Tezruly

Dosage for Terazosin must be individualized and titrated (gradually increased) based on patient response to minimize the risk of severe hypotension (low blood pressure) and syncope (fainting).

Benign Prostatic Hyperplasia (BPH)

• Initial Dose: 1 mg taken at bedtime. This 'starting low' approach is mandatory to prevent the 'first-dose effect.'
• Titration: The dose may be increased in a stepwise fashion to 2 mg, 5 mg, or 10 mg once daily to achieve the desired improvement in symptoms and flow rates.
• Maintenance Dose: Most patients respond well to a dose of 5 mg to 10 mg once daily. The maximum recommended dose for BPH is typically 20 mg per day, though benefits often plateau at 10 mg.

Hypertension

• Initial Dose: 1 mg at bedtime.
• Titration: The dose may be slowly increased by your doctor. Common maintenance ranges are 1 mg to 5 mg once daily.
• Maximum Dose: Some patients may require up to 20 mg per day, but if 20 mg does not control blood pressure, your healthcare provider will likely add another medication rather than increasing the Terazosin dose further.

Terazosin is not FDA-approved for use in pediatric patients. The safety and effectiveness of this medication in children have not been established. Healthcare providers generally avoid prescribing this medication to individuals under the age of 18.

Renal Impairment

In patients with renal insufficiency (kidney problems), the pharmacokinetic profile of Terazosin does not change significantly. Therefore, no specific dosage adjustment is typically required for patients with mild to moderate renal impairment. However, cautious monitoring is always advised.

Hepatic Impairment

Because Terazosin is metabolized in the liver and excreted via bile, patients with significant hepatic impairment (liver disease) should be treated with caution. Lower starting doses and slower titration may be necessary, as the drug may accumulate in the body.

Elderly Patients

Geriatric patients (those over 65) may be more sensitive to the hypotensive effects of Terazosin. There is an increased risk of dizziness and falls. Clinical trials suggest that while the efficacy is similar to younger adults, the titration should be performed with extra care.

• Timing: The very first dose, and every subsequent dose increase, should be taken at bedtime. This reduces the risk of injury if you experience dizziness or fainting.
• Consistency: Take the medication at the same time every day. It can be taken with or without food.
• Administration: Swallow the capsules whole. Do not crush or chew them unless specifically instructed by a pharmacist.
• Storage: Store the medication at room temperature (68°F to 77°F or 20°C to 25°C), away from moisture, heat, and direct light.

If you miss a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and return to your regular schedule. Do not double the dose to catch up. If you miss several days of Terazosin, do not restart at your maintenance dose. You must contact your doctor, as you may need to restart at the 1 mg 'starter' dose to avoid severe low blood pressure.

An overdose of Terazosin can lead to severe hypotension. Symptoms may include extreme dizziness, fainting, blurred vision, and a rapid or irregular heartbeat.

• Emergency Measures: If an overdose is suspected, the patient should be placed in a supine position (lying on their back) with legs elevated to help restore blood flow to the brain. Seek emergency medical attention immediately or contact a poison control center.

> Important: Follow your healthcare provider's dosing instructions exactly. Do not adjust your dose or stop taking the medication without medical guidance, as this could cause your blood pressure to spike or your BPH symptoms to return rapidly.

The most frequently reported side effects of Terazosin are related to its vasodilatory properties (widening of blood vessels). These are often most prominent during the first few days of treatment or when the dose is increased.

• Dizziness and Vertigo: A feeling of lightheadedness or spinning. This is most common when rising from a sitting or lying position.
• Headache: Generally mild to moderate, occurring as the body adjusts to the medication.
• Asthenia (Weakness): A general feeling of tiredness or lack of energy.
• Somnolence: Feeling unusually sleepy or drowsy during the day.
• Nasal Congestion: Stuffy nose caused by the relaxation of blood vessels in the nasal passages.

• Peripheral Edema: Swelling of the hands, ankles, or feet due to fluid retention.
• Palpitations: Feeling like your heart is racing, fluttering, or skipping a beat.
• Nausea: Mild stomach upset, which often resolves over time.
• Blurred Vision: Temporary changes in vision as the eyes adjust to changes in blood pressure.
• Dyspnea: Shortness of breath, particularly during physical activity.

