Prazosin Hcl

Drug overview for PRAZOSIN HCL (prazosin hcl):

Generic name: PRAZOSIN HCL (PRAY-zoe-sin)
Drug class: Alpha-Blockers
Therapeutic class: Cardiovascular Therapy Agents

Prazosin hydrochloride is an alpha1-adrenergic blocking agent.

No enhanced Uses information available for this drug.

DRUG IMAGES

PRAZOSIN 2 MG CAPSULE
PRAZOSIN 5 MG CAPSULE
PRAZOSIN 1 MG CAPSULE

The following indications for PRAZOSIN HCL (prazosin hcl) have been approved by the FDA:

Indications:
Hypertension

Professional Synonyms:
Elevated blood pressure
Essential hypertension
Hyperpiesia
Hyperpiesis
Hypertensive disorder
Systemic arterial hypertension

The following dosing information is available for PRAZOSIN HCL (prazosin hcl):

Dosing
Administration
PRAZOSIN HCL
PRAZOSIN HCL

Dosage of prazosin hydrochloride is expressed in terms of prazosin and must be adjusted according to the patient's blood pressure response and tolerance.

For the management of hypertension in adults, the usual initial dosage of prazosin is 1 mg given 2 or 3 times daily; higher doses should not be used for initial therapy, since initiation of therapy with doses in excess of 1 mg may cause syncope. (See Cautions: Postural Effects.) It has been suggested that syncopal episodes can be minimized by limiting the initial dose of the drug to 1 mg, by subsequently increasing dosage gradually, and by introducing other hypotensive agents into the patient's regimen cautiously. Dosage of prazosin may be gradually increased if necessary to a total dosage of 20 mg daily administered in divided doses.

Higher dosages usually do not increase efficacy, but a few patients may benefit from up to 40 mg of prazosin daily in divided doses. The manufacturer states that the usual maintenance dosage is 6-15 mg daily given in divided doses. For maintenance therapy, prazosin may be administered twice daily in some patients.

Some experts state that the usual dosage range is 2-20 mg daily, administered in 2 or 3 divided doses.

When other hypotensive agents or diuretics are added to existing prazosin therapy, the dosage of prazosin in adults should be reduced to 1 or 2 mg given 3 times daily and gradually increased according to the response and tolerance of the patient.

If prazosin is used for the management of hypertension in children+, some experts have recommended an initial dosage of 0.05-0.1 mg/kg daily given in 3 divided doses; dosage may be increased as necessary to a maximum of 0.5

mg/kg daily given in 3 divided doses. (See Cautions: Pediatric Precautions.) For information on overall principles and expert recommendations for treatment of hypertension in pediatric patients, see Uses: Hypertension in Pediatric Patients, in the Thiazides General Statement 40:28.20.

For the management of hypertension in adults with renal failure, therapy with prazosin should be initiated with 1 mg twice daily. Patients with chronic renal failure may require only small doses of the drug.

Prazosin hydrochloride is administered orally.

Dosing information for PRAZOSIN HCL
DRUG LABEL	DOSING TYPE	DOSING INSTRUCTIONS
PRAZOSIN 1 MG CAPSULE	Maintenance	Adults take 1 capsule (1 mg) by oral route 3 times per day
PRAZOSIN 2 MG CAPSULE	Maintenance	Adults take 1 capsule (2 mg) by oral route 3 times per day
PRAZOSIN 5 MG CAPSULE	Maintenance	Adults take 1 capsule (5 mg) by oral route 2 times per day

Generic dosing information for PRAZOSIN HCL
DRUG LABEL	DOSING TYPE	DOSING INSTRUCTIONS
PRAZOSIN 1 MG CAPSULE	Maintenance	Adults take 1 capsule (1 mg) by oral route 3 times per day
PRAZOSIN 2 MG CAPSULE	Maintenance	Adults take 1 capsule (2 mg) by oral route 3 times per day
PRAZOSIN 5 MG CAPSULE	Maintenance	Adults take 1 capsule (5 mg) by oral route 2 times per day

The following drug interaction information is available for PRAZOSIN HCL (prazosin hcl):

Contraindicated
Severe
Moderate

There are 0 contraindications.

There are 0 severe interactions.

