WILLIAM SHUN TZENG MD
Prescription History 1649809385
Internal Medicine in Hacienda Heights, CA
What does Dr. Tzeng prescribe?
In 2024, Dr. Tzeng wrote 943 Medicare prescriptions for 42 medications. The most prescribed was Atorvastatin Calcium, with 112 prescriptions for 58 patients.
Medicare Part D only. These are prescriptions filled by people with Medicare drug coverage in 2024, from the CMS data released in 2026, the most recent year available. CMS does not publish medications with fewer than 11 prescriptions, so this is not a full list of what Dr. Tzeng prescribes.
Medications 42 medications
Prescriptions filled under Medicare Part D in 2024. Select a medication to see what it is used for and how it compares with other California prescribers.
What it is used for
Atorvastatin 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.
Compared with California prescribers
Dr. Tzeng wrote 112 prescriptions for Atorvastatin Calcium, about half as often as the typical California prescriber of it (202). Medicare paid $13.36 per fill, versus $10.47 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Amlodipine is used with or without other medications to treat high blood pressure.
Compared with California prescribers
Dr. Tzeng wrote 78 prescriptions for Amlodipine Besylate, about half as often as the typical California prescriber of it (141). Medicare paid $7.24 per fill, versus $7.08 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Levothyroxine is used to treat an underactive thyroid (hypothyroidism).
Compared with California prescribers
Dr. Tzeng wrote 48 prescriptions for Levothyroxine Sodium, about 38% as often as the typical California prescriber of it (125). Medicare paid $10.19 per fill, versus $13.30 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Metformin is used with a proper diet and exercise program and possibly with other medications to control high blood sugar.
Compared with California prescribers
Dr. Tzeng wrote 47 prescriptions for Metformin Hcl Er, about 86% as often as the typical California prescriber of it (55). Medicare paid $8.95 per fill, versus $9.99 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Losartan is used to treat high blood pressure (hypertension) and to help protect the kidneys from damage due to diabetes.
Compared with California prescribers
Dr. Tzeng wrote 41 prescriptions for Losartan Potassium, about 34% as often as the typical California prescriber of it (121). Medicare paid $11.03 per fill, versus $10.35 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Tamsulosin is used by men to treat the symptoms of an enlarged prostate (benign prostatic hyperplasia-BPH).
Compared with California prescribers
Dr. Tzeng wrote 39 prescriptions for Tamsulosin Hcl, about half as often as the typical California prescriber of it (84). Medicare paid $17.19 per fill, versus $15.02 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Levocetirizine is an antihistamine used to relieve allergy symptoms such as watery eyes, runny nose, itching eyes/nose, and sneezing.
Compared with California prescribers
Dr. Tzeng wrote 38 prescriptions for Levocetirizine Dihydrochloride, about 70% as often as the typical California prescriber of it (54). Medicare paid $14.00 per fill, versus $10.77 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Icosapent ethyl is used along with certain other cholesterol medications ("statins" such as atorvastatin, simvastatin) to reduce the risk of heart attack, stroke, and certain types of heart problems that require treatment in a hospital.
Compared with California prescribers
Dr. Tzeng wrote 31 prescriptions for Vascepa, about 38% as often as the typical California prescriber of it (81). Medicare paid $515.58 per fill, versus $410.11 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Dapagliflozin is used with a proper diet and exercise program to control high blood sugar in people with type 2 diabetes.
Compared with California prescribers
Dr. Tzeng wrote 28 prescriptions for Farxiga, about half as often as the typical California prescriber of it (52). Medicare paid $767.24 per fill, versus $914.82 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
This medication is used to treat a variety of skin conditions (such as eczema, dermatitis, allergies, rash).
Compared with California prescribers
Dr. Tzeng wrote 24 prescriptions for Triamcinolone Acetonide, about half as often as the typical California prescriber of it (43). Medicare paid $7.20 per fill, versus $10.03 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Omeprazole is used to treat certain stomach and esophagus problems (such as acid reflux, ulcers).
Compared with California prescribers
Dr. Tzeng wrote 23 prescriptions for Omeprazole, about 29% as often as the typical California prescriber of it (78). Medicare paid $13.37 per fill, versus $11.26 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Fluticasone is used to relieve seasonal and year-round allergic and non-allergic nasal symptoms, such as stuffy/runny nose, itching, and sneezing.
Compared with California prescribers
Dr. Tzeng wrote 21 prescriptions for Fluticasone Propionate, about 42% as often as the typical California prescriber of it (50). Medicare paid $8.55 per fill, versus $15.10 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
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.
Compared with California prescribers
Dr. Tzeng wrote 19 prescriptions for Rosuvastatin Calcium, about 19% as often as the typical California prescriber of it (101). Medicare paid $20.68 per fill, versus $15.64 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
This product is used to treat certain types of heart failure.
Compared with California prescribers
Dr. Tzeng wrote 18 prescriptions for Entresto, about 32% as often as the typical California prescriber of it (57). Medicare paid $734.10 per fill, versus $1,043.51 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Metformin is used with a proper diet and exercise program and possibly with other medications to control high blood sugar.
