 | $1,374 |
| 99215 Office E&M - Established | Office | 60 | 47 | $132.02 | $7,921 |
| G0180 Physician or allowed practitioner certification for medicare-covered home health services under a home health plan of care (patient not present), including contacts with home health agency and review of reports of patient status required by physicians and | Office | 37 | 34 | $40.99 | $1,516 |
| 99222 Hospital E&M - Initial | Facility | 36 | 31 | $95.00 | $3,420 |
| 96365 Intravenous Infusion, Hydration | Office | 32 | 18 | $43.27 | $1,385 |
| 99231 Hospital E&M - Subsequent | Facility | 30 | 25 | $37.83 | $1,135 |
| G0181 Physician or allowed practitioner supervision of a patient receiving medicare-covered services provided by a participating home health agency (patient not present) requiring complex and multidisciplinary care modalities involving regular physician or allow | Office | 16 | 14 | $80.16 | $1,283 |
| 99205 Office E&M - New | Office | 12 | 12 | $155.98 | $1,872 |
By year: 2022 $2.0M for 30,401 services; 2023 $3.2M for 60,885 services; 2024 $265K for 4,800 services.
Medicare prescription drug claims, 2024
In 2024, the drug Robert A Zajac prescribed most often to Medicare patients was Doxycycline Hyclate, with 437 prescriptions and refills. In total Robert A Zajac wrote 2,369 Medicare prescriptions that cost $1.7M.
| Drug | Claims | 30-day fills | Patients | Cost |
|---|---|---|---|---|
| Doxycycline Hyclate Generic | 437 | 591 | 150 | $13K |
| Cefdinir Generic | 162 | 224 | 64 | $7,839 |
| Biktarvy Bictegrav/Emtricit/Tenofov Ala | 147 | 147 | 21 | $583K |
| Cefadroxil Generic | 138 | 204 | 54 | $3,042 |
| Daptomycin Generic | 81 | 81 | 21 | $25K |
| Levofloxacin Generic | 80 | 85 | 50 | $565 |
| Amoxicillin Generic | 58 | 78 | 22 | $352 |
| Memantine Hcl Generic | 56 | 76 | 16 | $1,314 |
| Piperacillin-Tazobactam Piperacillin Sodium/Tazobactam | 54 | 54 | 16 | $7,157 |
| Sulfamethoxazole-Trimethoprim Sulfamethoxazole/Trimethoprim | 52 | 59 | 19 | $620 |
| Genvoya Elviteg/Cob/Emtri/Tenof Alafen | 50 | 50 | Under 11 | $194K |
| Cefepime Hcl Generic | 49 | 49 | 16 | $5,064 |
| Vancomycin Hcl Generic | 48 | 48 | 21 | $3,567 |
| Azithromycin Generic | 45 | 75 | 19 | $1,030 |
| Cefazolin Sodium Generic | 43 | 43 | 11 | $2,388 |
Brand drugs: 442 claims; generic drugs: 1,927 claims.
Money and other things of value reported by the companies
In 2025, drug and medical device companies paid Robert A Zajac $439 ($439 in general payments such as food, travel and fees) from 7 companies. The largest payer was Abbvie Inc. with $163.
Official US government data on Original Medicare services, Medicare prescription drug plans and the payments drug and device companies must report. Services with fewer than 11 patients and drugs with fewer than 11 claims are not published. Procedure codes are shown by number with their public category.