Terazosin Hydrochloride Tablets

Pharmacological action: This product is a selective α1 receptor blocker that can reduce peripheral vascular resistance and has a lowering effect on both systolic and diastolic blood pressure. It has the effect of relaxing bladder and prostate smooth muscles and can relieve the symptoms of dysuria caused by benign prostatic hypertrophy. [1] Although the exact mechanism of the antihypertensive effect of terazosin hydrochloride has not been established so far, the relaxation of peripheral blood vessels is mainly caused by the competitive antagonism of postsynaptic α-adrenaline receptors. Terazosin initially produces a slow blood pressure-lowering effect and then exerts a sustained antihypertensive effect. Clinical experience shows that a 2-5% reduction in plasma total cholesterol and a 3-7% reduction in the LDLcVLDLc binding fraction are related to the therapeutic dose of terazosin. In clinical trials, a slight decrease in the plasma concentration of total cholesterol and bound low-density and very low-density lipoproteins was observed after taking terazosin hydrochloride. No increase in total cholesterol was observed when combined with other antihypertensive drugs that can increase plasma total cholesterol. Studies have shown that the antagonism of α1 adrenaline receptors is beneficial for improving urethral function in patients with chronic bladder obstruction (such as benign prostatic hyperplasia, BPH). BPH symptoms are mainly caused by prostatic hyperplasia and increased thresholds of urethral outlet and prostatic smooth muscle (mainly regulated by α1 adrenergic receptors). In vitro tests have shown that terazosin hydrochloride can antagonize the contraction of human prostate tissue induced by phenylephrine. Clinical trials have also shown that terazosin hydrochloride can improve urethral function and symptoms in patients with BPH. Toxicity studies Ames test for genetic toxicity, in-vivo cell genetics test, dominant lethal test in mice, in-vivo Chinese hamster chromosome aberration test and V79 cell forward mutation test all showed no potential mutagenicity. Reproductive toxicity Rats were gavaged daily with 8, 30 and 120 mg/kg terazosin to study the effects on fertility/reproduction. The results showed that 4 of 20 male rats in the 30 mg/kg group (240 mg/M2, 20 times the maximum recommended dose for humans) and 5 of 19 male rats in the 120 mg/kg group (960 mg/M2, 80 times the maximum recommended dose for humans) lost their fertility. The weight and shape of the testicles were not affected. Vaginal smears after mating showed that the sperm count in the 30 and 120 mg/kg groups was lower than that in the control group, and the sperm count was well correlated with the number of fetuses. Rats given 40 and 250 mg/kg of terazosin (29 and 175 times the maximum recommended human dose) orally for 1 or 2 years showed a significant increase in testicular atrophy, but this phenomenon was not seen with 8 mg/kg per day (6 times the maximum recommended human dose). Dogs given 300 mg/kg of terazosin (500 times the maximum recommended human dose) per day for 3 months also showed testicular atrophy. However, no testicular atrophy was seen with 20 mg/kg of terazosin (38 times the maximum recommended human dose) per day for 1 year. Prazosin (a selective α1 receptor blocker) can also cause this damage. Rats and rabbits were given terazosin orally at 280 and 60 times the maximum recommended human dose, respectively, and no teratogenic effects were observed. Rats given 480 mg/kg per day (280 times the maximum recommended human dose) showed fetal absorption. When rabbits were given terazosin at 60 times the maximum recommended human dose per day, increased fetal absorption, reduced fetal weight, and multiple births were observed in the offspring. This phenomenon may be a secondary reaction to maternal toxicity. When rats were given 120 mg/kg (75 times greater than the maximum recommended human dose) of terazosin per day, the number of deaths in the pups increased significantly compared with the control group. Carcinogenicity Long-term administration of high doses of terazosin to male rats can cause tumor formation, but this phenomenon has not been observed in female rats and mice. The relevance of this phenomenon to human clinical medication is not yet known.

The main ingredient of this product is: terazosin hydrochloride. Its chemical name is: 1-(4-amino-6,7-dimethoxy-2-quinazolinyl)-4-(tetrahydrofuran-2-formyl)piperazine, monohydrochloride dihydrate. Molecular formula: C19H25N5O4·HCl·2H2O Molecular weight: 459.93

This product is white or off-white tablets.