There are 6 moderate interactions. The clinician should assess the patient’s characteristics and take action as needed. Actions required for moderate interactions include, but are not limited to, discontinuing one or both agents, adjusting dosage, altering administration.

Drug Interaction	Drug Names
Selected Beta-Blockers/Selected Alpha-Blockers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Alpha-blockers may cause syncope with sudden loss of consciousness secondary to excessive postural hypotension. Following the first dose of an alpha-blocker, compensatory tachycardia helps to prevent or limit syncope. Beta-blockers may inhibit this tachycardia, thereby worsening alpha-blocker induced hypotension. CLINICAL EFFECTS: The hypotensive effects of an alpha-blocker may be increased in patients on concurrent beta-blocker therapy. PREDISPOSING FACTORS: Patients may be at increased risk of postural hypotension with concurrent diuretic therapy and those on low-sodium diets. PATIENT MANAGEMENT: When starting alpha-blocker therapy in patients receiving beta-blockers, consider initiating treatment with a reduced dose of the alpha-blocker. If syncope occurs, provide supportive treatment as necessary. The adverse effect is self limiting and in most cases does not recur after the initial period of therapy or during subsequent dose titration with the alpha-blocker. DISCUSSION: Beta-blockers increase the acute postural hypotension that frequently follows the first dose of an alpha-blocker. Initiation of beta-blocker therapy in patients that have started taking an alpha-blocker would not be expected to produce acute postural hypotension. Alpha-blockers linked to this interaction include alfuzosin, doxazosin, prazosin, and terazosin. Beta-blockers linked to this interaction include acebutolol, atenolol, betaxolol, bevantolol, levobunolol, metoprolol, nadolol, pindolol, pronethalol, propranolol, and timolol.	ACEBUTOLOL HCL, ATENOLOL, ATENOLOL-CHLORTHALIDONE, BETAXOLOL HCL, BETIMOL, BRIMONIDINE TARTRATE-TIMOLOL, COMBIGAN, CORGARD, COSOPT, COSOPT PF, DORZOLAMIDE-TIMOLOL, HEMANGEOL, INDERAL LA, INDERAL XL, INNOPRAN XL, ISTALOL, KAPSPARGO SPRINKLE, LOPRESSOR, METOPROLOL SUCCINATE, METOPROLOL TARTRATE, METOPROLOL-HYDROCHLOROTHIAZIDE, NADOLOL, PINDOLOL, PROPRANOLOL HCL, PROPRANOLOL HCL ER, PROPRANOLOL-HYDROCHLOROTHIAZID, TENORETIC 100, TENORETIC 50, TENORMIN, TIMOLOL, TIMOLOL MALEATE, TIMOLOL-BIMATOPROST, TIMOLOL-BRIMONI-DORZOL-BIMATOP, TIMOLOL-BRIMONIDIN-DORZOLAMIDE, TIMOLOL-DORZOLAMIDE-BIMATOPRST, TIMOPTIC OCUDOSE, TOPROL XL
Selected Alpha-1 Blockers/Verapamil SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: The exact mechanism is unknown. The bioavailability of prazosin and terazosin are increased. CLINICAL EFFECTS: The hypotensive effects of both drugs may be increased. The incidence of postural hypotension may be greater than with either agent alone. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The combined use of alpha blockers and verapamil may offer therapeutic benefit in the treatment of hypertension. However, blood pressure should be closely monitored when one of these agents is added to the regimen of the other. Adjust the dose of either drug accordingly. The manufacturer of prazosin states this interaction can be minimized by reducing the prazosin dose to 1 to 2 mg three times a day, by introducing antihypertensive drugs cautiously, and by retitrating prazosin based on clinical response.(6) DISCUSSION: Increased serum concentration and area-under-curve (AUC) of prazosin have been reported when starting verapamil in patients receiving prazosin. Both reclining and standing blood pressure increased as did the occurrence of orthostatic hypotension. In a study in 24 subjects, the concurrent administration of terazosin and verapamil resulted in increases in terazosin AUC by 11% after the first dose of verapamil and by 24% after 3 weeks of combined treatment. The time to the maximum concentration (Tmax) of terazosin was decreased. There were no significant changes in verapamil pharmacokinetics.	TRANDOLAPRIL-VERAPAMIL ER, VERAPAMIL ER, VERAPAMIL ER PM, VERAPAMIL HCL, VERAPAMIL SR
