Product Overview
[Drug name]
Generic name: Terazosin Hydrochloride Tablets
Trade name: Gaoteling
English name: Terazosin Hydrochloride Tablets
Chinese Pinyin: Yansuan Telazooqin Pian
[Ingredients]
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
[Properties] This product is a white tablet or off-white tablet.
[Indications]
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, and can also be used alone when other drugs are not applicable 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) when taken orally.
[Usage and Dosage]
The initial dose for hypertension is 1 mg 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 2-10 mg once a day. No increase in efficacy was observed with doses exceeding 20 mg, and no studies have been conducted on doses above 40 mg. The dosage of benign prostatic hyperplasia (BPH) is adjusted according to the patient's response. The initial dose is 1 mg 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 5-10 mg once a day. Symptoms improved significantly 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, consider reducing the dosage.
[Adverse Reactions]
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, and impotence. Other adverse reactions reported in clinical trials and adverse reactions with unclear relationship 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, rhinitis, cold symptoms, itching, (skin) rash, cough, sweating, visual abnormalities, 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. There have been reports of thrombocytopenia and priapism 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.
[Contraindications]
This product is contraindicated for patients who are allergic to terazosin hydrochloride or its analogs.
[Precautions]
Patients with renal impairment do not need to change the recommended dose; when adding thiazide diuretics or other antihypertensive drugs, the dosage of terazosin should be reduced, and the dosage should be readjusted if necessary. When terazosin is used in combination with thiazide diuretics or other antihypertensive drugs, care should be taken to prevent hypotension. Like other α-adrenaline receptor antagonists, terazosin is not recommended for patients with a history of syncope during urination. The incidence of orthostatic hypotension in patients with prostatic hyperplasia is higher than that in patients with hypertension, and it is more likely to occur in elderly patients than in younger patients. If the medication is interrupted for several days, the initial dose regimen should be used again for treatment. Dizziness, mild headache or drowsiness may occur when the medication is first used or when the medication is stopped or re-administered after discontinuation; it is recommended that driving or hazardous work should be avoided within 12 hours of the initial dose or when the dose is increased. Like other α-adrenaline receptor antagonists, terazosin can also cause dizziness. Dizziness often occurs within 30 to 90 minutes of the initial medication, and occasionally occurs when the dose is increased too quickly or another antihypertensive drug is added. If dizziness occurs, the patient should be placed in a recumbent position and supportive therapy should be used if necessary. Although tachycardia (heart rate 120-160 beats per minute) occasionally occurs before fainting, it is generally believed that syncope is related to excessive orthostatic hypotension. Dizziness, mild headache, and even syncope may occur when turning suddenly from a lying or sitting position to a standing position. When these symptoms occur, the patient should lie down and then sit for a while before standing to prevent the symptoms from recurring. In most cases, this reaction will not occur again after the initial treatment or during the continuous medication phase. Prostate cancer and benign prostatic hyperplasia have many of the same symptoms, and the two may often coexist, so the possibility of prostate cancer should be ruled out before using this product to treat benign prostatic hyperplasia. The use of this product and other similar drug treatments may cause abnormal penile erections. Although this phenomenon is extremely rare, it may lead to permanent impotence if not treated in time. There have been reports of intraoperative floppy iris syndrome (IFIS, a variant of small pupil syndrome) in some patients who are currently or have previously used tamsulosin during cataract surgery. Similar reports have been seen with other α1-blockers, and the possibility of their effects cannot be completely ruled out. During cataract surgery, because IFIS may increase surgical complications, the current or previous use of α1-blockers should be known before ophthalmic surgery.
[Special population medication]
Children's precautions: Not yet clear.
Precautions during pregnancy and lactation: This product is contraindicated in pregnant women, and 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 using this product in the elderly. Elderly patients are more susceptible to orthostatic hypotension than younger patients when using terazosin to treat benign prostatic hyperplasia.
[Drug interactions]
In clinical trials, the proportion of patients who reported dizziness or other adverse reactions in patients treated with this product and 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 if 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 treatment drugs. There are reports that hypotension may occur when this product is used in combination with phosphodiesterase (PDE.5) inhibitors.
[Pharmacological action]
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 combined fraction of LDLc+VLDLc are related to the therapeutic dose of terazosin. In clinical trials, a slight decrease in the plasma concentration of total cholesterol and combined low-density and very low-density lipoproteins after taking terazosin hydrochloride was observed. No increase in total cholesterol was observed when used in combination with other antihypertensive drugs that can increase plasma total cholesterol. Studies have shown that α1-adrenaline receptor antagonism 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-adrenaline 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 showed no potential mutagenicity in the genetic toxicity Ames test, in-vivo cell genetics test, mouse dominant lethal test, in-vivo Chinese hamster chromosome aberration test and V79 cell forward mutation test. 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 human dose) and 5 of 19 male rats in the 120 mg/kg group (960 mg/M2, 80 times the maximum recommended human dose) 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 conceived. Rats given terazosin 40 and 250 mg/kg (29 and 175 times the maximum recommended human dose) orally daily for 1 or 2 years showed a significant increase in testicular atrophy, but this phenomenon was not seen at 8 mg/kg daily (more than 6 times the maximum recommended human dose). Dogs given terazosin 300 mg/kg (more than 500 times the maximum recommended human dose) daily for 3 months also showed testicular atrophy. However, no testicular atrophy was observed after daily administration of 20 mg/kg of terazosin (38 times the maximum recommended human dose) for one 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, without teratogenic effects. Rats were given 480 mg/kg (280 times the maximum recommended human dose) daily and fetal absorption was observed. Rabbits were given 60 times the maximum recommended human dose of terazosin daily, and increased fetal absorption, fetal weight loss, and multiple births were observed. This phenomenon may be a secondary reaction to maternal toxicity. Rats were given 120 mg/kg (75 times the maximum recommended human dose) of terazosin daily, and the number of deaths of pups was significantly increased compared with the control group. Carcinogenic effect Long-term administration of high doses of terazosin to male rats can cause tumor formation, but this phenomenon was not observed in female rats and mice. The relevance of this phenomenon to human clinical medication is not yet known.
[Storage] Shade from light and store in a sealed container.
[Specification] 2mg*14 tablets/plate/box
[Packaging specification] Aluminum-plastic blister packaging. 14 tablets/box.
[Validity period] 60 months
[Approval number] National Medicine Standard H20023659
