FDA approved Indications
Non-FDA Approved Indications
Doxazosin is a quinazoline derivative that acts as a competitive alpha1-antagonist at the post-synaptic receptor.
In Benign Prostatic Hyperplasia
Dose-related Adverse Effects
Common Adverse Effects
In a research study, researchers randomly assigned a total of 3,047 men were randomly assigned to groups of a placebo, doxazosin, or combination therapy with finasteride. Adverse effects of orthostatic hypotension and dizziness occurred significantly more in the groups of doxazosin and combination treatment compared with the placebo group. Rates of adverse effects were reported to peak at year one during a mean duration of 4.5 years of treatment.
Contraindications for the use of doxazosin are:
Effective therapy with doxazosin for its various indications requires titration based upon response and tolerability. Open communication between patients and providers is crucial for successful treatment. Patients should receive education on the different common side effects of doxazosin, and the provider should conduct a thorough review of other medications for possible interactions, paying particular attention to other antihypertensives, nitrates, and PDE-5 inhibitors.
Reports with overdosage and toxicity with the alpha-1 antagonists, including doxazosin, remain very limited in the literature. There is a report of one case of acute doxazosin overdose in 2005. The study found that the patient presented to the emergency department (ED) with drowsiness, decreased blood pressure, and reflex tachycardia but did not have orthostatic hypotension or any other abnormalities. This patient was able to fully awake with supportive therapy in 8 hours and was discharged 48 hours after admission to the ED. Although there are limited works of literature for the toxicity of doxazosin, it appears to have low acute toxicity.
Doxazosin may not be a drug that providers find themselves prescribing daily. However, it has a few key contexts where it proves to be a valuable tool for health care workers in the treatment of BPH, hypertension, ureteral stones, and PTSD associated nightmares. Doxazosin is a medication that requires titration to effective dose and tolerance. As such, health care teams need to monitor patients closely upon the initiation and titration of therapy. The extended-release formulation of doxazosin has the benefit of once-daily dosing and more stable serum concentrations. This dosing regimen reduces the incidence of orthostatic hypotension and various other adverse effects. Because doxazosin has many drug-drug interactions, it may be helpful for a pharmacist to review the different medications that a patient is on before the initiation of therapy.
|||Black L,Naslund MJ,Gilbert TD Jr,Davis EA,Ollendorf DA, An examination of treatment patterns and costs of care among patients with benign prostatic hyperplasia. The American journal of managed care. 2006 Mar; [PubMed PMID: 16551208]|
|||AUA guideline on management of benign prostatic hyperplasia (2003). Chapter 1: Diagnosis and treatment recommendations. The Journal of urology. 2003 Aug; [PubMed PMID: 12853821]|
|||Whelton PK,Carey RM,Aronow WS,Casey DE Jr,Collins KJ,Dennison Himmelfarb C,DePalma SM,Gidding S,Jamerson KA,Jones DW,MacLaughlin EJ,Muntner P,Ovbiagele B,Smith SC Jr,Spencer CC,Stafford RS,Taler SJ,Thomas RJ,Williams KA Sr,Williamson JD,Wright JT Jr, 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Journal of the American College of Cardiology. 2018 May 15; [PubMed PMID: 29146535]|
|||Weber MA,Schiffrin EL,White WB,Mann S,Lindholm LH,Kenerson JG,Flack JM,Carter BL,Materson BJ,Ram CV,Cohen DL,Cadet JC,Jean-Charles RR,Taler S,Kountz D,Townsend RR,Chalmers J,Ramirez AJ,Bakris GL,Wang J,Schutte AE,Bisognano JD,Touyz RM,Sica D,Harrap SB, Clinical practice guidelines for the management of hypertension in the community: a statement by the American Society of Hypertension and the International Society of Hypertension. Journal of clinical hypertension (Greenwich, Conn.). 2014 Jan; [PubMed PMID: 24341872]|
|||Gul U,Yaycıoglu O,Kuzgunbay B,Sarıturk C,Kayra MV,Ozkardes H, Do patients on alpha-blockers for the treatment of benign prostatic hyperplasia have better results after shockwave lithotripsy of urinary stones? Journal of endourology. 2013 May; [PubMed PMID: 23237326]|
|||De Jong J,Wauben P,Huijbrechts I,Oolders H,Haffmans J, Doxazosin treatment for posttraumatic stress disorder. Journal of clinical psychopharmacology. 2010 Feb; [PubMed PMID: 20075659]|
|||Sethi R,Vasudeva S, Doxazosin for the treatment of nightmares: does it really work? A case report. The primary care companion for CNS disorders. 2012; [PubMed PMID: 23469321]|
|||Rodgman C,Verrico CD,Holst M,Thompson-Lake D,Haile CN,De La Garza R 2nd,Raskind MA,Newton TF, Doxazosin XL reduces symptoms of posttraumatic stress disorder in veterans with PTSD: a pilot clinical trial. The Journal of clinical psychiatry. 2016 May; [PubMed PMID: 27249080]|
|||Roepke S,Danker-Hopfe H,Repantis D,Behnia B,Bernard F,Hansen ML,Otte C, Doxazosin, an α-1-adrenergic-receptor Antagonist, for Nightmares in Patients with Posttraumatic Stress Disorder and/or Borderline Personality Disorder: a Chart Review. Pharmacopsychiatry. 2017 Jan; [PubMed PMID: 27276365]|
|||Smith C,Koola MM, Evidence for Using Doxazosin in the Treatment of Posttraumatic Stress Disorder. Psychiatric annals. 2016; [PubMed PMID: 27667865]|
|||Chung M,Vashi V,Puente J,Sweeney M,Meredith P, Clinical pharmacokinetics of doxazosin in a controlled-release gastrointestinal therapeutic system (GITS) formulation. British journal of clinical pharmacology. 1999 Nov; [PubMed PMID: 10594469]|
|||Roehrborn CG,Schwinn DA, Alpha1-adrenergic receptors and their inhibitors in lower urinary tract symptoms and benign prostatic hyperplasia. The Journal of urology. 2004 Mar; [PubMed PMID: 14767264]|
|||Kaplan SA,Lee JY,Meehan AG,Kusek JW, Time Course of Incident Adverse Experiences Associated with Doxazosin, Finasteride and Combination Therapy in Men with Benign Prostatic Hyperplasia: The MTOPS Trial. The Journal of urology. 2016 Jun [PubMed PMID: 26678956]|
|||Satar S,Sebe A,Avci A,Yesilagac H,Gokel Y, Acute intoxication with doxazosin. Human [PubMed PMID: 16004202]|