Yohimbine (Systemic)


VA CLASSIFICATION
Primary: CV150
Secondary: GU900; OP900

Commonly used brand name(s): Actibine; Aphrodyne; Baron-X; Dayto Himbin; PMS-Yohimbine; Prohim; Thybine; Yocon; Yohimar; Yohimex; Yoman; Yovital.

Note: For a listing of dosage forms and brand names by country availability, see Dosage Forms section(s).



Category:


Impotence therapy agent —

mydriatic—

sympatholytic—

Indications

Note: Bracketed information in the Indications section refers to uses that are not included in U.S. product labeling.

Accepted

[Impotence (treatment)]1—Yohimbine is used in the treatment of erectile impotence. {01} {02} {06} {07} {08} {09} {10} {11}

Mydriatic agent—Yohimbine is indicated as a mydriatic agent.{02}

Sympathicolytic agent—Yohimbine is also indicated as a sympatholytic agent, which acts as a vasodilator to increase peripheral blood flow.{02}

1 Not included in Canadian product labeling.



Pharmacology/Pharmacokinetics

Physicochemical characteristics:

pKa—
    7.13 {03}

Mechanism of action/Effect:

Yohimbine is a pre-synaptic alpha 2-adrenergic blocking agent. {01} {02} {04} The exact mechanism for its use in impotence has not been fully elucidated. {06} {08} {09} However, yohimbine may exert its beneficial effect on erectile ability through blockade of central alpha 2-adrenergic receptors producing an increase in sympathetic drive secondary to an increase in norepinephrine release and in firing rate of cells in the brain noradrenergic nuclei. {07} Yohimbine-mediated norepinephrine release at the level of the corporeal tissues may also be involved. In addition, beneficial effects may involve other neurotransmitters such as dopamine and serotonin and cholinergic receptors. {08}


Other actions/effects:

Yohimbine exerts a stimulant effect on mood {01} {02} and may increase blood pressure at higher doses. {12} {14} Yohimbine may also have mild antidiuretic action, possibly due to release of antidiuretic hormone. {01} {02} {15}

Absorption:

Rapid {05}; bioavailability is highly variable, ranging from 7 to 87% (mean 33%) {13}; absorption is generally complete within 45 to 60 minutes. {05}

Biotransformation:

Yohimbine appears to undergo extensive metabolism in an organ of high flow such as the liver or kidney {05}; however, the precise metabolic fate of yohimbine has not been fully determined. {13}

Half-life:

Elimination half-life is approximately 36 minutes {05} {13}.

Onset of action:

Approximately 2 to 3 weeks for onset of therapeutic effect. {08} {09} {10}

Elimination:
    Renal, less than 1% as unchanged drug. {05}


Precautions to Consider

Cross-sensitivity and/or related problems

Patients sensitive to rauwolfia alkaloids such as deserpidine, rauwolfia serpentina, or reserpine may also be sensitive to yohimbine.

Geriatrics


Although appropriate studies on the relationship of age to the effects of yohimbine have not been performed in the geriatric population, some studies have included a small number of patients 65 years of age and older and have not demonstrated geriatrics-specific problems that would limit the usefulness of yohimbine in the elderly.

Drug interactions and/or related problems
The following drug interactions and/or related problems have been selected on the basis of their potential clinical significance (possible mechanism in parentheses where appropriate)—not necessarily inclusive (» = major clinical significance):


Note: Combinations containing any of the following medications, depending on the amount present, may also interact with this medication.

Antidepressants{01}{02} or
Mood-modifying medications, other{01}{02}    (yohimbine may antagonize the effects of these agents when used concurrently)


Antihypertensive agents    (yohimbine may antagonize the antihypertensive effects of these agents when used concurrently)


Medical considerations/Contraindications
The medical considerations/contraindications included have been selected on the basis of their potential clinical significance (reasons given in parentheses where appropriate)— not necessarily inclusive (» = major clinical significance).


