Clonidine

What is this medication for?

• Fear-based behavior problems (adjunct); GH-deficiency and pheochromocytoma diagnostics; epidural analgesia adjunct (investigational); premed
• Refractory IBD adjunct (4th-line per Washabau)

How is it given?

Give exactly as your veterinarian prescribed — never change the dose or stop on your own unless your veterinarian has told you to.

What if I miss a dose?

• Give it as soon as you remember — unless it is almost time for the next dose (then skip the missed one; never double up).
• Call your clinic if you miss more than one dose in a row.

Side effects — what should I watch for?

Effects listed as common in this handout

• Sedation (Common)
• Transient hyperglycemia (Diagnostic-dose effect)
• Aggressive behavior (Documented adverse effect)
• Dry mouth, constipation (Class)

Worth a phone call to your veterinarian

• Any new symptom that worries you.

⚠️ Contact your veterinarian or an emergency clinic IMMEDIATELY if you notice

• Hypotension, collapse, unusually slow heart rate (Cardiovascular core effects)

Before starting (or refilling), tell your veterinarian if your pet:

• has or has had: Advanced cardiovascular disease (Perrin contraindication); low blood pressure-prone patients; abrupt withdrawal (rebound high blood pressure — human rule)
• has or has had: Atipamezole / yohimbine reverse alpha2 effects (see atipamezole.md)

• is pregnant, nursing, or used for breeding
• is taking any other medications, supplements, or flea/tick products, including:
  • Mirtazapine
  • Other hypotensives/CNS depressants
  • Tricyclics (human)

Storage and handling

Small tablets (0.1–0.3 mg) — dosing precision matters at microgram/kg scale.

Good to know

• The noradrenergic dimmer-switch for fear: reduces sympathetic arousal (the machinery of panic) rather than GABA-sedating — useful where benzodiazepine disinhibition is unwanted.
• Microgram dosing: 0.01–0.05 mg/kg is a 10–50 micrograms/kg window — decimal-point discipline; a 0.1 mg tablet is already a full small-dog dose.
• Overdose physiology (low blood pressure/unusually slow heart rate) is atipamezole-reversible — the same antidote pair as medetomidine.