• Priapism: A painful, prolonged erection lasting more than four hours. This is a medical emergency.
• Syncope (Fainting): Complete loss of consciousness, usually occurring within 30 to 90 minutes of the first dose or a dose increase.
• Allergic Reactions: Rash, itching, or hives.
• Impotence: While less common than with other blood pressure meds (like beta-blockers), some men report changes in sexual function.

> Warning: Stop taking Terazosin and call your doctor immediately if you experience any of these serious symptoms:

1. 1Fainting or Severe Lightheadedness: Especially if it occurs after your first dose or a dose increase.
2. 2Chest Pain (Angina): Terazosin can occasionally trigger or worsen chest pain in people with underlying heart disease.
3. 3Priapism: An erection that lasts longer than 4 hours. If not treated immediately, this can lead to permanent erectile dysfunction.
4. 4Signs of a Severe Allergic Reaction: Swelling of the face, lips, tongue, or throat; difficulty breathing; or severe skin rash.
5. 5Sudden Vision Loss or Changes: Especially important if you are planning eye surgery.

With prolonged use, most patients develop a tolerance to the dizziness and lightheadedness associated with Terazosin. However, long-term use requires monitoring for:

• Weight Gain: Some patients experience modest weight gain due to fluid retention (edema).
• Tolerance: In some cases of hypertension, the body may adapt, requiring a dose adjustment or the addition of a second medication.
• Cardiovascular Outcomes: While Terazosin lowers blood pressure, it is generally not the first choice for long-term prevention of heart failure compared to other classes like ACE inhibitors.

No FDA black box warnings currently exist for Terazosin. However, the 'First-Dose Effect' is considered a major clinical warning that carries similar weight in prescribing practices. Healthcare providers are trained to emphasize the risk of syncope with the initial dose.

Report any unusual symptoms or side effects to your healthcare provider. Keeping a log of your blood pressure and any symptoms can help your doctor manage your treatment effectively.

Terazosin is associated with a phenomenon known as the 'First-Dose Effect.' This refers to a sudden and significant drop in blood pressure that can lead to fainting (syncope), especially when the patient stands up. This effect is most likely to occur within 30 to 90 minutes after the very first dose, after a significant increase in dosage, or when restarting the medication after a break. To minimize this risk, the initial dose is strictly limited to 1 mg and should be taken at bedtime.

There are currently no FDA black box warnings for Terazosin. However, the risk of syncope is highlighted prominently in the 'Warnings' section of the official prescribing information.

• Orthostatic Hypotension: Patients should be warned about the possibility of dizziness or lightheadedness when rising from a chair or bed. It is advised to 'dangle' the feet over the side of the bed for a minute before standing up.
• Intraoperative Floppy Iris Syndrome (IFIS): If you are planning to have cataract or glaucoma surgery, you must inform your ophthalmologist (eye surgeon) that you are taking or have previously taken Terazosin. Alpha-blockers can cause the iris to become 'floppy' during surgery, which can lead to complications. Most surgeons recommend not stopping the drug, but they need to adjust their surgical technique.
• Priapism: Though rare, alpha-1 antagonists like Terazosin have been linked to priapism. This is a serious condition that requires immediate urological intervention to prevent tissue damage.
• Prostate Cancer Screening: Since BPH and prostate cancer share similar symptoms, patients should be evaluated for the presence of prostate cancer before starting Terazosin and at regular intervals thereafter.
• Heart Failure: Terazosin should be used with caution in patients with a history of congestive heart failure, as the fluid retention (edema) caused by the drug may exacerbate the condition.

• Blood Pressure: Regular monitoring of blood pressure, both sitting and standing, is necessary, especially during the titration phase.
• Prostate-Specific Antigen (PSA): While Terazosin does not change PSA levels (unlike 5-alpha reductase inhibitors like Finasteride), regular screenings for prostate health are still required.
• Fluid Balance: Patients should be monitored for signs of edema (swelling) or unexplained weight gain.

Terazosin can cause significant drowsiness and dizziness. Patients should avoid driving, operating heavy machinery, or performing hazardous tasks for at least 24 hours after the first dose, after any dose increase, or if the medication is restarted after a hiatus.

Alcohol can potentiate (increase) the blood pressure-lowering effects of Terazosin. Drinking alcohol while taking this medication significantly increases the risk of dizziness, fainting, and falls. It is strongly recommended to limit or avoid alcohol consumption.

