DoxazosinDoxazosin Mesylate

About Doxazosin

Doxazosin blocks alpha-1 receptors, relaxing smooth muscle in blood vessels and in the prostate and bladder neck, which lowers blood pressure and eases the flow of urine. Immediate-release tablets are labeled for the signs and symptoms of benign prostatic hyperplasia and for high blood pressure, alone or with other blood pressure medicines. They start at 1 mg once a day, morning or evening; for the prostate the dose is raised every one to two weeks to 2, 4 and at most 8 mg, and for blood pressure it can go up to 16 mg once a day. Blood pressure is monitored for at least six hours after the first dose and after each increase. Cardura XL is labeled only for the prostate: it starts at 4 mg with breakfast and can rise to 8 mg after three to four weeks, and its label says it is not indicated for high blood pressure or for women. Safety and effectiveness in children have not been established for either form.

There is no boxed warning. Blood pressure can drop on standing within a few hours of a dose, and fainting is most likely after the first dose or a dose increase, so the label advises against driving or hazardous tasks for 24 hours after the first dose, a dose increase, or restarting after a break. It must not be taken by anyone allergic to doxazosin or to related quinazolines such as prazosin and terazosin. Rarely it causes priapism, a painful erection lasting hours that needs immediate care to prevent permanent impotence. Dizziness and low blood pressure are common with both forms, along with tiredness with the immediate-release tablets and headache and weakness with Cardura XL; neither form is recommended in severe liver impairment.

Before treatment for an enlarged prostate, prostate cancer is ruled out, because it causes similar symptoms. An eye surgeon needs to know about doxazosin before cataract surgery because of intraoperative floppy iris syndrome, even if it was taken only in the past. If treatment stops for several days, it restarts at the starting dose. Cardura XL is swallowed whole, never chewed, cut or crushed; its empty shell may appear in the stool, and it is used with caution in severe narrowing of the gut. The forms are not interchangeable: someone moving from immediate-release tablets to Cardura XL starts at 4 mg and skips the final evening dose of the old tablets.

Taking Doxazosin

How to take it

Immediate-release tablets once a day, in the morning or evening; Cardura XL once a day with breakfast, swallowed whole. Get out of bed slowly, resting your feet on the floor for a few minutes before standing, and sit or lie down if you feel dizzy.

If you miss a dose

Take it as soon as you remember, unless it is almost time for the next dose; then skip the missed dose. Do not take a double dose, and check with the prescriber if you have missed two or more doses, since it may need to restart at the starting dose.

Storage

At room temperature in the original tightly closed container, away from heat and moisture, out of reach of children.

Interactions to know about

Sildenafil, tadalafil and other PDE-5 inhibitors add to its blood pressure lowering and can cause symptomatic low blood pressure; the Cardura XL label says to start one at its lowest dose. Strong CYP3A4 inhibitors such as ketoconazole, clarithromycin and ritonavir can raise doxazosin levels.

This summarizes the official prescribing information. Your prescriber’s and pharmacist’s instructions, and the leaflet that comes with your medicine, take priority.

Why the cash price for Doxazosin differs from pharmacy to pharmacy

Generic immediate-release doxazosin has many makers and costs pharmacies little, so a quote is mostly the dispensing fee and markup, which differ between pharmacies. Starting treatment can mean a new strength every one to two weeks while the dose is raised.

Cardura XL has no generic equivalent, so every fill is priced as a brand. A prescription for one form cannot be filled with the other, so switching needs a new prescription.

Ways to pay less for Doxazosin without insurance

• For immediate-release tablets, ask for generic doxazosin and whether it is on the pharmacy’s flat-price generic list.
• While the dose is being raised, ask the prescriber for quantities that match each step; once it is settled, ask for a ninety-day supply.
• If Cardura XL is prescribed, ask the prescriber whether generic immediate-release doxazosin or tamsulosin would suit you, and ask the maker whether a savings program applies to someone paying cash.
• Upload the prescription to Script Unlock so licensed pharmacies can quote their cash price. You pay the pharmacy directly.

Questions to ask your pharmacist about Doxazosin

1. 1.Is this the immediate-release tablet or Cardura XL, and does my prescription allow a generic?
2. 2.What should I do if I feel faint after the first dose or a dose increase?
3. 3.Is it safe with my erectile dysfunction medicine or other blood pressure medicines?
4. 4.What should I tell my eye surgeon before cataract surgery?

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