Compared with California prescribers
Dr. Tzeng wrote 18 prescriptions for Metformin Hcl, about 18% as often as the typical California prescriber of it (100). Medicare paid $11.97 per fill, versus $9.26 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Zolpidem is used for a short time to treat a certain sleep problem (insomnia) in adults.
Compared with California prescribers
Dr. Tzeng wrote 18 prescriptions for Zolpidem Tartrate, about 40% as often as the typical California prescriber of it (45). Medicare paid $3.24 per fill, versus $6.02 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Donepezil is used to treat confusion (dementia) related to Alzheimer's disease.
Compared with California prescribers
Dr. Tzeng wrote 15 prescriptions for Donepezil Hcl, about 26% as often as the typical California prescriber of it (58). Medicare paid $13.08 per fill, versus $12.53 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Gabapentin is used with other medications to prevent and control seizures.
Compared with California prescribers
Dr. Tzeng wrote 15 prescriptions for Gabapentin, about 19% as often as the typical California prescriber of it (80). Medicare paid $7.18 per fill, versus $15.63 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Lisinopril is used to treat high blood pressure.
Compared with California prescribers
Dr. Tzeng wrote 15 prescriptions for Lisinopril, about 15% as often as the typical California prescriber of it (98). Medicare paid $11.93 per fill, versus $8.30 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
This medication is used to treat anxiety.
Compared with California prescribers
Dr. Tzeng wrote 15 prescriptions for Lorazepam, about 35% as often as the typical California prescriber of it (43). Medicare paid $1.40 per fill, versus $6.52 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Tirzepatide is used with a proper diet and exercise program to control high blood sugar in people with type 2 diabetes.
Compared with California prescribers
Dr. Tzeng wrote 15 prescriptions for Mounjaro, about 34% as often as the typical California prescriber of it (45). Medicare paid $1,187.44 per fill, versus $1,191.18 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Alendronate is used to prevent and treat certain types of bone loss (osteoporosis) in adults.
Compared with California prescribers
Dr. Tzeng wrote 14 prescriptions for Alendronate Sodium, about 23% as often as the typical California prescriber of it (61). Medicare paid $3.92 per fill, versus $9.65 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Ezetimibe is used along with a low cholesterol/low fat diet and exercise to help lower cholesterol in the blood.
Compared with California prescribers
Dr. Tzeng wrote 14 prescriptions for Ezetimibe, about 27% as often as the typical California prescriber of it (51). Medicare paid $19.63 per fill, versus $26.00 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Hydralazine is used with or without other medications to treat high blood pressure.
Compared with California prescribers
Dr. Tzeng wrote 14 prescriptions for Hydralazine Hcl, about 32% as often as the typical California prescriber of it (43). Medicare paid $8.05 per fill, versus $14.35 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
This drug is used to treat high blood pressure.
Compared with California prescribers
Dr. Tzeng wrote 14 prescriptions for Losartan-Hydrochlorothiazide, about 36% as often as the typical California prescriber of it (39). Medicare paid $23.39 per fill, versus $13.09 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
This medication is a beta-blocker used to treat chest pain (angina), heart failure, and high blood pressure.
Compared with California prescribers
Dr. Tzeng wrote 14 prescriptions for Metoprolol Succinate, about 16% as often as the typical California prescriber of it (86). Medicare paid $6.96 per fill, versus $14.23 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Insulin aspart protamine/insulin aspart is used along with a proper diet and exercise program to control high blood sugar in people with diabetes.
Compared with California prescribers
Dr. Tzeng wrote 14 prescriptions for Novolog Mix 70-30 Flexpen, about 62% as often as the typical California prescriber of it (23). Medicare paid $133.83 per fill, versus $220.69 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
This drug is used to treat high blood pressure (hypertension).
Compared with California prescribers
Dr. Tzeng wrote 14 prescriptions for Olmesartan-Hydrochlorothiazide, about 35% as often as the typical California prescriber of it (40). Medicare paid $16.99 per fill, versus $31.37 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Allopurinol is used to treat gout and certain types of kidney stones.
Compared with California prescribers
Dr. Tzeng wrote 13 prescriptions for Allopurinol, about 29% as often as the typical California prescriber of it (44). Medicare paid $18.69 per fill, versus $10.39 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Isosorbide mononitrate is used to prevent chest pain (angina) in patients with a certain heart condition (coronary artery disease).
Compared with California prescribers
Dr. Tzeng wrote 13 prescriptions for Isosorbide Mononitrate Er, about 37% as often as the typical California prescriber of it (35). Medicare paid $5.77 per fill, versus $14.01 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
This combination medication is used with a proper diet and exercise program and possibly with other medications to control high blood sugar.
Compared with California prescribers
Dr. Tzeng wrote 13 prescriptions for Janumet, about 37% as often as the typical California prescriber of it (35). Medicare paid $857.99 per fill, versus $763.33 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Empagliflozin is used with a proper diet and exercise program to control high blood sugar in people with type 2 diabetes.
