RICHARD DERRICK KNOWLES MD
Prescription History 1225113236
Family Medicine in Vancouver, WA
What does Dr. Knowles prescribe?
In 2024, Dr. Knowles wrote 1,666 Medicare prescriptions for 61 medications. The most prescribed was Atorvastatin Calcium, with 100 prescriptions for 35 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. Knowles prescribes.
Medications 61 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 Washington 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 Washington prescribers
Dr. Knowles wrote 100 prescriptions for Atorvastatin Calcium, about 60% as often as the typical Washington prescriber of it (166). Medicare paid $12.74 per fill, versus $11.43 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 Washington prescribers
Dr. Knowles wrote 93 prescriptions for Losartan Potassium, about as often as the typical Washington prescriber of it (102). Medicare paid $9.47 per fill, versus $10.71 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 combination medication is used to relieve moderate to severe pain.
Compared with Washington prescribers
Dr. Knowles wrote 78 prescriptions for Hydrocodone-Acetaminophen, about 1.3 times as often as the typical Washington prescriber of it (60). Medicare paid $21.29 per fill, versus $20.62 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 Washington prescribers
Dr. Knowles wrote 75 prescriptions for Lisinopril, about 72% as often as the typical Washington prescriber of it (105). Medicare paid $5.25 per fill, versus $8.60 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 depression.
Compared with Washington prescribers
Dr. Knowles wrote 50 prescriptions for Trazodone Hcl, about 82% as often as the typical Washington prescriber of it (61). Medicare paid $10.57 per fill, versus $10.78 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 certain mental/mood disorders (such as depression, panic attacks, obsessive compulsive disorder, post-traumatic stress disorder, social anxiety disorder).
Compared with Washington prescribers
Dr. Knowles wrote 48 prescriptions for Sertraline Hcl, about as often as the typical Washington prescriber of it (50). Medicare paid $15.12 per fill, versus $11.19 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 Washington prescribers
Dr. Knowles wrote 47 prescriptions for Levothyroxine Sodium, about 41% as often as the typical Washington prescriber of it (116). Medicare paid $9.04 per fill, versus $11.18 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
Amlodipine is used with or without other medications to treat high blood pressure.
Compared with Washington prescribers
Dr. Knowles wrote 42 prescriptions for Amlodipine Besylate, about 40% as often as the typical Washington prescriber of it (106). Medicare paid $9.45 per fill, versus $7.92 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 Washington prescribers
Dr. Knowles wrote 41 prescriptions for Metformin Hcl Er, about 80% as often as the typical Washington prescriber of it (51). Medicare paid $5.41 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
Gabapentin is used with other medications to prevent and control seizures.
Compared with Washington prescribers
Dr. Knowles wrote 39 prescriptions for Gabapentin, about half as often as the typical Washington prescriber of it (72). Medicare paid $26.20 per fill, versus $19.65 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
This medication is used to help relieve moderate to severe pain.
Compared with Washington prescribers
Dr. Knowles wrote 37 prescriptions for Oxycodone Hcl, about 74% as often as the typical Washington prescriber of it (50). Medicare paid $13.53 per fill, versus $14.22 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 high blood pressure.
Compared with Washington prescribers
Dr. Knowles wrote 36 prescriptions for Hydrochlorothiazide, about 63% as often as the typical Washington prescriber of it (57). Medicare paid $3.38 per fill, versus $5.34 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 depression.
Compared with Washington prescribers
Dr. Knowles wrote 34 prescriptions for Bupropion Xl, about as often as the typical Washington prescriber of it (34). Medicare paid $24.81 per fill, versus $27.11 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
This medication is a beta-blocker used to treat chest pain (angina), heart failure, and high blood pressure.
Compared with Washington prescribers
Dr. Knowles wrote 33 prescriptions for Metoprolol Succinate, about 36% as often as the typical Washington prescriber of it (91). Medicare paid $16.01 per fill, versus $14.75 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 certain mental/mood disorders (such as schizophrenia, bipolar disorder, sudden episodes of mania or depression associated with bipolar disorder).
Compared with Washington prescribers
Dr. Knowles wrote 33 prescriptions for Quetiapine Fumarate, about 67% as often as the typical Washington prescriber of it (49). Medicare paid $15.94 per fill, versus $19.76 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
Albuterol (also known as salbutamol) is used to prevent and treat wheezing and shortness of breath caused by breathing problems (such as asthma, chronic obstructive pulmonary disease).
