944
Chapter 29: Psychopharmacological Treatment
Doses of 100 mg have not been shown to be superior to doses
of 50 mg, but they produce more anticholinergic effects than
doses of 50 mg.
Hydroxyzine is most commonly used as a short-term anxio-
lytic. Hydroxyzine should not be given IV because it is irritating
to the blood vessels. Dosages of 50 to 100 mg given orally four
times a day for long-term treatment or 50 to 100 mg IM every 4
to 6 hours for short-term treatment are usually effective.
SSRI-induced anorgasmia may sometimes be reversed
with 4 to 16 mg a day of cyproheptadine taken by mouth 1 or
2 hours before anticipated sexual activity. A number of case
reports and small studies have also reported that cyprohepta-
dine may be of some use in the treatment of eating disorders,
such as anorexia nervosa. Cyproheptadine is available in 4 mg
tablets and a 2 mg/5 mL solution. Children and elderly patients
are more sensitive to the effects of antihistamines than are
young adults.
R
eferences
Armstrong SC, Cozza KL. Antihistamines.
Psychosomatics.
2003;44(5):430.
Brown RE, Stevens DR, Haas HL. The physiology of brain histamine.
Prog Neu-
robiol.
2001;63(6):637.
Camelo-Nunes IC. New antihistamines: A critical view.
J Pediatr (Rio J).
2006;
82[5 Suppl]:S173.
Davies AJ, Harindra V, McEwan A. Cardiotoxic effect with convulsions in terfena-
dine overdose.
BMJ.
1989;298(6669):325.
Haas H, Panula P. The role of histamine and the tuberomammillary nucleus in the
nervous system.
Nat Rev Neurosci.
2003;4(2):121.
Linnet K, Ejsing TB. A review on the impact of P-glycoprotein on the penetration
of drugs into the brain. Focus on psychotropic drugs.
Eur Neuropsychopharma-
col.
2008;18(3):157.
McIntyre RS. Antihistamines. In: Sadock BJ, Sadock VA, Ruiz P, eds.
Kaplan &
Sadock’s Comprehensive Textbook of Psychiatry.
9
th
ed. Vol. 2. Philadelphia:
Lippincott Williams & Wilkins; 2009:3033.
Table 29.7-3
Dosage and Administration of Common Histamine Antagonists
Medication
Route
Preparation
Common Dosage
Diphenhydramine
(Benadryl)
PO
Capsules and tablets: 25 mg, 50 mg
Adults: 25–50 mg three to four times per day
Liquid: 12.5 mg/5.0 mL
Children: 5 mg/kg three to four times per day, not to
exceed 300 mg/day
Deep IM or IV Solution: 10 or 50 mg/mL
Same as oral
Hydroxyzine
Hydrochloride
(Atarax)
PO
Tablets: 10, 25, 50, and 100 mg
Adults: 50–100 mg three to four times daily
Syrup: 10 mg/5 mL
Children younger than 6 yrs of age: 2 mg/kg/day in
divided doses
Children older than 6 yrs of age: 12.5–25.0 mg three
to four times daily
IM
Solution: 25 or 50 mg/mL
Same as oral
Pamoate (Vistaril)
PO
Suspension: 25 mg/mL
Same as dosages for hydrochloride
Capsules: 25, 50, and 100 mg
Promethazine
(Phenergan)
PO
Tablets: 15.2, 25.0, and 50.0 mg
Adults: 50–100 mg three to four times daily for
sedation
Syrup: 3.25 mg/5 mL
Children: 12.5–25.0 mg at night for sedation
Rectal
Suppositories: 12.5, 25.0, and 50.0 mg
IM
Solution: 25 and 50 mg/mL
Cyproheptadine
(Periactin)
PO
Tablets: 4 mg
Adults: 4–20 mg/day
Syrup: 2 mg/5 mL
Children 2–7 yr of age: 2 mg two to three times daily
(maximum, 12 mg/day)
Children 7–14 yrs of age: 4 mg two to three times
daily (maximum of 16 mg/day)
IM, intramuscular; IV, intravenous; PO, oral.
Montoro J, Sastre J, Bartra J, del Cuvillo A, Davila I. Effect of H
1
antihistamines
upon the central nervous system.
J Investig Allergol Clin Immunol.
2006;
16[Suppl 1]:24.
Shapiro BJ, Lynch KL, Toochinda T, Lutnick A, Cheng HY, Kral AH. Prometha-
zine misuse among methadone maintenance patients and community-based
injection drug users.
J Addict Med.
2013;7(2):96–101.
Simons FE. Advances in H
1
-antihistamines.
N Engl J Med.
2004;351(21):2203.
Theunissen EL, Vermeeren A, Vuurman EF, Ramaekers JG. Stimulating effects of
H
1
-antagonists.
Curr Pharm Des.
2006;12(20):2501.
Welch MJ, Meltzer EO, Simons FE. H
1
-antihistamines and the central nervous
system.
Clin Allergy Immunol.
2002;17:337.
Yanai K, Tashiro M. The physiological and pathophysiological roles of neuronal
histamine: An insight from human positron emission tomography studies.
Phar-
macol Ther.
2007;113(1):1.
▲▲
29.8 Barbiturates and
Similarly Acting Drugs
The first barbiturate to be used in medicine was barbital (Vero-
nal), which was introduced in 1903. It was followed by phe-
nobarbital (Luminal), amobarbital (Amytal), pentobarbital
(Nembutal), secobarbital (Seconal), and thiopental (Pentothal).
Many others have been synthesized, but only a handful has been
used clinically (Table 29.8-1). Many problems are associated
with these drugs, including high abuse and addiction potential, a
narrow therapeutic range with low therapeutic index, and unfa-
vorable side effects. The use of barbiturates and similar com-
pounds such as meprobamate (Miltown) has practically been
eliminated by the benzodiazepines and hypnotics, such as zol-
pidem (Ambien), eszopiclone (Lunesta), and zaleplon (Sonata),
which have a lower abuse potential and a higher therapeutic
index than the barbiturates. Nevertheless, the barbiturates still