CGMP Specific PDE Type-5 Inhibitors/Alpha-Blockers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of avanafil,(1) sildenafil,(2-5) tadalafil,(6-9) or vardenafil(10-14) and an alpha-blocker may result in additive or synergistic effects on blood pressure. CLINICAL EFFECTS: Concurrent use of avanafil,(1) sildenafil,(2-5) tadalafil,(6-9) or vardenafil(10-14)) and an alpha-blocker may result in symptomatic hypotension. PREDISPOSING FACTORS: Patients who have a history of hemodynamic instability on alpha-blocker therapy prior to initiating avanafil, sildenafil, tadalafil, or vardenafil may be at an increased risk of symptomatic hypotension during concurrent therapy. PATIENT MANAGEMENT: The US manufacturer of avanafil states that patients taking alpha-blockers should be stabilized on their alpha-blocker prior to beginning avanafil therapy. Avanafil should be initiated at the 50 mg dosage. In patients stabilized on avanafil therapy, alpha-blocker therapy should be initiated at the lowest possible dosage.(1) The US, Australian, Canadian, and UK manufacturers of sildenafil state that patients taking alpha-blockers should be stabilized on their alpha-blocker prior to beginning sildenafil therapy. Sildenafil should be initiated at the lowest possible dosage. In patients stabilized on sildenafil therapy, alpha-blocker therapy should be initiated at the lowest possible dosage.(2-5) The US manufacturer of tadalafil states that patients taking tadalafil for erectile dysfunction (ED) and alpha-blockers should be stabilized on their alpha-blocker prior to beginning tadalafil therapy. Tadalafil should be initiated at the lowest possible dosage. In patients stabilized on tadalafil therapy, alpha-blocker therapy should be initiated at the lowest possible dose. The combination of tadalafil and an alpha-blocker for treatment of benign prostatic hyperplasia (BPH) is not recommended. Patients on alpha-blocker therapy for BPH should discontinue their alpha-blocker at least one day prior to starting tadalafil for once daily use for the treatment of BPH.(6) The Australian manufacturer of tadalafil states that tadalafil should be used with caution in patients taking alpha-blockers.(7) The Canadian manufacturer of tadalafil states that it may be used with tamsulosin and should be used with caution with other alpha-blockers.(8) The UK manufacturer of tadalafil states that concurrent use with alpha-blockers is not recommended.(9) The US, Canadian, and UK manufacturers of vardenafil state that patients taking alpha-blockers should be stabilized on their alpha-blocker prior to beginning vardenafil therapy. Vardenafil should be initiated at the lowest possible dosage. In patients stabilized on vardenafil therapy, alpha-blocker therapy should be initiated at the lowest possible dosage.(10-12) The UK manufacturer of vardenafil states that vardenafil may be give at any time in relation to tamsulosin; however, a dose separation period of 6 hour should be considered for other alpha-blockers.(12) The Australian manufacturer of vardenafil states that concurrent use with alpha-blockers is not recommended.(13) The US manufacturers of doxazosin,(14) prazosin(15) and terazosin(16) state that PDE-5 inhibitor therapy should be initiated at the lowest dose. DISCUSSION: In a study in 24 subjects, concurrent use of avanafil (200 mg) with doxazosin (1 mg on Day 1, titrated to 8 mg for Days 8-18) resulted in 7 subjects experiencing potentially clinically significant changes in blood pressure.(1) In a study in 24 subjects, concurrent use of avanafil (200 mg) with tamsulosin (0.4 mg Days 1-11) resulted in 5 subjects experiencing potentially clinically significant changes in blood pressure.(1) Simultaneous administration of sildenafil (25 mg) and doxazosin (4 mg) resulted in mean additional reductions of supine blood pressure of 7 mmHg systolic and 7 mmHg diastolic. When doxazosin (4 mg) was simultaneously administered with higher doses of sildenafil, there were reports of symptomatic postural hypotension within one to four hours.(2) In a study, concurrent administration of a single dose of tadalafil (20 mg) to healthy subjects receiving alfuzosin (10 mg daily) resulted in mean maximum decreases in standing and supine systolic blood pressure by 2.2 mmHg and 4.4 mmHg, respectively. There were no subjects with a decrease from baseline standing systolic blood pressure greater than 30 mmHg.(6) In a study, concurrent administration of a single dose of tadalafil (20 mg) to 18 healthy subjects receiving doxazosin (8 mg daily) resulted in significant augmentation of the blood-pressure lowering effects of doxazosin (by 9.8 mmHg). The number of subjects with a standing blood pressure of less than 85 mmHg was greater after concurrent doxazosin and tadalafil than when compared to doxazosin with placebo (28% versus 6%). One subject reported vertigo and another reported dizziness. No syncope was reported.