Cardura/Cardura XL Special Precautions

Postural Hypotension/Syncope: As with all alpha-blockers, a very small percentage of patients have experienced postural hypotension evidenced by dizziness and weakness, or rarely loss of consciousness (syncope), particularly with the commencement of therapy. When instituting therapy with any effective alpha-blocker, the patient should be advised how to avoid symptoms resulting from postural hypotension and what measures to take should they develop. The patient should be cautioned to avoid situations where injury could result should dizziness or weakness occur during the initiation of doxazosin therapy.
Use with Phosphodiesterase Type-5 Inhibitors: Concomitant administration of doxazosin with a phosphodiesterase type-5 (PDE-5) inhibitor should be used with caution as it may lead to symptomatic hypotension in some patients.
Impaired Hepatic Function: As with any drug wholly metabolized by the liver, doxazosin should be administered with caution to patients with evidence of impaired hepatic function (see Pharmacology: Pharmacokinetics under Actions).
Intraoperative Floppy Iris Syndrome: The intraoperative floppy iris syndrome (IFIS), a variant of small pupil syndrome has been observed during cataract surgery in some patients on or previously treated with alpha₁-blockers. As IFIS may lead to increased procedural complications during the operation, current or past use of alpha-blockers should be made known to the ophthalmologic surgeon in advance of surgery.
Priapism: Prolonged erections and priapism have been reported with alpha-1 blockers including doxazosin in post-marketing experience. In the event of an erection that persists longer than 4 hours, the patient should seek immediate medical assistance. If priapism is not treated immediately, penile tissue damage and permanent loss of potency could result.
Information for Patients: Patients should be informed that doxazosin GITS should be swallowed whole. Patients should not chew, divide or crush the tablets. Patients should not be concerned if they occasionally notice in their stool something that looks like a tablet. In doxazosin GITS, the medication is contained within a non-absorbable shell that has been specially designed to slowly release the drug so the body can absorb it. When this process is completed, the empty tablet is eliminated from the body.
Effects on Ability to Drive and Use Machines: The ability to engage in activities such as operating machinery or operating a motor vehicle may be impaired, especially when initiating doxazosin/doxazosin GITS therapy.
Cardura XL: Use with Phosphodiesterase Type-5 Inhibitors: No studies have been conducted with doxazosin GITS.
Gastrointestinal Disorders: Markedly reduced gastrointestinal (GI) retention times of doxazosin GITS may influence the pharmacokinetic profile and hence the clinical efficacy of the drug. As with any other non-deformable material, caution should be used when administering doxazosin GITS in patients with preexisting severe GI narrowing (pathologic or iatrogenic).
There have been rare reports of obstructive symptoms in patients with known strictures in association with the ingestion of another drug in this non-deformable sustained-release formulation.