If Terazosin therapy is interrupted for more than a few days, the medication should not be restarted at the previous maintenance dose. Instead, the patient must return to the 1 mg initial dose and undergo the titration process again to prevent severe hypotension.

> Important: Discuss all your medical conditions, including any history of low blood pressure or heart disease, with your healthcare provider before starting Terazosin.

There are few absolute contraindications for drug combinations with Terazosin, but the following require extreme caution:

• Other Alpha-Blockers: Using Terazosin with other alpha-blockers (e.g., Doxazosin, Tamsulosin, Prazosin) is generally avoided due to the high risk of severe, symptomatic hypotension.

• PDE5 Inhibitors (Erectile Dysfunction Drugs): Medications such as Sildenafil (Viagra), Tadalafil (Cialis), and Vardenafil (Levitra) also have vasodilatory effects. When taken with Terazosin, they can cause an additive effect, leading to dangerously low blood pressure. If used together, the patient should be on a stable dose of Terazosin first, and the PDE5 inhibitor should be started at the lowest possible dose.
• Antihypertensives: When Terazosin is added to a regimen of other blood pressure medications (beta-blockers, ACE inhibitors, calcium channel blockers, or diuretics), the risk of hypotension increases. Doctors may need to adjust the dosages of one or both medications.

• NSAIDs (Nonsteroidal Anti-inflammatory Drugs): Drugs like Ibuprofen or Naproxen can cause the body to retain sodium and water, which may counteract the blood pressure-lowering effects of Terazosin.
• Clonidine: Using Terazosin with Clonidine may theoretically decrease the effectiveness of Clonidine, though this is less common in clinical practice.

• Food: There are no significant interactions between Terazosin and specific foods. It can be taken with or without meals. However, staying well-hydrated is important to help prevent dizziness.
• Alcohol: As mentioned, alcohol is a major concern as it relaxes blood vessels further, leading to a high risk of fainting.

• Saw Palmetto: Often used for BPH, Saw Palmetto may have additive effects with Terazosin. While not strictly forbidden, patients should inform their doctor if they are using it.
• St. John's Wort: May potentially affect the metabolism of many drugs, though its specific effect on Terazosin is not well-documented. Monitor for reduced efficacy.
• Garlic/Ginger/Ginkgo: These supplements can have mild blood-thinning or blood pressure-lowering effects, which could theoretically increase the risk of lightheadedness.

Terazosin is not known to significantly interfere with common laboratory tests, including those for blood glucose, cholesterol, or the Prostate-Specific Antigen (PSA) test. Unlike some other BPH medications, Terazosin does not artificially lower PSA levels, making it easier to monitor for prostate cancer.

Interaction Mechanisms

1. 1Pharmacodynamic Additive Effect: Most interactions (like with PDE5 inhibitors) occur because both drugs are trying to relax the same muscles or blood vessels, leading to an exaggerated drop in pressure.
2. 2Fluid Retention: NSAIDs interfere with the kidneys' ability to manage salt, which opposes the 'opening' of blood vessels that Terazosin provides.

> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking, including over-the-counter cold medicines which may contain vasoconstrictors that oppose Terazosin.

Terazosin must NEVER be used in the following circumstances:

• Hypersensitivity: Patients with a known allergy or hypersensitivity to Terazosin Hydrochloride or any of the inactive ingredients in the capsule must not take this drug.
• Cross-Sensitivity: Patients who have had a severe allergic reaction to other quinazoline alpha-blockers (such as Doxazosin or Prazosin) should not take Terazosin, as they are chemically related and cross-reactivity is likely.

These are conditions where the drug should be used only if the benefits clearly outweigh the risks, and under strict medical supervision:

• History of Syncope: If a patient has a history of 'fainting spells,' the use of Terazosin may exacerbate this tendency.
• Severe Hypotension: Patients who already have very low blood pressure may not tolerate the further reduction caused by Terazosin.
• Severe Hepatic Impairment: Since the liver is the primary site of metabolism, severe liver disease can lead to toxic levels of the drug in the bloodstream.
• Cataract Surgery: While not a contraindication to taking the drug long-term, it is a contraindication to starting the drug right before surgery. Surgeons need to be aware of its use to prevent IFIS (Intraoperative Floppy Iris Syndrome).