This product is suitable for the treatment of mild or moderate hypertension when taken orally. It can be used in combination with thiazide diuretics or other antihypertensive drugs. It can also be used alone when other drugs are not suitable or ineffective. This product mainly reduces diastolic blood pressure. This product is also suitable for the treatment of symptoms caused by benign prostatic hyperplasia (BPH).

The initial dose for hypertension is 1 mg taken before bedtime, and should not be exceeded to minimize the occurrence of hypotension events with the first dose. After one week, the daily single dose can be doubled to achieve the expected effect. The commonly used maintenance dose is 2 to 10 mg once a day. No increase in efficacy has been observed with doses exceeding 20 mg, and no studies have been conducted on doses above 40 mg. The dosage for benign prostatic hyperplasia (BPH) is adjusted according to the patient's response. The initial dose is 1 mg taken before bedtime, and should not be exceeded to minimize the occurrence of hypotension events with the first dose. After one or two weeks, the daily dose can be doubled to achieve the expected effect. The commonly used maintenance dose is 5 to 10 mg once a day. Symptoms are significantly improved after two weeks of administration. So far, there is not enough data to show that doses exceeding 10 mg once a day will cause further symptom relief. Treatment should be started with the initial dose and the efficacy summary should be conducted after four weeks. Temporary adverse reactions may occur with each dose adjustment. If adverse reactions persist, a dose reduction should be considered.

The most common ones are: weakness, palpitations, nausea, peripheral edema, dizziness, drowsiness, nasal congestion/rhinitis and blurred vision/amblyopia. In addition, the following adverse reactions have also been reported: back pain, headache, tachycardia, postural hypotension, syncope, edema, weight gain, extremity pain, decreased libido, depression, nervousness, paresthesia, dyspnea, sinusitis, impotence. Other adverse reactions reported in clinical trials and adverse reactions that are not clearly related to the use of this product in market feedback reports: chest pain, facial edema, fever, abdominal pain, neck pain, shoulder pain, vasodilation, arrhythmia, constipation, diarrhea, dry mouth, dyspepsia, flatulence, vomiting, gout, arthralgia, arthritis, joint disorders, myalgia, anxiety, insomnia, bronchitis, epistaxis, flu symptoms, pharyngitis, rash, cough, sweating, abnormal vision, conjunctivitis, tinnitus, frequent urination, urinary tract infection and early urinary incontinence in postmenopausal women. At least two cases of allergic reactions have been reported with the use of this product. Thrombocytopenia and priapism have been reported with the use of this product, and atrial fibrillation has also been reported; however, a causal relationship has not yet been established. Laboratory tests: In clinical controlled trials, a small but statistically significant decrease in hematocrit, hemoglobin, white blood cells, total protein, and albumin was found. These laboratory results indicate the possibility of plasma dilution. Continuous use of this product for more than 24 months has no significant effect on prostate-specific antigen (PSA) levels.

This product is contraindicated for patients who are allergic to terazosin hydrochloride or its analogs.

Precautions for children: Not clear. Precautions for pregnancy and lactation: Pregnant women are prohibited from using this product. Lactating women should stop breastfeeding when using this product. Precautions for the elderly: Pharmacokinetic studies have shown that the recommended dose does not need to be changed when the elderly use this product. Elderly patients are more likely to develop orthostatic hypotension than younger patients when using terazosin to treat benign prostatic hyperplasia.

In clinical trials, the proportion of patients who reported dizziness or other adverse reactions in patients who were treated with this product in combination with angiotensin (ACE) preparations or diuretics was higher than the proportion of all patients treated with this product. When this product is used in combination with other antihypertensive drugs, it should be observed carefully to avoid significant hypotension. When this product is added to diuretics or other antihypertensive drugs, the dose should be appropriately reduced and re-established when necessary. It is known that this product will not interact with analgesics/anti-inflammatory drugs, cardiac glycosides, hypoglycemic drugs, antiarrhythmic drugs, antianxiety drugs/sedatives, antibacterial drugs, hormones/steroids and gout drugs. There are reports that hypotension may occur when this product is used in combination with phosphodiesterase (PDE.5) inhibitors.

Keep away from light and store in sealed container.

2mg*14 tablets/plate/box

60 months

Shanghai Abbott Pharmaceutical Co., Ltd.

• Founded in:

  1998-01-25

• Address:

  No. 1288, Wusi Road, Haiwan Town, Fengxian District, Shanghai

• Tax NO.:

  91310000607386069E

• Registered Funds:

  $8 million

• Email:

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