(5,14) In a second study, concurrent administration of a single dose of tadalafil (20 mg) to healthy subjects receiving doxazosin (4-8 mg daily) also resulted in augmentation of the blood-pressure lowering affects of doxazosin. One subject reported symptomatic hypotension and another reported dizziness with concurrent therapy.(6) In a study, concurrent administration of a single dose of tadalafil (20 mg) to healthy subjects receiving tamsulosin (0.4 mg daily) resulted in no significant decreases in blood pressure.(6,17) Hypotension has been reported with concurrent use of terazosin and phosphodiesterase-5 inhibitors.(16) With simultaneous administration of vardenafil (10 mg) and terazosin (10 mg), 6 of 8 healthy subjects experienced a standing systolic blood pressure of less than 85 mmHg. With simultaneous vardenafil (20 mg) and terazosin (10 mg), 2 of 9 subjects experienced a standing systolic blood pressure of less than 85 mmHg. When vardenafil (20 mg) was administered 6 hours apart from terazosin (10 mg), 7 of 28 subjects experienced a standing systolic blood pressure of less than 85 mmHg.(10) With simultaneous administration of vardenafil (10 mg) and tamsulosin (0.4 mg), two of 16 subjects experienced a standing systolic blood pressure of less than 85 mmHg. When vardenafil (20 mg) was administered six hours apart from tamsulosin (0.4 mg), one of 24 subjects experienced a standing systolic blood pressure of less than 85 mmHg.(10) In a study in subjects with benign prostatic hyperplasia (BPH) on stable tamsulosin or terazosin therapy, simultaneous vardenafil (5 mg) and tamsulosin resulted in no effects on blood pressure. Simultaneous vardenafil (5 mg) with terazosin resulted in hypotension in some subjects. This effect did not occur when vardenafil and terazosin were separated by 6 hours.(12) In a placebo controlled, crossover study in 22 subjects with benign prostatic hyperplasia receiving tamsulosin, subjects received single doses of vardenafil (10 mg and 20 mg). No patients exhibited symptomatic hypotension. Three patients receiving 20 mg of vardenafil reported dizziness, but none had a systolic blood pressure of less than 95 mmHg.(18) In a placebo-controlled study in 24 health male subjects, administration of sildenafil (100 mg) or tadalafil (20 mg) with silodosin resulted in an increase in positive orthostatic tests in the 12 hours after concurrent administration when compared with the administration of silodosin alone. There were no reports of symptomatic orthostasis or dizziness.(19)	ADCIRCA, ALYQ, AVANAFIL, CIALIS, ENTADFI, OPSYNVI, REVATIO, SILDENAFIL CITRATE, STENDRA, TADALAFIL, TADLIQ, VARDENAFIL HCL, VIAGRA
Selected MAOIs/Selected Antihypertensive Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Both MAOIs and antihypertensive agents may increase the risk of postural hypotension.(1,2) CLINICAL EFFECTS: Postural hypotension may occur with concurrent therapy of MAOIs and antihypertensive agents.(1,2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of phenelzine states all patients should be followed closely for symptoms of postural hypotension. Hypotensive side effects have occurred in patients who have been hypertensive and normotensive, as well as hypotensive at initiation of phenelzine.(1) The manufacturer of tranylcypromine states hypotension has been observed most commonly but not exclusively in patients with pre-existing hypertension. Tranylcypromine doses greater than 30 mg daily have a major side effect of postural hypotension and can lead to syncope. Gradual dose titration is recommended to decrease risk of postural hypotension. Combined use with other agents known to cause hypotension have shown to have additive side effects and should be monitored closely.(2) Monitor the patient for signs and symptoms of postural hypotension including dizziness, lightheadedness, or weakness, especially upon standing. Monitor blood pressure as well as orthostatic vitals and adjust antihypertensive therapy, including decreasing the dose, dividing doses, or scheduling doses at bedtime, as needed to maintain goal blood pressure. If blood pressure remains hypotensive, consider decreasing the dose of phenelzine or tranylcypromine. In some cases, discontinuation of one or both agents may be necessary.(3) Normotensive patients on stable antihypertensive therapy who are started on either phenelzine or tranylcypromine may be at increased risk for hypotension. Hypertensive patients on stable phenelzine or tranylcypromine who require antihypertensive therapy would be at decreased risk for hypotension. DISCUSSION: A review article describes the pharmacology of phenelzine and tranylcypromine as non-selective MAOIs which inhibit both type A and type B substrates. Orthostatic hypotension is described as the most common MAOI side effect and usually occurs between initiation and the first 3-4 weeks of therapy.