Except under special circumstances, this medication should not be used when the following medical problems exist:
» Angina pectoris or{01}{02}
» Cardiac disease or
» Hypertension    (may be aggravated)


» Renal function impairment{01}{02}{15}    (yohimbine may worsen this condition)


Risk-benefit should be considered when the following medical problems exist
Depression or
Psychiatric illness, other{01}{02}    (yohimbine may enhance anxiety or other CNS symptoms)


Hepatic function impairment{18}    (although not fully determined, may interfere with biotransformation of yohimbine)


Sensitivity to yohimbine

Patient monitoring
The following may be especially important in patient monitoring (other tests may be warranted in some patients, depending on condition; » = major clinical significance):

Blood pressure and
Heart rate measurements    (periodically during the course of therapy)




Side/Adverse Effects
The following side/adverse effects have been selected on the basis of their potential clinical significance (possible signs and symptoms in parentheses where appropriate)—not necessarily inclusive:

Those indicating need for medical attention
Incidence less frequent
    
Increased blood pressure{01}{02}
    
increased heart rate{01}{02}



Those indicating need for medical attention only if they continue or are bothersome
Incidence less frequent
    
Dizziness{01}{02}{11}
    
headache{01}{02}{08}
    
irritability{01}{02}
    
nervousness or restlessness{07}{11}

Incidence rare
    
Nausea or vomiting{01}{02}{11}
    
skin flushing{01}{02}
    
sweating{01}{02}
    
tremor{01}{02}





Patient Consultation
As an aid to patient consultation, refer to Advice for the Patient, Yohimbine (Systemic) .

In providing consultation, consider emphasizing the following selected information (» = major clinical significance):

Before using this medication
»   Conditions affecting use, especially:
Sensitivity to yohimbine or rauwolfia alkaloids such as deserpidine, rauwolfia serpentina, or reserpine
Other medical problems, especially angina pectoris, cardiac disease, hypertension, or renal function impairment

Proper use of this medication
May require 2 to 3 weeks before beneficial effects are evident

» Proper dosing
Missed dose: Taking as soon as possible if remembered within 4 hours; not taking if remembered later; not doubling doses

» Proper storage

Precautions while using this medication
Regular visits to physician to check progress

Compliance with therapy; importance of not exceeding prescribed dosage


Side/adverse effects
Signs of potential side effects, especially increased blood pressure and increased heart rate


General Dosing Information
Patients receiving yohimbine should be under the supervision of a physician experienced in its use.


Oral Dosage Forms

Note: Bracketed uses in the Dosage Forms section refer to categories of use and/or indications that are not included in U.S. product labeling.

YOHIMBINE HYDROCHLORIDE TABLETS

Usual adult dose
[Impotence]1
Oral, 5.4 to 6 mg three times a day.


Note: If side effects occur, dosage may be reduced in half, followed by gradual increases.
A dose of 10 mg three times a day may be appropriate in some patients; however, the incidence of side effects may be increased. {20}


Strength(s) usually available
U.S.—


2.2 mg (Rx)[Generic]{24}


5 mg (Rx) [Actibine][Generic]{21}


5.4 mg (Rx) [Aphrodyne (scored){32}] [Baron-X{22}] [Dayto Himbin (scored){23}{30}] [Prohim (scored){31}] [Thybine{27}{29}] [Yocon] [Yohimar{21}{28}] [Yohimex] [Yoman{24}] [Yovital{24}][Generic]

Canada—


2 mg (Rx) [PMS-Yohimbine{25}][Generic] (may be scored){16}{26}


5.4 mg (Rx) [Yocon][Generic] (may be scored){16}{17}{26}


6 mg (Rx) [PMS-Yohimbine{25}][Generic]{16}

Packaging and storage:
Store below 40 °C (104 °F), preferably between 15 and 30 °C (59 and 86 °F), unless otherwise specified by manufacturer.



