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Doxazosin Disease Interactions

There are 3 disease interactions with doxazosin.


Alpha-1 blockers (applies to doxazosin) hypotension

Moderate Potential Hazard, High plausibility. Applicable conditions: Syncope, Autonomic Neuropathy, Dehydration, Diarrhea, Vomiting

Peripheral alpha 1- adrenergic receptor blocking agents (aka alpha 1- blockers) cause vasodilation and can produce marked hypotension, especially orthostatic hypotension with syncope or other postural symptoms such as dizziness, lightheadedness, and palpitations. Orthostatic effects are most common during initiation of therapy and often occur within 90 minutes after the first dose. However, they can also occur following a dosage increase or resumption of therapy after an interruption of more than a few days. Agents with alpha 1a specificity, such as tamsulosin, act primarily on the prostate but are not devoid of hypotensive effects. Therapy with peripheral alpha-1 blockers should be administered cautiously in patients with or predisposed to hypotensive or syncopal episodes. Caution is also advised in patients who are dehydrated (e.g., due to severe or prolonged diarrhea or vomiting), since they may be more sensitive to the hypotensive effect of the drugs. Therapy should be initiated with the lowest dosage possible and titrated gradually based on patient response and tolerance in accordance with the individual product package labeling. During initiation or reinstitution of therapy and following an increase in dosage, patients should be advised not to rise abruptly from a sitting or recumbent position and to avoid situations where injury could result if syncope occur. Concomitant use of alcohol, extensive periods of standing, prolonged or intense exercise, and exposure to heat can also precipitate orthostatic hypotension and should be minimized. If dizziness, lightheadedness or palpitations occur, the patient should sit or lie down, and seek medical attention if symptoms are recurrent or bothersome.


  1. Grunstein JA (1974) "The problem of postural hypotension." Gerontol Clin (Basel), 16, p. 171-4
  2. Glass AR, Ballou R (1982) "Pheochromocytoma, prazosin, and hypotension." Ann Intern Med, 97, p. 455
  3. Melkild A (1984) "Prazosin (peripress): a long-term study." Curr Med Res Opin, 9, p. 219-28
  4. Graham RM, Thornell IR, Gain JM, Bagnoli C, Oates HF, Stokes GS (1976) "Prazosin: the first-dose phenomenon." Br Med J, 2, p. 1293-4
  5. (1977) "Prazosin (Minipress) for hypertension." Med Lett Drugs Ther, 19, p. 1-2
  6. Salim SS, Mtui EP, Makene WJ (1977) "An open evaluation of the efficacy and toleration of prazosin in patients with hypertension." East Afr Med J, 54, p. 429-33
  7. (2001) "Product Information. Cardura (doxazosin)." Pfizer U.S. Pharmaceuticals
  8. (2001) "Product Information. Hytrin (terazosin)." Abbott Pharmaceutical
  9. Troffa C, Manunta P, Dessifulgheri P, Pazzola A, Sabino G, Patteri G, Tonolo G, Pupita G, Glorioso N, Gitti M, Rappelli A (1994) "Efficacy and tolerability of doxazosin alone or in combination with chlorthalidone in essential hypertension." Curr Ther Res Clin Exp, 55, p. 22-31
  10. Ahaneku JE, Taylor OG, Walker D, Agbedana OE, Salako LA (1994) "Blood pressure and biochemical changes during doxazosin monotherapy in nigerian hypertensive patients." Curr Ther Res Clin Exp, 55, p. 1067-74
  11. Takata Y, Yoshizumi T, Ito Y, Hirota Y, Fujishima M (1995) "Effect of administration and withdrawal of doxazosin on ambulatory blood pressure in patients with essential hypertension." Angiology, 46, p. 11-8
  12. Limbird LE eds., Gilman AG, Hardman JG (1995) "Goodman and Gilman's the Pharmacological Basis of Therapeutics." New York, NY: McGraw-Hill
  13. Roehrborn CG, Siegel RL (1996) "Safety and efficacy of doxazosin in benign prostatic hyperplasia: a pooled analysis of three double-blind, placebo-controlled studies." Urology, 48, p. 406-15
  14. (2001) "Product Information. Flomax (tamsulosin)." Boehringer-Ingelheim
  15. (2003) "Product Information. Uroxatral (alfuzosin)." sanofi-aventis
  16. (2008) "Product Information. Rapaflo (silodosin)." Watson Pharmaceuticals
View all 16 references

Doxazosin (applies to doxazosin) liver disease

Moderate Potential Hazard, High plausibility. Applicable conditions: Biliary Obstruction

Doxazosin is metabolized by the liver and subsequently excreted in the bile, primarily as metabolites, some of which are pharmacologically active. In patients with cirrhosis (Child-Pugh Class A) given a single 2 mg dose, there was a 40% increase in exposure to doxazosin compared to patients with normal hepatic function. The clearance was reduced by 30%, while elimination half-life was not significantly changed. Therapy with doxazosin should be administered cautiously in patients with significantly impaired hepatic or biliary function, since drug and/or metabolite accumulation may occur.


  1. Elliott HL, Meredith PA, Reid JL (1987) "Pharmacokinetic overview of doxazosin." Am J Cardiol, 59, g78-81
  2. Kaye B, Cussans NJ, Faulkner JK, Stopher DA, Reid JL (1986) "The metabolism and kinetics of doxazosin in man, mouse, rat and dog." Br J Clin Pharmacol, 21, s19-25
  3. Young RA, Brogden RN (1988) "Doxazosin. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in mild or moderate hypertension." Drugs, 35, p. 525-41
  4. (2001) "Product Information. Cardura (doxazosin)." Pfizer U.S. Pharmaceuticals
  5. Penenberg D, Chung M, Walmsley P, Vashi V (2000) "The effects of hepatic impairment on the pharmacokinetics of docazosin." J Clin Pharmacol, 40, p. 67-73
View all 5 references

Doxazosin (applies to doxazosin) neutropenia

Moderate Potential Hazard, Moderate plausibility.

Slight but sometimes clinically significant decreases in white blood cell and neutrophil counts have occurred during treatment with some of the peripheral alpha 1-adrenergic receptor blocking agents (aka alpha 1-blockers), including doxazosin. Reported cases were generally asymptomatic and reversible. Patients with preexisting neutropenia or bone marrow depression may require closer monitoring during therapy with alpha 1-blockers.


  1. (2001) "Product Information. Cardura (doxazosin)." Pfizer U.S. Pharmaceuticals

Doxazosin drug interactions

There are 307 drug interactions with doxazosin.

Doxazosin alcohol/food interactions

There is 1 alcohol/food interaction with doxazosin.

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Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.