(3) In a double-blind study, 71 patients were randomized to receive a 4-week trial of either tranylcypromine, amitriptyline, or the combination. The number of patients reporting dizziness at 4 weeks was not different between the three treatment groups (tranylcypromine 52.4%; amitriptyline 65%; combination 66.7%). Blood pressure (BP) assessment noted a significant drop in standing BP in the tranylcypromine group compared to baseline (systolic BP change = -10 mmHg; p<0.02 and diastolic BP change = -9 mmHg; p<0.02). Combination therapy also had a significant drop in standing BP compared to baseline (systolic BP change = -9 mmHg; p<0.02). Patients receiving amitriptyline had no significant change in BP from baseline at 4 weeks. All three groups had a trend toward increasing orthostatic hypotension in BP changes from lying to standing. The change in orthostatic hypotension was significant in the amitriptyline group with an average systolic BP orthostatic drop of -9 mmHg (p<0.05).(4) A randomized, double-blind study of 16 inpatients with major depressive disorder were treated with either phenelzine or tranylcypromine. Cardiovascular assessments were completed at baseline and after 6 weeks of treatment. After 6 weeks, 5/7 patients (71%) who received phenelzine had a decrease in standing systolic BP greater than 20 mmHg from baseline. Head-up tilt systolic and diastolic BP decreased from baseline in patients on phenelzine (98/61 mmHg v. 127/65 mmHg, respectively; systolic change p=0.02 and diastolic change p=0.02). After 6 weeks, 6/9 patients (67%) who received tranylcypromine had a decrease in standing systolic BP greater than 20 mmHg from baseline. Head-up tilt systolic and diastolic BP decreased from baseline in patients on tranylcypromine (113/71 mmHg v. 133/69 mmHg, respectively; systolic change p=0.09 and diastolic change p=0.07).(5) Selected MAOIs linked to this monograph include: phenelzine and tranylcypromine. Selected antihypertensive agents include: ACE inhibitors, alpha blockers, ARBs, beta blockers, calcium channel blockers, aprocitentan, clonidine, hydralazine and sparsentan.	NARDIL, PARNATE, PHENELZINE SULFATE, TRANYLCYPROMINE SULFATE
Tizanidine/Selected Antihypertensives SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Tizanidine is an alpha-2 agonist. Concurrent use with antihypertensive agents may result in additive effects on blood pressure.(1) CLINICAL EFFECTS: Concurrent use of antihypertensives and tizanidine may result in hypotension.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Patients receiving concurrent therapy should be monitored for hypotension. The risk of hypotension may be decreased by careful titration of tizanidine dosages and monitoring for hypotension prior to dose advancement. Counsel patients about the risk of orthostatic hypotension.(1) DISCUSSION: Severe hypotension has been reported following the addition of tizanidine to existing lisinopril therapy.(2-4)	TIZANIDINE HCL, ZANAFLEX
Apomorphine/Selected Antihypertensives and Vasodilators SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Apomorphine causes dose-dependent decreases in blood pressure. Concurrent use with antihypertensive agents may result in additive effects on blood pressure.(1) CLINICAL EFFECTS: Concurrent use of antihypertensives and apomorphine may result in orthostatic hypotension with or without dizziness, nausea, or syncope.(1) PREDISPOSING FACTORS: The risk of orthostatic hypotension may be increased during dose escalation of apomorphine and in patients with renal or hepatic impairment.(1) PATIENT MANAGEMENT: Patients receiving concurrent therapy should be monitored for hypotension. Counsel patients about the risk of orthostatic hypotension.(1) DISCUSSION: Healthy volunteers who took sublingual nitroglycerin (0.4 mg) concomitantly with apomorphine experienced a mean largest decrease in supine systolic blood pressure (SBP) of 9.7 mm Hg and in supine diastolic blood pressure (DBP) of 9.3 mm Hg, and a mean largest decrease in standing SBP and DBP of 14.3 mm Hg and 13.5 mm Hg, respectively. The maximum decrease in SBP and DBP was 65 mm Hg and 43 mm Hg, respectively. When apomorphine was taken alone, the mean largest decrease in supine SBP and DBP was 6.1 mm Hg and 7.3 mm Hg, respectively, and in standing SBP and DBP was 6.7 mm Hg and 8.4 mm Hg, respectively.(1)	APOKYN, APOMORPHINE HCL, ONAPGO

