Cialis Vs. Terazosin: Drug Comparison

Cialis^® (tadalafil) is used to treat erectile dysfunction (ED) and the symptoms of benign prostatic hyperplasia (BPH). It works by relaxing the muscles of blood vessels and increasing blood flow to particular areas of the body, notably the penis. Cialis is known for its long-lasting effects, allowing for more spontaneity, as it can remain effective for up to 36 hours. It is typically taken as needed, but a lower daily dose option is also available for continuous treatment. Common side effects of Cialis include headaches, indigestion, back pain, and muscle aches, which typically resolve within a few days. It is important to use Cialis with caution, especially for individuals with cardiovascular conditions, and to avoid combining it with nitrates or certain other medications due to the risk of serious interactions.

Terazosin is an oral prescription medication classified as an alpha-1 adrenergic blocker. It is primarily used to treat hypertension (high blood pressure) and benign prostatic hyperplasia (BPH), a condition in which the prostate gland is enlarged and causes urinary symptoms in men. 

By blocking alpha-1 receptors on smooth muscle, terazosin relaxes blood vessels and the muscles in the bladder neck and prostate, allowing for improved blood flow and easier urination. It is not a cure for BPH but helps manage some symptoms caused by the condition, such as difficulty starting urination, weak stream, and the need to urinate frequently or urgently.

Terazosin is typically taken once daily, with doses ranging from 1 milligram (mg) to 20 mg, depending on the condition being treated and the person's response to the medication.

Terazosin’s side effects are generally mild, but can sometimes cause heart palpitations, swelling, or blurred vision, among other symptoms.

Phosphodiesterase-5 (PDE5) inhibitor

Alpha blocker

Cialis (tadalafil) is indicated to treat:

• Erectile dysfunction (ED)

• The signs and symptoms of benign prostatic hyperplasia (BPH)

• ED and the signs and symptoms of BPH (ED/BPH)

Terazosin is indicated:

• For the treatment of symptomatic benign prostatic hyperplasia (BPH)

• For the treatment of hypertension

• Typically taken orally as needed prior to sexual activity, up to once daily (5 mg, 10 mg, and 20 mg doses) OR taken orally once daily (2.5 mg and 5 mg doses)

• Comes in 2.5 mg, 5 mg, 10 mg, and 20 mg tablets

• Typically taken orally once daily

• Comes in 1 mg, 2 mg, 5 mg, and 10 mg capsules

Most common adverse reactions (≥2%) include:

• Headache

• Indigestion

• Back pain

• Muscle pain

• Nasal congestion

• Flushing

• Pain in limb

Adverse reactions during placebo-controlled trials benign prostatic hyperplasia:

• Weakness

• Flu syndrome

• Headache

• Low blood pressure

• Heart fluttering

• Postural low blood pressure

• Fainting

• Nausea

• Peripheral swelling

• Weight gain

• Dizziness

• Somnolence

• Vertigo

• Shortness of breath

• Nasal congestion

• Blurred vision

• Erectile dysfunction

• Urinary tract infection

Adverse reactions during placebo-controlled trials hypertension:

• Weakness

• Back pain

• headache

• Heart fluttering

• Postural low blood pressure

• Fast heart beat

• Nausea

• Swelling

• Peripheral swelling

• Weight gain

• Pain in extremities

• Depression

• Dizziness

• Libido decreased

• Nervousness

• Tingling

• Somnolence

• Shortness of breath

• Nasal congestion

• Inflammation of the sinuses

• Blurred vision

• Erectile dysfunction

• Administration of Cialis to patients using any form of organic nitrate is contraindicated

• History of known serious hypersensitivity reaction to Cialis or Adcirca

• Drug interactions: Nitrates, alpha blockers, antihypertensives, alcohol, CYP3A4 inhibitors (e.g., ketoconazole, ritonavir), CYP3A4 inducers (e.g., rifampin)

• Terazosin is contraindicated in patients known to be hypersensitive to terazosin hydrochloride

• Patients should not use Cialis if sex is inadvisable due to cardiovascular status

• Use of Cialis with alpha blockers, antihypertensives or substantial amounts of alcohol (≥5 units) may lead to low blood pressure

• Cialis is not recommended in combination with alpha blockers for the treatment of BPH, because efficacy of the combination has not been adequately studied and because of the risk of blood pressure lowering

• If taking potent inhibitors of CYP3A4, dose should be adjusted

• Patients should seek emergency treatment if an erection lasts >4 hours

• Patients should stop Cialis and seek medical care if a sudden loss of vision occurs in one or both eyes, which could be a sign of non arteritic ischemic optic neuropathy (NAION)

• Patients should stop Cialis and seek prompt medical attention in the event of sudden decrease or loss of hearing

• Prior to initiating treatment with Cialis for BPH, consideration should be given to other urological conditions that may cause similar symptoms

• Carcinoma of the prostate and BPH cause many of the same symptoms

• Intraoperative floppy iris syndrome (IFIS) has been observed during cataract surgery in some patients on/or previously treated with alpha-1 blockers

• While fainting is the most severe orthostatic effect of terazosin, other symptoms of lowered blood pressure, such as dizziness, lightheadedness and palpitations, were more common and occurred in some 28% of patients in clinical trials of hypertension

• Patients should be made aware of the possibility of fainting and orthostatic symptoms, especially at the initiation of therapy, and to avoid driving or hazardous tasks for 12 hours after the first dose, after a dosage increase and after interruption of therapy when treatment is resumed

• Patients should also be told that drowsiness or somnolence can occur with terazosin, requiring caution in people who must drive or operate heavy machinery

• Patients should be advised about the possibility of priapism as a result of treatment with terazosin and other similar medications

• Small but statistically significant decreases in hematocrit, hemoglobin, white blood cells, total protein and albumin were observed in controlled clinical trials

• Pregnancy: Terazosin is not recommended during pregnancy unless the potential benefit justifies the potential risk to the mother and fetus

• Breastfeeding: Caution should be exercised when terazosin is administered to a nursing woman

*This information is from the label for brand name Cialis^®. See the Full Prescribing Information for more complete information. Tadalafil, the active ingredient in Cialis, may also be the active ingredient in other medications, and this information may not be accurate for all medications that include the active ingredient tadalafil.

*This information is from the terazosin hydrochloride label used by Bionpharma Inc. See the Full Prescribing Information for more complete information. Terazosin hydrochloride may also be the active ingredient in other medications, and this information may not be accurate for all medications that include the active ingredient terazosin hydrochloride.