- ACRONYMS AND DEFINITIONS
- BPH - Benign prostatic hypertrophy
- 5ARI - 5 alpha reductase inhibitors
Alfuzosin (Uroxatral®)
Dosage forms
Tablet, extended-release
- 10 mg
Dosing
Benign prostatic hyperplasia (BPH)
- Dosing: 10 mg once daily
- Max: 10 mg once daily
- Take with the same meal each day. Food increases absorption. Drug absorption is 50% lower when taken under fasting conditions.
- Do not crush or chew tablets
Kidney disease
- CrCl ≥ 30 ml/min: no dosage adjustment necessary
- CrCl < 30 ml/min: use caution
Liver disease
- Child-Pugh A: has not been studied. Use caution.
- Child-Pugh B and C: DO NOT USE
Generic / Price
- YES/$Doxazosin (Cardura®)
Dosage forms
Tablet
- 1 mg
- 2 mg
- 4 mg
- 8 mg
Dosing
Benign prostatic hyperplasia (BPH)
- Starting: 1 mg once daily
- Maintenance: 1 - 8 mg once daily
- Max: 8 mg once daily
- Increase dose by doubling current dosage at intervals of 1 - 2 weeks
- Postural hypotension may occur when increasing dose, particularly with doses > 4 mg
- May take without regard to food
Hypertension
- Starting: 1 mg once daily
- Maintenance: 1 - 16 mg once daily
- Max: 16 mg once daily
- Increase dose by doubling current dosage
- Postural hypotension may occur when increasing dose, particularly with doses > 4 mg
- May take without regard to food
Kidney disease
- Pharmacokinetic studies in elderly patients and patients with renal impairment have shown no significant alterations compared to younger patients with normal renal function.
Liver disease
- Child-Pugh A and B: monitor for hypotension. Use caution.
- Child-Pugh C: DO NOT USE
Generic / Price
- YES/$Doxazosin (Cardura® XL)
Dosage forms
Tablet, extended-release
- 4 mg
- 8 mg
Dosing
Benign prostatic hyperplasia (BPH)
- Starting: 4 mg once daily
- Maintenance: 4 - 8 mg once daily
- Max: 8 mg once daily
- Increase at intervals of 3 - 4 weeks
- Take with breakfast. Food increases absorption.
- Do not cut, crush, or chew tablet
- If therapy is discontinued for several days, restart at 4 mg dose
- When switching from Cardura® to Cardura® XL, start with 4 mg dose
- Nonabsorbable tablet shell may be seen in stool. This is normal.
Kidney disease
- Manufacturer makes no recommendation
Liver disease
- Child-Pugh A and B: monitor for hypotension. Use caution.
- Child-Pugh C: has not been studied. Not recommended.
Generic / Price
- NO/$$$$Prazosin (Minipress®)
Dosage forms
Capsule
- 1 mg
- 2 mg
- 5 mg
Dosing
Hypertension
- Starting: 1 mg two to three times a day
- Maintenance: 6 - 15 mg/day
- Max: 40 mg/day
- Give in 2 - 3 divided doses
- Doses above 20 mg a day do not typically increase efficacy
- May take without regard to food
Kidney disease
- Manufacturer makes no recommendation
Liver disease
- Manufacturer makes no recommendation
Generic / Price
- YES/$Silodosin (Rapaflo®)
Dosage forms
Capsule
- 4 mg
- 8 mg
Dosing
Benign prostatic hyperplasia (BPH)
- Dosing: 8 mg once daily
- Max: 8 mg once daily
- Take with a meal. Food decreases absorption. In trials, silodosin was always taken with food.
- Capsules may be opened and sprinkled on applesauce. Applesauce should be swallowed immediately and followed with 8 oz of water.
Kidney disease
- CrCl ≥ 50 ml/min: no dose adjustment necessary
- CrCl 30 - 49 ml/min: dose is 4 mg once daily
- CrCl < 30 ml/min: DO NOT USE
Liver disease
- Child-Pugh A and B: no dose adjustment necessary
- Child-Pugh C: has not been studied. Not recommended.
