Prazosin Hydrochloride

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

When prazosin is administered with diuretics or other hypotensive agents, particularly beta-adrenergic blocking agents (eg, propranolol), the hypotensive effect of prazosin may be increased.

... prazosin hydrochloride has been administered without any adverse drug interaction in limited clinical experience to date with the following: cardiac glycosides -- digitalis and digoxin; hypoglycemics -- insulin, chlorpropamide, phenformin, tolazamide, and tolbutamide; tranquilizers and sedatives -- chlordiazepoxide, diazepam, phenobarbital; antigout -- allopurinol, colchicine, and probenecid; antiarrhythmics -- procainamide, propranolol and quinidine; analgesics, antipyretics and anti-inflammatories -- propoxyphene, aspirin, indomethacin, and phenylbutazone.

/HUMAN EXPOSURE STUDIES/ In overdosage, hypotension and CNS depression ranging from lethargy to coma are reported. In addition, priapism may occur.

/CASE REPORTS/ Ingestion of at least 50 mg of prazosin by a 2 yr old child produced profound drowsiness and depressed reflexes. There was no decrease in blood pressure and recovery was uneventful. A 19 yr old man who ingested approximately 200 mg of prazosin had normal CNS responses and slightly decreased blood pressure.

Drug Induced Liver Injury Rank (DILIrank 2.0)

Prazosin hydrochloride

Ambiguous-DILI-concern

3

Adverse reactions

DOI:10.1016/j.drudis.2016.02.015

/LABORATORY ANIMALS: Acute Exposure/ ... Prazosin has been shown to exacerbate canine narcolepsy-cataplexy, probably secondary to inhibition of a subtype of alpha1-adrenergic receptor (eg, alpha1b) in the CNS.

/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ No carcinogenic potential was demonstrated in an 18 month study in rats with /prazosin hydrochloride/ ... at dose levels more than 225 times the usual maximum recommended human dose of 20 mg per day.

/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ /prazosin hydrochloride/ ... has been shown to be associated with decreased litter size at birth 1, 4, and 21 days of age in rats when given doses more than 225 times the usual maximum recommended human dose. No evidence of drug-related external, visceral, or skeletal fetal abnormalities were observed. No drug-related external, visceral, or skeletal abnormalities were observed in fetuses of pregnant rabbits and pregnant monkeys at doses more than 225 times and 12 times the usual maximum recommended human dose respectively.

/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ Decreased fertility has occurred in male and female rats receiving prazosin dosages of 75 mg/kg but did not occur in those receiving 25 mg/kg. Testicular changes consisting of atrophy and necrosis have occurred in rats and dogs receiving prazosin dosages of 25 mg/kg daily for a year or longer but no such changes occurred in those receiving 10 mg/kg daily.

For more Non-Human Toxicity Excerpts (Complete) data for PRAZOSIN HYDROCHLORIDE (6 total), please visit the HSDB record page.

Treatment with supportive care including intravenous fluid boluses and vasopressors such as dopamine were effective in the few overdose cases reported.

Maintain an open airway and assist ventilation if necessary.Hypotension usually respondes to supine positioning and iv crystalloid fluids. Occasionally pressor therapy is needed. there is no specific antidote. Administer activated charcoal.

Manufacturers, packers, and distributors of drug and drug products for human use are responsible for complying with the labeling, certification, and usage requirements as prescribed by the Federal Food, Drug, and Cosmetic Act, as amended (secs 201-902, 52 Stat. 1040 et seq., as amended; 21 U.S.C. 321-392).

The Approved Drug Products with Therapeutic Equivalence Evaluations List identifies currently marketed prescription drug products, incl prazosin hydrochloride, approved on the basis of safety and effectiveness by FDA under sections 505 of the Federal Food, Drug, and Cosmetic Act.

MEDICATION

Use (kg; approx.) in Germany (2009): >10

Oral Capsules, 1 mg (of prazosin), Minipress, Pifizer; 2 mg (of prazosin), Minipress, Pifzer; 5 mg (of prazosin), Minipress, Pifizer.

Oral Capsules, 1 mg (of prazosin) with Polythiazide 0.5 mg, Minizide 1, Pifizer; 2 mg (of prazosin) with Polythiazide 0.5 mg, Minizide 2, Pfizer; 5 mg (of prazosin) with Polythiazide 0.5 mg, Minizide 5, Pfizer.

Capsules, 1, 2, and 5 mg /Prazosin HCl/

1-(4-Amino-6,7-dimethoxy-2-quinazolinyl)-4-(2-furanylcarbonyl)piperazine.

2-(4-(2-FUROYL)PIPERAZIN-1-YL)-4-AMINO-6,7-DIMETHOXYQUINAZOLINE