Side effects of clonidine
Pro Research Analysisby 
Searched over 200M research papers
Side Effects of Clonidine: A Comprehensive Overview
Introduction to Clonidine and Its Uses
Clonidine is a medication primarily used to treat high blood pressure, but it has also found applications in managing withdrawal symptoms, pain relief, ADHD, and smoking cessation. Despite its effectiveness, clonidine is associated with a range of side effects that can impact patient compliance and quality of life.
Common Side Effects: Sedation and Dry Mouth
Sedation
Sedation is one of the most frequently reported side effects of clonidine. In a study involving healthy subjects, all participants experienced severe sedation after a single oral dose of clonidine1. This sedative effect was also observed in patients with postherpetic neuralgia, where 74% of those treated with clonidine reported sedation2. Additionally, sedation was noted in patients receiving intrathecal clonidine for postoperative analgesia8.
Dry Mouth
Dry mouth is another prevalent side effect. In the same study with healthy subjects, a significant correlation was found between clonidine plasma concentrations and the occurrence of dry mouth1. This side effect was also prominent in trials for smoking cessation, where a high incidence of dry mouth was reported5.
Cardiovascular Side Effects: Hypotension and Bradycardia
Hypotension
Clonidine can cause hypotension, particularly when administered intrathecally. A dose-response study showed that higher doses of intrathecal clonidine led to significant reductions in mean arterial pressure8. Similarly, oral clonidine premedication was found to attenuate hemodynamic changes during ketamine anesthesia, reducing mean arterial pressure9.
Bradycardia
Bradycardia, or a slower than normal heart rate, is another cardiovascular side effect associated with clonidine. This was observed in patients receiving intrathecal clonidine, where bradycardia was noted alongside hypotension and sedation8.
Neurological and Psychological Side Effects
Dizziness
Dizziness is a common side effect, particularly in patients using clonidine for pain relief. In a study on postherpetic neuralgia, dizziness was frequently reported by patients treated with clonidine2. This side effect can significantly impact daily activities and overall well-being.
Nightmares
Nightmares have been reported as a side effect of clonidine, particularly when used as premedication for anesthesia. A study found that patients who received higher doses of clonidine experienced fewer nightmares compared to those who received a placebo9.
Side Effects in Specific Populations
ADHD Treatment
In children and adolescents with ADHD, clonidine has been associated with several side effects. A meta-analysis revealed that while clonidine is effective in managing ADHD symptoms, it is linked to many side effects, including sedation and dizziness6. Another study found that clonidine, when added to psychostimulant therapy, caused transient sedation and dizziness in children7.
Alcohol Withdrawal
Interestingly, in the context of alcohol withdrawal, clonidine did not show significant side effects. A study found that patients recovering from alcohol withdrawal experienced no significant side effects when treated with clonidine4.
Conclusion
Clonidine is a versatile medication with a range of therapeutic applications. However, its use is often accompanied by side effects such as sedation, dry mouth, hypotension, bradycardia, dizziness, and nightmares. These side effects can vary in severity and impact depending on the dosage and the specific condition being treated. Understanding these side effects is crucial for healthcare providers to manage and mitigate them effectively, ensuring better patient outcomes.
Sources and full results
Most relevant research papers on this topic
Pharmacokinetics and side-effects of clonidine
Clonidine has a short half-life and sedation and dry mouth side-effects are common, with a peak at about 2 hours after a single oral dose.
Non-RCTAssociation of pain relief with drug side effects in postherpetic neuralgia: A single‐dose study of clonidine, codeine, ibuprofen, and placebo
Clonidine provides more pain relief than codeine and ibuprofen, but has more side effects, suggesting a specific analgesic effect.
RCT
Highly CitedHypotensive Action and Side Effects of Clonidine-Chlorthalidone and Methyldopa-Chlorthalidone in Treatment of Hypertension
Clonidine-chlorthalidone effectively reduces diastolic morning blood pressure in more patients than methyldopa-chlorthalidone, but side effects are more common with clonidine.
RCTCLONIDINE IN ALCOHOL WITHDRAWAL
Clonidine effectively reduces alcohol withdrawal symptoms and improves general condition without significant side effects.
RCTHighly CitedClonidine for smoking cessation.
Clonidine is effective in promoting smoking cessation, but its side-effects, particularly dry mouth and sedation, limit its usefulness.
Meta-AnalysisHighly CitedA meta-analysis of clonidine for symptoms of attention-deficit hyperactivity disorder.
Clonidine may be an effective second-tier treatment for ADHD symptoms, but has a smaller effect size than stimulants and is associated with many side effects.
Meta-AnalysisHighly CitedA randomized controlled trial of clonidine added to psychostimulant medication for hyperactive and aggressive children.
Clonidine combined with psychostimulant medication effectively reduces conduct symptoms in children with attention-deficit/hyperactivity disorder, with well-tolerated treatment and transient side effects.
RCTHighly CitedHemodynamic and Analgesic Profile after Intrathecal Clonidine in Humans: A Dose-Response Study
Intrathecal clonidine effectively reduces pain after surgery, with doses up to 450 g providing nearly immediate relief without causing hypotension or bradycardia.
Highly CitedEffects of oral clonidine premedication on side effects of intravenous ketamine anesthesia: a randomized, double-blind, placebo-controlled study.
Oral clonidine premedication reduces cardiostimulatory effects and reduces the incidence and severity of nightmares and salivation during intravenous ketamine anesthesia.
RCTAntihypertensive Effect of Clonidine
Clonidine hydrochloride effectively reduces blood pressure in patients with essential hypertension, but may cause drowsiness and dry mouth at higher doses.
Highly Cited