Compared with Washington prescribers
Dr. Knowles wrote 32 prescriptions for Albuterol Sulfate Hfa, about 63% as often as the typical Washington prescriber of it (51). Medicare paid $34.90 per fill, versus $29.37 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
Furosemide is used to reduce extra fluid in the body (edema) caused by conditions such as heart failure, liver disease, and kidney disease.
Compared with Washington prescribers
Dr. Knowles wrote 32 prescriptions for Furosemide, about half as often as the typical Washington prescriber of it (59). Medicare paid $5.83 per fill, versus $6.29 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 Washington prescribers
Dr. Knowles wrote 31 prescriptions for Ozempic, about 73% as often as the typical Washington prescriber of it (42). Medicare paid $1,240.54 per fill, versus $1,270.49 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 Washington prescribers
Dr. Knowles wrote 28 prescriptions for Metformin Hcl, about half as often as the typical Washington prescriber of it (63). Medicare paid $9.47 per fill, versus $9.63 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
See also Warning section.
Compared with Washington prescribers
Dr. Knowles wrote 27 prescriptions for Acetaminophen-Codeine, about 1.2 times as often as the typical Washington prescriber of it (22). Medicare paid $27.21 per fill, versus $17.06 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 certain mental/mood disorders (such as depression, panic attacks, obsessive compulsive disorder).
Compared with Washington prescribers
Dr. Knowles wrote 26 prescriptions for Fluoxetine Hcl, about 76% as often as the typical Washington prescriber of it (34). Medicare paid $27.49 per fill, versus $12.85 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 Washington prescribers
Dr. Knowles wrote 26 prescriptions for Rosuvastatin Calcium, about 32% as often as the typical Washington prescriber of it (81). Medicare paid $9.42 per fill, versus $14.43 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 certain mental/mood disorders (such as bipolar disorder, schizophrenia, Tourette's syndrome, and irritability associated with autistic disorder).
Compared with Washington prescribers
Dr. Knowles wrote 24 prescriptions for Aripiprazole, about 68% as often as the typical Washington prescriber of it (35). Medicare paid $38.82 per fill, versus $48.17 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 certain mental/mood disorders (such as depression, anxiety).
Compared with Washington prescribers
Dr. Knowles wrote 24 prescriptions for Duloxetine Hcl, about half as often as the typical Washington prescriber of it (44). Medicare paid $27.37 per fill, versus $26.10 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
Simvastatin 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 Washington prescribers
Dr. Knowles wrote 24 prescriptions for Simvastatin, about half as often as the typical Washington prescriber of it (52). Medicare paid $12.43 per fill, versus $9.61 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 Washington prescribers
Dr. Knowles wrote 23 prescriptions for Allopurinol, about half as often as the typical Washington prescriber of it (39). Medicare paid $18.71 per fill, versus $11.44 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 certain bladder problems (overactive bladder, neurogenic detrusor overactivity).
Compared with Washington prescribers
Dr. Knowles wrote 23 prescriptions for Myrbetriq, about 66% as often as the typical Washington prescriber of it (35). Medicare paid $687.50 per fill, versus $679.26 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
This medication is used alone or with other medications to prevent nausea and vomiting caused by cancer drug treatment (chemotherapy) and radiation therapy.
Compared with Washington prescribers
Dr. Knowles wrote 23 prescriptions for Ondansetron Odt, about 88% as often as the typical Washington prescriber of it (26). Medicare paid $15.55 per fill, versus $15.16 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
Apixaban is used to prevent serious blood clots from forming due to a certain irregular heartbeat (atrial fibrillation) or after hip/knee replacement surgery.
Compared with Washington prescribers
Dr. Knowles wrote 22 prescriptions for Eliquis, about 33% as often as the typical Washington prescriber of it (67). Medicare paid $709.72 per fill, versus $994.95 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
Famotidine is used to treat ulcers of the stomach and intestines and to prevent intestinal ulcers from coming back after they have healed.
Compared with Washington prescribers
Dr. Knowles wrote 22 prescriptions for Famotidine, about half as often as the typical Washington prescriber of it (39). Medicare paid $13.88 per fill, versus $16.42 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
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 Washington prescribers
Dr. Knowles wrote 22 prescriptions for Fluticasone Propionate, about 63% as often as the typical Washington prescriber of it (35). Medicare paid $22.31 per fill, versus $18.06 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 Washington prescribers
Dr. Knowles wrote 22 prescriptions for Pantoprazole Sodium, about half as often as the typical Washington prescriber of it (49). Medicare paid $6.88 per fill, versus $14.19 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
Dolutegravir is used with other HIV medications to help control HIV infection.