As mentioned, Terazosin belongs to the quinazoline class. If you have experienced hives, swelling, or difficulty breathing after taking Cardura (Doxazosin) or Minipress (Prazosin), you must notify your doctor, as Terazosin is likely to cause the same reaction.

> Important: Your healthcare provider will evaluate your complete medical history, including any previous reactions to medications, before prescribing Terazosin. Always disclose any history of heart valve disease or liver problems.

Terazosin is classified under FDA Pregnancy Category C. This means that animal reproduction studies have shown an adverse effect on the fetus, but there are no adequate and well-controlled studies in humans.

• Risks: In animal studies, Terazosin was associated with decreased fetal survival.
• Clinical Recommendation: Terazosin should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. It is generally not the first-choice medication for hypertension in pregnant women.

It is not known whether Terazosin is excreted in human milk. Because many drugs are excreted in breast milk and because of the potential for serious adverse reactions in nursing infants (such as significantly low blood pressure), a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.

Terazosin is not approved for use in children. The pathophysiology of hypertension in children often differs from adults, and the safety of alpha-blockade in developing bodies has not been sufficiently studied. Conditions like BPH do not typically occur in the pediatric population.

Patients over the age of 65 represent a significant portion of Terazosin users, particularly for BPH.

• Fall Risk: This population is at a much higher risk for orthostatic hypotension and subsequent falls, which can lead to hip fractures or head injuries.
• Pharmacokinetics: While the half-life is not significantly longer in the elderly, the physiological compensatory mechanisms (like the baroreceptor reflex) are often slower, making the 'first-dose effect' more dangerous.
• Polypharmacy: Elderly patients are more likely to be on other medications (like diuretics or heart meds) that interact with Terazosin.

In patients with impaired renal function, the pharmacokinetics of Terazosin are not significantly altered. The drug is not dialyzable because it is highly protein-bound. No specific dose adjustments are mandated for renal failure, but clinicians should monitor these patients for fluid retention.

Because the liver is the primary organ for Terazosin metabolism, patients with Child-Pugh Class B or C hepatic impairment should be monitored closely. There is no specific formula for dose reduction, but a 'start low, go slow' approach is essential to avoid accumulation and toxicity.

> Important: Special populations require individualized medical assessment. Always inform your doctor if you are pregnant, planning to become pregnant, or are breastfeeding.

Terazosin is a selective antagonist of the alpha-1-adrenoceptor. At the molecular level, it binds to these receptors on the surface of smooth muscle cells. By occupying the receptor, it prevents the endogenous ligand, norepinephrine, from activating the G-protein coupled signaling pathway that leads to an increase in intracellular calcium. Without this calcium influx, the muscle fiber cannot contract, leading to relaxation. In the vasculature, this results in vasodilation. In the prostate gland, it results in the relaxation of the smooth muscle of the prostatic capsule and the bladder neck, reducing the 'dynamic' obstruction of urine.

• Onset of Effect: For hypertension, blood pressure reduction usually begins within 1-2 hours. For BPH, symptomatic improvement may take 2 to 4 weeks of consistent use to become fully apparent.
• Duration: The effects of a single dose last for approximately 24 hours, allowing for once-daily administration.
• Dose-Response: There is a clear dose-response relationship for blood pressure, but for BPH, doses above 10 mg often provide diminishing returns in symptom relief while increasing the risk of side effects.

| Parameter | Value |

|---|---|

| Bioavailability | ~90% |

| Protein Binding | 90% - 94% |

| Half-life | ~12 hours |

| Tmax (Time to peak) | 1 hour |

| Metabolism | Hepatic (Minimal CYP involvement) |

| Excretion | Biliary (60%), Renal (40%) |

• Molecular Formula: C19H25N5O4
• Molecular Weight: 387.43 g/mol (as base), 423.89 g/mol (as HCl salt)
• Solubility: Highly soluble in water and isotonic saline.
• Structure: It is a quinazoline derivative, chemically related to prazosin and doxazosin, but with a longer half-life than prazosin.

Terazosin is classified as a selective alpha-1 adrenergic antagonist. It is part of the 'first-generation' of long-acting alpha-blockers. Unlike Tamsulosin (which is more selective for the alpha-1a subtype found in the prostate), Terazosin is non-subtype selective (affecting 1a, 1b, and 1d), which is why it is effective for both blood pressure and BPH.