Diblocin - General Information
A selective alpha-1-adrenergic blocker that lowers serum cholesterol. It is also effective in the treatment of hypertension. [PubChem]
Pharmacology of Diblocin
Diblocin is an alpha-adrenergic blocking agent used to treat hypertension and benign prostatic hyperplasia. Accordingly, Diblocin is a selective inhibitor of the alpha1 subtype of alpha adrenergic receptors. In the human prostate, Diblocin antagonizes phenylephrine (alpha1 agonist)-induced contractions, in vitro, and binds with high affinity to the alpha1c adrenoceptor, which is thought to be the predominant functional type in the prostate. Studies in normal human subjects have shown that Diblocin competitively antagonized the pressor effects of phenylephrine (an alpha1 agonist) and the systolic pressor effect of norepinephrine. The antihypertensive effect of Diblocin results from a decrease in systemic vascular resistance and the parent compound Diblocin is primarily responsible for the antihypertensive activity.
Diblocin for patients
Before you start taking doxazosin mesylate.
Each time you get a new prescription.
You and your doctor should discuss this treatment and your BPH symptoms before you start taking doxazosin mesylate and at your regular checkups. This leaflet does NOT take the place of discussions with your doctor.
Doxazosin mesylate is used to treat both benign prostatic hyperplasia (BPH) and high blood pressure (hypertension). This leaflet describes doxazosin mesylate as treatment for BPH (although you may be taking doxazosin mesylate for both your BPH and high blood pressure).
Doxazosin mesylate works on a specific type of muscle found in the prostate, causing it to relax. This in turn decreases the pressure within the prostate, thus improving the wflow of urine and your symptoms.
Doxazosin mesylate helps relieve the symptoms of BPH (weak stream, start-and-stop stream, a feeling that your bladder is not completely empty, delay in beginning of urination, need to urinate often during the day and especially at night, and feeling that you must urinate immediately). It does not change the size of the prostate. The prostate may continue to grow; however, a larger prostate is not necessarily related to more symptoms or to worse symptoms. Doxazosin mesylate can decrease your symptoms and improve urinary flow, without decreasing the size of the prostate.
If doxazosin mesylate is helping you, you should notice an effect within 1 to 2 weeks after you start your medication. Doxazosin mesylate has been studied in over 900 patients for up to 2 years and the drug has been shown to continue to work during long-term treatment. Even though you take doxazosin mesylate and it may help you, doxazosin mesylate may not prevent the need for surgery in the future.
Doxazosin mesylate does not affect PSA levels. PSA is the abbreviation for Prostate Specific Antigen. Your doctor may have done a blood test called PSA. You may want to ask your doctor more about this if you have had a PSA test done.
Other Important Facts
You should see an improvement of your symptoms within 1 to 2 weeks. In addition to your other regular checkups you will need to continue seeing your doctor regularly to check your progress regarding your BPH and to monitor your blood pressure.
Doxazosin mesylate is not a treatment for prostate cancer. Your doctor has prescribed doxazosin mesylate for your BPH and not for prostate cancer; however, a man can have BPH and prostate cancer at the same time. Doctors usually recommend that men be checked for prostate cancer once a year when they turn 50 (or 40 if a family member has had prostate cancer). A higher incidence of prostate cancer has been noted in men of African-American descent. These checks should continue even if you are taking doxazosin mesylate.
How To Take Doxazosin Mesylate and What You Should Know While Taking Doxazosin Mesylate for BPH
Doxazosin mesylate can cause a sudden drop in blood pressure after the VERY FIRST DOSE. You may feel dizzy, faint or �light-headed,� especially after you stand up from a lying or sitting position. This is more likely to occur after you've taken the first few doses or if you increase your dose, but can occur at any time while you are taking the drug. It can also occur if you stop taking the drug and then restart treatment. If you feel very dizzy, faint or �light-headed� you should contact your doctor. Your doctor will discuss with you how often you need to visit and how often your blood pressure should be checked.
Your blood pressure should be checked when you start taking doxazosin mesylate even if you do not have high blood pressure (hypertension). Your doctor will discuss with you the details of how blood pressure is measured.
Most (98%) of plasma doxazosin is protein bound. In vitro data in human plasma indicate that doxazosin mesylate has no effect on protein binding of digoxin, warfarin, phenytoin or indomethacin. There is no information on the effect of other highly plasma protein bound drugs on doxazosin binding. Doxazosin mesylate has been administered without any evidence of an adverse drug interaction to patients receiving thiazide diuretics, beta-blocking agents, and nonsteroidal anti-inflammatory drugs. In a placebo-controlled trial in normal volunteers, the administration of a single 1 mg dose of doxazosin on day 1 of a four-day regimen of oral cimetidine (400 mg twice daily) resulted in a 10% increase in mean AUC of doxazosin (p=0.006), and a slight but not statistically significant increase in mean Cmax and mean half-life of doxazosin. The clinical significance of this increase in doxazosin AUC is unknown.
In clinical trials, doxazosin mesylate tablets have been administered to patients on a variety of concomitant medications; while no formal interaction studies have been conducted, no interactions were observed. Doxazosin mesylate tablets have been used with the following drugs or drug classes:
1. Analgesic/anti-inflammatory (e.g., acetaminophen, aspirin, codeine and codeine combinations, ibuprofen, indomethacin).
2. Antibiotics (e.g., erythromycin, trimethoprim and sulfamethoxazole, amoxicillin).
3. Antihistamines (e.g., chlorpheniramine).
4. Cardiovascular agents (e.g., atenolol, hydrochlorothiazide, propranolol).
6. Gastrointestinal agents (e.g., antacids).
7. Hypoglycemics and endocrine drugs.
8. Sedatives and tranquilizers (e.g., diazepam).
9. Cold and flu remedies.
Doxazosin mesylate is contraindicated in patients with a known sensitivity to quinazolines (e.g., prazosin, terazosin) or any of the inert ingredients.
Additional information about Diblocin
Diblocin Indication: For treatment and management of Hypertension and urinary obstruction symptoms of BPH.
Mechanism Of Action: Diblocin acts by inhibiting the postsynaptic alpha(1)-adrenoceptors on vascular smooth muscle. This inhibits the vasoconstrictor effect of circulating and locally released catecholamines (epinephrine and norepinephrine), resulting in peripheral vasodilation.
Drug Interactions: Tadalafil Risk of significant hypotension with this association
Vardenafil Risk of significant hypotension with this association
Food Interactions: Avoid alcohol.
Avoid natural licorice.
Take without regard to meals.
Generic Name: Doxazosin
Synonyms: Not Available
Drug Category: Vasodilator Agents; Antihypertensive Agents; Anticholesteremic Agents; Alpha-adrenergic Blocking Agents
Drug Type: Small Molecule; Approved
Toxicity (Overdose): Symptoms of overdose include hypotension. Oral LD50 is greater than 1000 mg/kg in mice and rats.
Protein Binding: 98%
Half Life: 22 hours
Dosage Forms of Diblocin: Tablet Oral
Chemical IUPAC Name: [4-(4-amino-6,7-dimethoxyquinazolin-2-yl)piperazin-1-yl]-(2,3-dihydro-1,4-benzodioxin-2-yl)methanone
Chemical Formula: C23H25N5O5
Doxazosin on Wikipedia: https://en.wikipedia.org/wiki/Doxazosin
Organisms Affected: Humans and other mammals