Compared with Washington prescribers
Dr. Knowles wrote 22 prescriptions for Tivicay, about half as often as the typical Washington prescriber of it (42). Medicare paid $2,247.78 per fill, versus $2,287.95 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 Washington prescribers
Dr. Knowles wrote 21 prescriptions for Zolpidem Tartrate, about 62% as often as the typical Washington prescriber of it (34). Medicare paid $5.25 per fill, versus $7.22 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 Washington prescribers
Dr. Knowles wrote 20 prescriptions for Jardiance, about half as often as the typical Washington prescriber of it (44). Medicare paid $1,365.40 per fill, versus $1,041.39 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
Omeprazole is used to treat certain stomach and esophagus problems (such as acid reflux, ulcers).
Compared with Washington prescribers
Dr. Knowles wrote 19 prescriptions for Omeprazole, about 24% as often as the typical Washington prescriber of it (78). Medicare paid $20.38 per fill, versus $15.28 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
Prednisone is used to treat conditions such as arthritis, blood disorders, breathing problems, severe allergies, skin diseases, cancer, eye problems, and immune system disorders.
Compared with Washington prescribers
Dr. Knowles wrote 19 prescriptions for Prednisone, about half as often as the typical Washington prescriber of it (38). Medicare paid $12.78 per fill, versus $5.30 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
See also Warning section.
Compared with Washington prescribers
Dr. Knowles wrote 19 prescriptions for Tramadol Hcl, about half as often as the typical Washington prescriber of it (40). Medicare paid $3.34 per fill, versus $8.40 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
Glipizide is used with a proper diet and exercise program to control high blood sugar in people with type 2 diabetes.
Compared with Washington prescribers
Dr. Knowles wrote 18 prescriptions for Glipizide Er, about 63% as often as the typical Washington prescriber of it (29). Medicare paid $8.19 per fill, versus $14.57 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
Pravastatin 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 Washington prescribers
Dr. Knowles wrote 18 prescriptions for Pravastatin Sodium, about half as often as the typical Washington prescriber of it (38). Medicare paid $7.22 per fill, versus $14.07 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 certain mental/mood disorders (such as depression, anxiety).
Compared with Washington prescribers
Dr. Knowles wrote 17 prescriptions for Escitalopram Oxalate, about half as often as the typical Washington prescriber of it (37). Medicare paid $11.60 per fill, versus $13.03 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
Ibuprofen is used to relieve pain from various conditions such as headache, dental pain, menstrual cramps, muscle aches, or arthritis.
Compared with Washington prescribers
Dr. Knowles wrote 17 prescriptions for Ibuprofen, about 64% as often as the typical Washington prescriber of it (27). Medicare paid $9.71 per fill, versus $9.00 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
This medication is used to treat muscle spasms caused by certain conditions (such as multiple sclerosis, spinal cord injury).
Compared with Washington prescribers
Dr. Knowles wrote 17 prescriptions for Tizanidine Hcl, about half as often as the typical Washington prescriber of it (34). Medicare paid $11.30 per fill, versus $12.55 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
Digoxin is used to treat heart failure, usually along with other medications.
Compared with Washington prescribers
Dr. Knowles wrote 16 prescriptions for Digoxin, about half as often as the typical Washington prescriber of it (27). Medicare paid $33.02 per fill, versus $27.48 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 Washington prescribers
Dr. Knowles wrote 15 prescriptions for Donepezil Hcl, about 36% as often as the typical Washington prescriber of it (41). Medicare paid $15.67 per fill, versus $14.15 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 high blood pressure.
Compared with Washington prescribers
Dr. Knowles wrote 15 prescriptions for Lisinopril-Hydrochlorothiazide, about half as often as the typical Washington prescriber of it (27). Medicare paid $12.73 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
Methylprednisolone is used to treat conditions such as arthritis, blood disorders, severe allergic reactions, certain cancers, eye conditions, skin/kidney/intestinal/lung diseases, and immune system disorders.
Compared with Washington prescribers
Dr. Knowles wrote 15 prescriptions for Methylprednisolone, about half as often as the typical Washington prescriber of it (26). Medicare paid $11.27 per fill, versus $8.33 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
Montelukast is used to control and prevent symptoms caused by asthma (such as wheezing and shortness of breath).
