Clonidine Toxicity

**Potential indications for use: Hypertension, ADHD, peripheral nerve and spinal anesthesia, management of opioid, ETOH or nicotine withdrawal

**Pharmacology: centrally alpha2-adrenergic receptor agonism

--enhances activity of inhibitory neurons in CNS vasoregulatory regions → decrease sympathetic outflow → reduces heart rate, vascular tone and arterial blood pressure

**Pharmacokinetics: absorbed by GI tract, excreted via kidneys, onset of action 30-60 minutes, peak serum concentration 2-3 hours, effects can 8+ hours

**Formulations: oral, patch

--Note puncturing patch outer membrane layer or backing causes significant amount of drug to be release rapidly

**Clinical symptoms:

--within 30-90 minutes - CNS depression, bradycardia, hypotension, hypothermia

--Respirations slow and shallow, intermittent deep breaths, gasping, periodic apnea

--miotic pupils

**Management: symptomatic support

--continuous cardiac and Pox monitoring

--EKG and accucheck

--Respiratory apnea and/or hypoxia - stimulation often arouses patient; mechanical ventilation

--Hypotension - IVF 20cc/kg in peds, 500-1000mL in adults

--Symptomatic bradycardia (signs of decreased perfusion) - atropine

--Naloxone- high doses (4-10mg), if response start infusion

Reference:

Francis JD. Miscellaneous Antihypertensives and Pharmacological Related Agents. In: Hoffman RS, Howland M, Lewin NA, Nelson LS, Goldfrank LR. eds.Goldfrank's Toxicologic Emergencies, 10e New York, NY: McGraw-Hill; 2015