Generic / Price
- YES/$Tamsulosin (Flomax®)
Dosage forms
Capsule
- 0.4 mg
Dosing
Benign prostatic hyperplasia (BPH)
- Starting: 0.4 mg once daily
- Maintenance: 0.4 - 0.8 mg once daily
- Max: 0.8 mg once daily
- Increase dose at intervals of 2 - 4 weeks
- Take one-half hour after the same meal every day. Food slows absorption and may decrease side effects.
- Do not open, crush, or chew capsules
- If therapy is stopped for several days, restart medication at 0.4 mg dose
Kidney disease
- No dosage adjustment necessary in patients with kidney disease. However, it has not been studied in patients with CrCl < 10ml/min.
Liver disease
- Child-Pugh A and B: no dose adjustment necessary
- Child-Pugh C: has not been studied
Generic / Price
- YES/$Terazosin (Hytrin®)
Dosage forms
Capsule
- 1 mg
- 2 mg
- 5 mg
- 10 mg
Dosing
Benign prostatic hyperplasia (BPH)
- Starting: 1 mg once daily at bedtime
- Target: 10 mg once daily
- Max: 20 mg once daily
- Increase dose in stepwise fashion: 2 mg - 5 mg - 10 mg
- It may take 4 - 6 weeks at the 10 mg dose for full BPH symptom response
- Do not open, crush, or chew capsules
- If therapy is stopped for several days, restart medication at 1 mg
- May take without regard to food
Hypertension
- Starting: 1 mg once daily at bedtime
- Maintenance: 1 - 5 mg/day
- Max: 20 mg/day
- May be given once daily or in 2 divided doses
- Increase dose by doubling current dosage
- Do not open, crush, or chew capsules
- If therapy is stopped for several days, restart medication at 1 mg
- May take without regard to food
Kidney disease
- Impaired renal function had no significant effect on the elimination of terazosin, and dosage adjustment of terazosin to compensate for the drug removal during hemodialysis (approximately 10%) does not appear to be necessary.
Liver disease
- Manufacturer makes no recommendation
Generic / Price
- YES/$Jalyn® (tamsulosin + dutasteride)
Dosage forms
Capsule
- Dutasteride - Tamsulosin
- 0.5 mg - 0.4 mg
Dosing
Benign prostatic hyperplasia (BPH)
- Dosing: 0.5/0.4 mg once daily
- Take approximately 30 minutes after the same meal each day. Food slows absorption and may decrease side effects.
- Swallow capsule whole. Do not open or chew. Contact with the contents of the Jalyn capsule may result in irritation of the oropharyngeal mucosa.
Generic / Price
- YES/$$- Kidney disease dosing
- Alfuzosin (Uroxatral®)
- CrCl ≥ 30 ml/min: no dosage adjustment necessary
- CrCl < 30 ml/min: use caution
- Doxazosin (Cardura®)
- Pharmacokinetic studies in elderly patients and patients with renal impairment have shown no significant alterations compared to younger patients with normal renal function.
- Doxazosin (Cardura XL®)
- Manufacturer makes no recommendation
- Prazosin (Minipress®)
- Manufacturer makes no recommendation
- Silodosin (Rapaflo®)
- CrCl ≥ 50 ml/min: no dose adjustment necessary
- CrCl 30 - 49 ml/min: dose is 4 mg once daily
- CrCl < 30 ml/min: DO NOT USE
- Tamsulosin (Flomax®)
- No dosage adjustment necessary in patients with kidney disease. However, it has not been studied in patients with CrCl < 10ml/min.
- Terazosin (Hytrin®)
- Impaired renal function had no significant effect on the elimination of terazosin, and dosage adjustment of terazosin to compensate for the drug removal during hemodialysis (approximately 10%) does not appear to be necessary.
- Liver disease dosing
- Alfuzosin (Uroxatral®)
- Child-Pugh A: has not been studied. Use caution.
- Child-Pugh B and C: DO NOT USE
- Doxazosin (Cardura®)
- Child-Pugh A and B: monitor for hypotension. Use caution.
- Child-Pugh C: DO NOT USE
- Doxazosin (Cardura XL®)
- Child-Pugh A and B: monitor for hypotension. Use caution.
- Child-Pugh C: has not been studied. Not recommended.
- Prazosin (Minipress®)
- Manufacturer makes no recommendation
- Silodosin (Rapaflo®)
- Child-Pugh A and B: no dose adjustment necessary
- Child-Pugh C: has not been studied. Not recommended.
