THERAPEUTICS

Brands

• Catapres, Dixarit, Clorpres, Duraclon (injection only), Kapvay, Jenloga

Generic?

• Yes

Class

• α2-adrenergic agonist

Commonly Prescribed for

(FDA approved in bold)

• Hypertension (immediate release only)

• Attention deficit hyperactivity disorder (ADHD) (extended release only)

• Severe pain in cancer patients

• Postanesthetic shivering

• Withdrawal (alcohol, opiate, methadone)

• Gilles de la Tourette syndrome (GTS), tics

• Smoking cessation

• Growth delay

• Ulcerative colitis

• Menopausal symptoms such as hot flushes

• Neuropathic pain

• Ascites

• Hyperhidrosis

• Anesthesia premedication

• Restless legs syndrome (RLS)

How the Drug Works

• α2 agonist with similar potency at 2A/2B/2C receptors. These adrenergic receptors are distributed throughout the CNS, with α2A and α2C being more in the CNS and α2B more in the periphery (e.g., heart, lung, kidney, liver). Stimulating these presynaptic receptors (α2A, α2C) inhibits norepinephrine release, decreases sympathetic tone, and reduces blood pressure and heart rate. Sedation and analgesia is mediated by centrally located α2A-receptors, while peripheral α2B-receptors mediate vascular constriction. May also reduce plasma renin activity and catecholamine excretion. Additional antihypertensive effect may come from imidazoline I1 receptor agonism

How Long Until It Works

• Hypertension, withdrawal: less than 2 hours

• GTS: weeks to months

• RLS: days

If It Works

• In neurological conditions such as tics, continue to assess effect of the medication and whether it is still needed

If It Doesn't Work

• GTS/tics: neuroleptics are often effective, but their use should be reserved for patients with significant social isolation or embarrassment

• RLS: generally used as an adjunctive agent. Dopamine agonists are more effective

Best Augmenting Combos for Partial Response or Treatment-Resistance

• In hypertension, combine with treatments less likely to affect heart rate or cause orthostasis (ACE inhibitors, diuretics)

• Tics and GTS symptoms may change over time. Many patients improve with age. Behavioral and psychological therapies are useful, and education and reassurance are all that is needed in mild cases

• Identify and treat comorbid conditions such as ADHD or obsessive-compulsive disorder