ANXIOLYTICS is a topic covered in the Harrison's Manual of Medicine.

To view the entire topic, please or purchase a subscription.

Harrison’s Manual of Medicine 19th edition provides 600+ internal medicine topics in a rapid-access format. Download Harrison’s App to iPhone, iPad, and Android smartphone and tablet. Explore these free sample topics:

Harrison’s Manual of Medicine - App + Web

-- The first section of this topic is shown below --

Benzodiazepines bind to sites on the γ-aminobutyric acid receptor and are cross-tolerant with alcohol and with barbiturates. Four clinical properties: (1) sedative, (2) anxiolytic, (3) skeletal muscle relaxant, and (4) antiepileptic. Individual drugs differ in terms of potency, onset of action, duration of action (related to half-life and presence of active metabolites), and metabolism (Table 197-2). Benzodiazepines have additive effects with alcohol; like alcohol, they can produce tolerance and physiologic dependence, with serious withdrawal syndromes (tremors, seizures, delirium, and autonomic hyperactivity) if discontinued too quickly, especially for those with short half-lives.

NameEquivalent PO Dose, mgOnset of ActionHalf-Life, hComments
 Diazepam (Valium)5Fast20–70Active metabolites; quite sedating
 Flurazepam (Dalmane)15Fast30–100Flurazepam is a prodrug; metabolites are active; quite sedating
 Triazolam (Halcion)0.25Intermediate1.5–5No active metabolites; can induce confusion and delirium, especially in elderly
 Lorazepam (Ativan)1Intermediate10–20No active metabolites, direct hepatic glucuronide conjugation, quite sedating, FDA approved for anxiety with depression
 Alprazolam (Xanax)0.5Intermediate12–15Active metabolites,; not too sedating, FDA approved for panic disorder and anxiety with depression, tolerance and dependence develop easily, difficult to withdraw
 Chlordiazepoxide (Librium)10Intermediate5–30Active metabolites, moderately sedating
 Oxazepam (Serax)15Slow5–15No active metabolites, direct glucuronide conjugation, not too sedating
 Temazepam (Restoril)15Slow9–12No active metabolites, moderately sedating
 Clonazepam (Klonopin)0.5Slow18–50No active metabolites, moderately sedating, FDA approved for panic disorder
 Clorazepate (Tranxene)15Fast40–200Low sedation, unreliable absorption
 Buspirone (BuSpar)7.52 weeks2–3Active metabolites, tid dosing—usual daily dose 10–20 mg tid, nonsedating; no additive effects with alcohol, useful for controlling agitation in demented or brain-injured pts

Buspirone is a nonbenzodiazepine anxiolytic that is nonsedating, is not cross-tolerant with alcohol, and does not induce tolerance or dependence. It requires at least 2 weeks at therapeutic doses to achieve full effects.

-- To view the remaining sections of this topic, please or purchase a subscription --