- Tamsulosin (Flomax®)
- Child-Pugh A and B: no dose adjustment necessary
- Child-Pugh C: has not been studied
- Terazosin (Hytrin®)
- Manufacturer makes no recommendation
- DRUG INTERACTIONS
- NOTE: The drug interactions presented here are NOT all-inclusive. Other interactions may exist. Drug interaction checkers provide the most efficient and practical way to check for interactions among multiple medications. A free interaction checker is available from Drugs.com (see Drugs.com interactions checker).
- All Alpha Blockers
- Antipsychotics (Zyprexa®, Risperdal®, Abilify®, etc.) - Antipsychotics can block alpha receptors. When antipsychotics are taken with alpha blockers, risk of orthostatic hypotension may increase
- Mirtazapine (Remeron®) - Mirtazapine blocks alpha receptors. It may potentiate the effects of alpha blockers.
- Phosphodiesterase-5 inhibitors (Viagra®, Cialis®, Levitra®, etc.) - Erectile dysfunction (ED) medications (also called phosphodiesterase-5 inhibitors) and alpha blockers can interact causing a drop in blood pressure. When taking these medications together, patients should be aware of the possibility and take appropriate precautions.
- Precautions that may help attenuate the interaction include:
- Patients should have stable blood pressure on their alpha blocker before starting ED medication
- ED medication should be added to alpha blocker at lowest dose possible
- If patient is already taking ED medication, alpha blocker should be started at lowest dose possible [25]
- Alfuzosin (Uroxatral®)
- Atenolol - Alfuzosin appears to increase blood levels of atenolol and vice versa
- CYP3A strong inhibitors - Strong inhibitors of CYP3A4 can increase alfuzosin blood levels significantly. Alfuzosin should not be taken with strong CYP3A inhibitors. Caution should be used with other CYP3A inhibitors.
- Drugs that prolong the QT interval - Alfuzosin may prolong the QT interval. Do not combine with other QT-prolonging drugs
- Doxazosin (Cardura XL®)
- Constipating medications - Medications that slow the gastrointestinal tract (e.g. anticholinergic medications) can increase the absorption of Cardura XL® and increase its effect.
- Silodosin (Rapaflo®)
- CYP3A strong inhibitors - Strong inhibitors of CYP3A4 can increase silodosin blood levels significantly. Silodosin should not be taken with strong CYP3A inhibitors. Caution should be used with other CYP3A inhibitors.
- P-glycoprotein inhibitors - P-glycoprotein inhibitors can increase silodosin blood levels significantly. Silodosin should not be taken with P-glycoprotein inhibitors.
- Valproic acid (Depakote®) - Silodosin blood levels may be increased by valproic acid
- Tamsulosin (Flomax®)
- CYP3A strong inhibitors - Strong inhibitors of CYP3A4 can increase tamsulosin blood levels significantly. Tamsulosin should not be taken with strong CYP3A inhibitors. Caution should be used with other CYP3A inhibitors.
- CYP2D6 strong inhibitors - Strong inhibitors of CYP2D6 can increase tamsulosin blood levels significantly. Caution should be used when tamsulosin is taken with CYP2D6 inhibitors.
- Terozosin (Hytrin®)
- Verapamil - Terazosin blood levels may be increased by verapamil
| Metabolism and clearance | ||||
|---|---|---|---|---|
| Drug | CYP2C19 | CYP2D6 | CYP3A4 | P-glycoprotein |
| Alfuzosin | - | - | Substrate | - |
| Doxazosin | Substrate | Substrate | Substrate | Inhibitor |
| Prazosin | - | - | - | Substrate and inducer |
| Silodosin | - | - | Substrate | Substrate |
| Tamsulosin | - | Substrate | Substrate | - |
| Terazosin | Not well-defined | |||
- PRICE ($) INFO
Pricing legend
- $ = 0 - $50
- $$ = $51 - $100
- $$$ = $101 - $150
- $$$$ = > $151
- Pricing based on one month of therapy at standard dosing in an adult
- Pricing based on information from GoodRX.com®
- Pricing may vary by region and availability
- BIBLIOGRAPHY
- Manufacturer's package insert