【醫生信箱】Q64. 小朋友有ADHD及妥瑞症，應否考慮 Clonidine 呢款藥物？
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Q64. 小朋友有ADHD 和妥瑞症，早前政府醫院覆診，專注達藥藥量由18加到27mg ，醫生都關注佢妥瑞症問題，因為見佢抽多左，但又剛巧撞正準備考試嘅溫習周，所以沒法判斷是壓力還是其他原因抽多左，咁醫生都有建議Clonidine呢隻藥，醫生話呢隻藥係可治療adhd 同妥瑞症，但要每星期返醫院覆診一次調較藥量同不可自行停藥，咁其他嘅資料醫生請我自己用AI 去了解下，因為外面太多病人同未決定轉唔轉藥。其實我用 AI 睇完後，除左食藥時間由早變晚及副作用有不同外，都不太明白隻藥點係點幫到小朋友，要返醫院調較幾多次？也不知是否適合我嘅小朋友用藥，如何才是合適或不適合，如果用用下藥發現唔對路可點處理等等，可否請醫生幫忙解釋給我聽🙏🏻 謝謝你
Ans (✍🏻精神科專科醫生 王崇瀚醫生)
被診斷ADHD的兒童 同時出現抽動症狀（突然、重複且非自願的動作或發聲）的情況相當普遍。醫學研究顯示，約30%至50%的ADHD兒童可能同時患有例如妥瑞氏症的慢性抽動障礙。抽動在大壓力或興奮狀態下往往加劇。當兒童同時患有ADHD與抽動症狀時，治療方案必須謹慎選擇以便控制雙重症狀。
Clonidine 屬於α2A-腎上腺素能受體激動劑類藥物，主要集中針對前額葉皮質 （prefrontal cortex）。透過增強此區域的調節能力，可協助控制過動症核心症狀如，增強注意力，增強執行功能，和減少過度活躍與衝動行為。然而證據顯示，傳統ADHD藥物仍是比Clonidine更為有效的選擇。
然而，Clonidine因同時能有效降低抽動頻率與嚴重程度，常被視為一種二線治療的選擇。Clonidine能強化前額葉皮質以抑制抽動症狀，又可藉其鎮靜副作用 減低對中樞神經系統的刺激。此外，Clonidine亦有助改善ADHD患者常見的睡眠問題。
最常見的副作用為鎮靜或嗜睡，因此通常建議夜間服用。其他副作用包括暈眩、血壓或心率下降。因此，服食Clonidine 需定期監測血壓與心率。更重要的是，藥物調校到一段份量時，不可突然停用Clonidine，以避免血壓可能出現反彈性升高。對於家長提問關於較藥的次數：由於每個病人的症狀和對副作用的反應不一樣，調教藥物的次數 和 頻率 是因人而定。
醫學界最近較新的ADHD治療藥物為 Guanfacine。該藥物同樣作用於a2A-腎上腺素受體，因此同時對抽動障礙和ADHD症狀有效。其化學特性有助降低（但無法完全消除）鎮靜與低血壓等不良反應的風險。此外，相比於Clonidine 需每日多次服藥，Guanfacine可採用 once daily dosing。
It is very common for children diagnosed with ADHD to also experience tics (sudden, repetitive, and involuntary movements or vocalizations). Medical research indicates that approximately 30% to 50% of children with ADHD may also have a chronic tic disorder, such as Tourette Syndrome. The symptoms of both conditions are often worse during times of stress or excitement. When a child has both ADHD and tics, treatment must be carefully chosen to manage both sets of symptoms without making either one worse.
Clonidine is a medication that belongs to a class called α2A-adrenergic agonists. Clonidine acts on specific receptors in the prefrontal cortex—the part of the brain responsible for executive functions, attention, and impulse control. By boosting the regulatory power of this area, it can help manage core ADHD symptoms like hyperactivity and impulsivity. However, evidence shows that traditional stimulant medications remain the more efficacious option.
Clonidine is often considered an alternative because it is also effective at reducing the frequency and severity of tics. It accomplishes this by both strengthening the prefrontal cortex which can inhibit tics, and also by calming the central nervous system due to its sedative side effect. In addition, evidence also suggests that clonidine can help with sleep disturbances which is common in ADHD.
The most frequent side effect is sedation or drowsiness, which is why it is often prescribed to be taken at night. Other common issues include dizziness and a drop in blood pressure or heart rate. Because clonidine affects the cardiovascular system, there is a need for regular monitoring of their blood pressure and heart rate. It is also essential that clonidine is never stopped abruptly; it must be gradually reduced (tapered) under medical supervision to avoid a potential rebound increase in blood pressure.
A more recent ADHD treatment would be Guanfacine. It targets the same a2A-adrenergic receptors and is thus effective as an option for patients with ADHD and comorbid tics disorder. Its more selective profile helps reduce, but not eliminate the risk of unwanted side effects like sedation and hypotension. Guanfacine often allows for once-daily dosing, which can be more convenient and simplify adherence compared to the multiple daily dosing typically required for clonidine.