Compared with Washington prescribers
Dr. Knowles wrote 15 prescriptions for Montelukast Sodium, about 40% as often as the typical Washington prescriber of it (38). Medicare paid $19.69 per fill, versus $12.60 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 Washington prescribers
Dr. Knowles wrote 15 prescriptions for Tamsulosin Hcl, about 21% as often as the typical Washington prescriber of it (70). Medicare paid $8.96 per fill, versus $16.56 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 Washington prescribers
Dr. Knowles wrote 14 prescriptions for Memantine Hcl, about 31% as often as the typical Washington prescriber of it (45). Medicare paid $21.71 per fill, versus $32.88 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
This medication is used to help relieve severe ongoing pain (such as due to cancer).
Compared with Washington prescribers
Dr. Knowles wrote 14 prescriptions for Morphine Sulfate Er, about 36% as often as the typical Washington prescriber of it (39). Medicare paid $22.33 per fill, versus $30.89 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 Washington prescribers
Dr. Knowles wrote 14 prescriptions for Olmesartan Medoxomil, about half as often as the typical Washington prescriber of it (27). Medicare paid $8.15 per fill, versus $18.25 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 mineral supplement used to treat or prevent low amounts of potassium in the blood.
Compared with Washington prescribers
Dr. Knowles wrote 14 prescriptions for Potassium Chloride, about 28% as often as the typical Washington prescriber of it (50). Medicare paid $18.88 per fill, versus $21.39 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
Clonazepam is used to prevent and control seizures.
Compared with Washington prescribers
Dr. Knowles wrote 13 prescriptions for Clonazepam, about 37% as often as the typical Washington prescriber of it (35). Medicare paid $24.64 per fill, versus $9.50 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 help relieve severe ongoing pain (such as due to cancer).
Compared with Washington prescribers
Dr. Knowles wrote 13 prescriptions for Fentanyl, about half as often as the typical Washington prescriber of it (26). Medicare paid $73.07 per fill, versus $116.18 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
Spironolactone is used to treat high blood pressure and heart failure.
Compared with Washington prescribers
Dr. Knowles wrote 13 prescriptions for Spironolactone, about 32% as often as the typical Washington prescriber of it (41). Medicare paid $7.47 per fill, versus $9.91 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
Esomeprazole is used to treat certain stomach and esophagus problems (such as acid reflux, ulcers).
Compared with Washington prescribers
Dr. Knowles wrote 12 prescriptions for Esomeprazole Magnesium, about 61% as often as the typical Washington prescriber of it (20). Medicare paid $45.28 per fill, versus $49.86 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
Methocarbamol is used to treat muscle spasms/pain.
Compared with Washington prescribers
Dr. Knowles wrote 11 prescriptions for Methocarbamol, about 41% as often as the typical Washington prescriber of it (27). Medicare paid $7.58 per fill, versus $14.08 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
Metoprolol is used with or without other medications to treat high blood pressure (hypertension).
Compared with Washington prescribers
Dr. Knowles wrote 11 prescriptions for Metoprolol Tartrate, about 25% as often as the typical Washington prescriber of it (43). Medicare paid $12.76 per fill, versus $8.03 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
Torsemide is used to reduce extra fluid in the body (edema) caused by conditions such as heart failure, liver disease, and kidney disease.
Compared with Washington prescribers
Dr. Knowles wrote 11 prescriptions for Torsemide, about 29% as often as the typical Washington prescriber of it (38). Medicare paid $23.71 per fill, versus $21.27 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
Rivaroxaban is used to prevent blood clots from forming due to a certain irregular heartbeat (atrial fibrillation) or after hip or knee replacement surgery.
Compared with Washington prescribers
Dr. Knowles wrote 11 prescriptions for Xarelto, about 28% as often as the typical Washington prescriber of it (39). Medicare paid $710.52 per fill, versus $1,017.77 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. Knowles’s prescriptions
What does Dr. Knowles prescribe most?
In 2024 Medicare Part D data, Dr. Knowles's most prescribed medications were Atorvastatin Calcium (100), Losartan Potassium (93) and Hydrocodone-Acetaminophen (78).
How does Dr. Knowles's prescribing compare with other Washington prescribers?
Of the 61 medications with a state comparison, Dr. Knowles prescribes 1 more often than the typical Washington prescriber, 8 about as often and 52 less often. Volume reflects practice size as well as prescribing habits.
Does this list show every medication Dr. Knowles 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 Washington 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.