Compared with California prescribers
Dr. Tzeng wrote 13 prescriptions for Jardiance, about 23% as often as the typical California prescriber of it (58). Medicare paid $1,486.89 per fill, versus $933.82 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Clopidogrel is used to prevent heart attacks and strokes in persons with heart disease (recent heart attack), recent stroke, or blood circulation disease (peripheral vascular disease).
Compared with California prescribers
Dr. Tzeng wrote 12 prescriptions for Clopidogrel, about 25% as often as the typical California prescriber of it (48). Medicare paid $1.72 per fill, versus $12.42 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Finasteride is used to shrink an enlarged prostate (benign prostatic hyperplasia or BPH) in adult men.
Compared with California prescribers
Dr. Tzeng wrote 12 prescriptions for Finasteride, about 21% as often as the typical California prescriber of it (56). Medicare paid $15.60 per fill, versus $13.71 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Ibuprofen is used to relieve pain from various conditions such as headache, dental pain, menstrual cramps, muscle aches, or arthritis.
Compared with California prescribers
Dr. Tzeng wrote 12 prescriptions for Ibuprofen, about 29% as often as the typical California prescriber of it (42). Medicare paid $3.24 per fill, versus $6.71 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
This is a long-acting form of oxybutynin that is used to treat overactive bladder and urinary conditions.
Compared with California prescribers
Dr. Tzeng wrote 12 prescriptions for Oxybutynin Chloride Er, about 40% as often as the typical California prescriber of it (30). Medicare paid $4.69 per fill, versus $23.09 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Pantoprazole is used to treat certain stomach and esophagus problems (such as acid reflux).
Compared with California prescribers
Dr. Tzeng wrote 12 prescriptions for Pantoprazole Sodium, about 19% as often as the typical California prescriber of it (65). Medicare paid $6.70 per fill, versus $13.87 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Carvedilol is used to treat high blood pressure and heart failure.
Compared with California prescribers
Dr. Tzeng wrote 11 prescriptions for Carvedilol, about 19% as often as the typical California prescriber of it (56). Medicare paid $3.52 per fill, versus $8.98 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Memantine is used to treat moderate to severe confusion (dementia) related to Alzheimer's disease.
Compared with California prescribers
Dr. Tzeng wrote 11 prescriptions for Memantine Hcl, about 20% as often as the typical California prescriber of it (56). Medicare paid $33.29 per fill, versus $29.89 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Olmesartan is used to treat high blood pressure (hypertension).
Compared with California prescribers
Dr. Tzeng wrote 11 prescriptions for Olmesartan Medoxomil, about 23% as often as the typical California prescriber of it (48). Medicare paid $18.18 per fill, versus $18.88 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
What it is used for
Semaglutide is used with a proper diet and exercise program to control high blood sugar in people with type 2 diabetes.
Compared with California prescribers
Dr. Tzeng wrote 11 prescriptions for Ozempic, about 20% as often as the typical California prescriber of it (56). Medicare paid $1,184.83 per fill, versus $1,102.15 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
Compared with California prescribers
Dr. Tzeng wrote 11 prescriptions for Single Use Swab, about 38% as often as the typical California prescriber of it (29). Medicare paid $1.88 per fill, versus $2.63 statewide.
Volume reflects how many Medicare patients a practice sees as well as prescribing habits. It is not a measure of quality.
Questions about Dr. Tzeng’s prescriptions
What does Dr. Tzeng prescribe most?
In 2024 Medicare Part D data, Dr. Tzeng's most prescribed medications were Atorvastatin Calcium (112), Amlodipine Besylate (78) and Levothyroxine Sodium (48).
How does Dr. Tzeng's prescribing compare with other California prescribers?
Of the 42 medications with a state comparison, Dr. Tzeng prescribes 1 about as often than the typical California prescriber and 41 less often. Volume reflects practice size as well as prescribing habits.
Does this list show every medication Dr. Tzeng prescribes?
No. It covers prescriptions filled by people with Medicare Part D drug coverage in 2024, and CMS leaves out any medication with fewer than 11 prescriptions.
About this data
This page shows one provider’s slice of public Medicare files. NPI Profile does not receive prescriptions or patient records.
| Source | What it provides here | Data year |
|---|---|---|
| CMS Medicare Part D Prescribers by Provider and Drug | Each medication, prescriptions, patients, 30-day fills, days of medication and cost. State comparisons average the California prescribers of the same medication and form, where at least five wrote it. | 2024 (released 2026, the most recent available) |
| CMS Medicare Part D Drug Spending Dashboard | What each medication is used for. | 2024 |
- Only prescriptions filled by people with Medicare Part D drug coverage are counted. Private insurance, Medicaid and cash purchases are not.
- CMS leaves out medications with fewer than 11 prescriptions and hides patient counts under 11.
- Cost per fill is what the plan and the patient paid the pharmacy together, not what you pay at the counter.
- Medication descriptions are summaries from CMS. They are not medical advice; ask a health care professional about any medication.
