Jerie P
Br J Clin Pharmacol. 1980;10 Suppl 1(Suppl 1):157S-164S. doi: 10.1111/j.1365-2125.1980.tb04924.x.
In 580 hypertensive patients treated with guanfacine for one year and 169 patients who continued the treatment for a second year, laboratory measurements were made before, during and after the end of treatment. Side-effects were registered every month. On completion of the one and two-year studies respectively, therapy was discontinued and blood pressure, heart rate and side-effects were recorded in order to assess the frequency of a withdrawal syndrome. No impairment of laboratory values was seen during long-term treatment. There was no retention of sodium, chloride and water, and no potassium depletion. Guanfacine did not interfere with carbohydrate metabolism during the long-term treatment, and there was no deterioration of clinical diabetes. The overall frequencies of dryness of the mouth and sedation were 60 and 33%, respectively. At the end of one year of treatment these figures dropped to 15 and 5.7%. Further untoward reactions in the first and second year, respectively, were orthostatic disturbances (15 and 6.5%), constipation (14 and 4.1%), male sexual dysfunction (4.6 and 0.6%), insomnia (5.5 and 2.2%), and sweating (5.3 and 1.7%). The frequency and severity of side-effects were dose dependent and related to increases in dosage. Doses of 2 mg and lower caused practically no dryness of the mouth. A withdrawal syndrome occurred in about 3% of patients after discontinuation of prolonged treatment. It was seen in patients with a history of very high blood pressure readings, who showed a tendency to tachycardia and who had been treated with divided doses of guanfacine exceeding 4 mg daily. Only patients with clinical symptoms of increased sympathetic activity were considered to have a withdrawal syndrome (or `phenomenon'). No signs of tachyphylaxis or habituation (tolerance) were seen during the long-term treatment with guanfacine.
在580例接受胍法辛治疗一年的高血压患者以及169例继续接受第二年治疗的患者中，在治疗前、治疗期间以及治疗结束后均进行了实验室测量。每月记录副作用情况。在分别完成一年和两年的研究后，停止治疗，并记录血压、心率和副作用，以评估撤药综合征的发生率。长期治疗期间未发现实验室指标受损。没有钠、氯和水潴留，也没有钾缺乏。胍法辛在长期治疗期间不干扰碳水化合物代谢，临床糖尿病也没有恶化。口干和镇静的总体发生率分别为60%和33%。治疗一年结束时，这些数字降至15%和5.7%。第一年和第二年分别出现的其他不良反应有体位性障碍（15%和6.5%）、便秘（14%和4.1%）、男性性功能障碍（4.6%和0.6%）、失眠（5.5%和2.2%）以及出汗（5.3%和1.7%）。副作用的频率和严重程度与剂量有关，且随剂量增加而增加。2毫克及以下剂量几乎不会引起口干。长期治疗停药后，约3%的患者出现撤药综合征。在有极高血压读数病史、有心动过速倾向且每日服用胍法辛分剂量超过4毫克的患者中可见到。只有具有交感神经活动增强临床症状的患者才被认为有撤药综合征（或“现象”）。在胍法辛的长期治疗期间未观察到快速耐受性或习惯性（耐受性）的迹象。