Revised: 6/28/2000



References
  1. Aphrodyne package insert (Star —US), Rec 4/92.
  1. Yocon package insert (Palisades—US), Rev 1/85, Rec 4/92.
  1. Lambert GA, Lang WJ, Friedman E, Meller E, Gershon S. Pharmacological and biochemical properties of isomeric yohimbine alkaloids. Eur J Pharmacol 1978; 49: 39-48.
  1. Hoffman BB, Lefkowitz RJ. Adrenergic receptor antagonists. In: Goodman Gilman A, Rall TW, Nies AS, Taylor P, eds. The pharmacological basis of therapeutics, 8th ed. New York: Pergamon Press, Inc. 1990; 229.
  1. Owen JA, Nakatsu SL, Fenemore J, Condra M, Surridge DH, Morales A. The pharmacokinetics of yohimbine in man. Eur J Clin Pharmacol 1987; 32: 577-82.
  1. Sonda LP, Mazo R, Chancellor MB. The role of yohimbine for the treatment of erectile impotence. J Sex and Marital Ther 1990; 16(1): 15-21.
  1. Riley AJ, Goodman RE, Kellett JM, Orr R. Double blind trial of yohimbine hydrochloride in the treatment of erection inadequacy. Sexual and Marital Ther 1989; 4(1): 17-26.
  1. Susset JG, Tessier CD, Wincze J, Bansal S, Malhotra C, Schwacha MG. Effect of yohimbine hydrochloride on erectile impotence: A double-blind study. J Urol 1989; 141: 1360-3.
  1. Reid K, Morales A, Harris C, et al. Double-blind trial of yohimbine in treatment of psychogenic impotence. Lancet 1987; Aug 22: 421-3.
  1. Morales A, Condra M, Owen JA, Surridge DH, Fenemore J, Harris C. Is yohimbine effective in the treatment of organic impotence? Results of a controlled trial. J Urol 1987; 137: 1168-72.
  1. Morales A, Surridge DH, Marshall PG, Fenemore J. Nonhormonal pharmacological treatment of organic impotence. J Urol 1982; 128: 45-7.
  1. Charney DS, Heninger GR, Sternberg DE. Assessment of alpha 2 adrenergic autoreceptor function in humans: Effects of oral yohimbine. Life Sci 1982; 30: 2033-41.
  1. Guthrie SK, Hariharan M, Grunhaus LJ. Yohimbine bioavailability in humans. Eur J Clin Pharmacol 1990; 39: 409-11.
  1. Murburg MM, Villacres EC, Ko GN, Veith RC. Effects of yohimbine in human sympathetic nervous system function. J Clin Endocrin Metab 1991; 73(4): 861-5.
  1. Nelson RP. Nonoperative management of impotence. J Urol 1988; 139: 2-5.
  1. Compendium of Pharmaceuticals and Specialties; Canadian Pharmaceutical Association 1992.
  1. Yocon product information, (Glenwood—Canada), Rec 5/92.
  1. Panel consensus, revision 7/92.
  1. Actibine package insert, CMC, Rev 9/85, Rec 8/92.
  1. Panelist comment.
  1. Red book 1993. Montvale, NJ: Medical Economics Data, 1993: 605.
  1. Red book 1993. Montvale, NJ: Medical Economics Data, 1993: 121.
  1. Olin BR, editor. Drug facts and comparisons. St. Louis: Facts and Comparisons Inc, 1992: 850.
  1. Red book 1993. Montvale, NJ: Medical Economics Data, 1993: 606.
  1. PMS-Yohimbine (Pharmascience). In: Krogh CME, editor. CPS Compendium of pharmaceuticals and specialties. 28th ed. Ottawa: Canadian Pharmaceutical Association, 1993: 954.
  1. Yocon (Glenwood), GENERIC (Rougier) (Welcker-Lyster). In: Krogh CME, editor. CPS Compendium of pharmaceuticals and specialties. 28th ed. Ottawa: Canadian Pharmaceutical Association, 1993: 1388-9.
  1. Personal communication, 2/4/94.
  1. Personal communication, 2/4/94.
  1. Red book 1993. Montvale, NJ: Medical Economics Data, 1993: 554.
  1. Dayto Himbin (Dayton). In: PDR Physicians' desk reference. 48th ed. 1994. Montvale, NJ: Medical Economics Data Production Company, 1994: 862.
  1. Prohim (Baker Norton). In: PDR Physicians' desk reference. 48th ed. 1994. Montvale, NJ: Medical Economics Data Production Company, 1994: 577.
  1. Aphrodyne (Star). In: PDR Physicians' desk reference. 48th ed. 1994. Montvale, NJ: Medical Economics Data Production Company, 1994: 2323.
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