Severe List
Orthostatic hypotension

Moderate List
Cataract surgery
Intraoperative floppy iris syndrome

The following adverse reaction information is available for PRAZOSIN HCL (prazosin hcl):

Overview
Severe
Less Severe

Adverse reaction overview.

No enhanced Common Adverse Effects information available for this drug.

There are 16 severe adverse reactions.

More Frequent	Less Frequent
Dizziness Orthostatic hypotension	Edema Palpitations Syncope Tachycardia

Rare/Very Rare
Abdominal pain with cramps Abnormal hepatic function tests Angina Bradycardia Dyspnea Intraoperative floppy iris syndrome Pancreatitis Priapism Urticaria Vasculitis

There are 30 less severe adverse reactions.

More Frequent	Less Frequent
Drowsy Headache disorder	Constipation Diarrhea Fatigue Hypotension Malaise Nausea Nervousness Paresthesia Skin rash Vomiting Xerostomia

Rare/Very Rare
Accidental fall Alopecia Arthralgia Blurred vision Depression Epistaxis Erectile dysfunction Fever General weakness Hallucinations Hyperhidrosis Increased urinary frequency Nasal congestion Pruritus of skin Tinnitus Urinary incontinence Vertigo

The following precautions are available for PRAZOSIN HCL (prazosin hcl):

Pediatric
Pregnant
Lactation
Geriatric

No enhanced Pediatric Use information available for this drug.

Contraindicated

None

Severe Precaution

None

Management or Monitoring Precaution

None

Prazosin hydrochloride has been associated with decreased litter size at birth and at 1, 4, and 21 days of age in rats receiving more than 225 times the usual maximum recommended human dosage; no evidence of drug-related external, visceral, or skeletal fetal abnormalities was observed. No prazosin-related external, visceral, or skeletal abnormalities were observed in the offspring of pregnant rabbits and monkeys receiving dosages more than 225 and 12 times the usual maximum recommended human dosage, respectively. Prazosin has been used alone or in combination with other hypotensive agents for the management of severe hypertension in a limited number of pregnant women without apparent adverse effect on the fetus. There are no adequate and well-controlled studies to date using prazosin in pregnant women, however, and the drug should be used during pregnancy only when the potential benefits justify the possible risks to the fetus.

Since prazosin is distributed into milk in small amounts, the drug should be used with caution in nursing women.

No enhanced Geriatric Use information available for this drug.

The following icd codes are available for PRAZOSIN HCL (prazosin hcl)'s list of indications:

Hypertension
I10	Essential (primary) hypertension
I11	Hypertensive heart disease
I11.0	Hypertensive heart disease with heart failure
I11.9	Hypertensive heart disease without heart failure
I12	Hypertensive chronic kidney disease
I12.0	Hypertensive chronic kidney disease with stage 5 chronic kidney disease or end stage renal disease
I12.9	Hypertensive chronic kidney disease with stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease
I13	Hypertensive heart and chronic kidney disease
I13.0	Hypertensive heart and chronic kidney disease with heart failure and stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease
I13.1	Hypertensive heart and chronic kidney disease without heart failure
I13.10	Hypertensive heart and chronic kidney disease without heart failure, with stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease
I13.11	Hypertensive heart and chronic kidney disease without heart failure, with stage 5 chronic kidney disease, or end stage renal disease
I13.2	Hypertensive heart and chronic kidney disease with heart failure and with stage 5 chronic kidney disease, or end stage renal disease
I15.1	Hypertension secondary to other renal disorders