PDR for Herbal Medicines

844/YOHIMBE BARK PDR FOR HERBAL MEDICINES

frequency of sexual contacts, and quality of erection (penile

rigidity) during sexual contact or intercourse. Objective

criteria were based on improvement in penile rigidity

determined by use of polysomnography in the sleep laborato-

ry. Yohimbine was overall significantly more effective than

placebo for response rate and was well tolerated (Vogt, 1970.

Mixed-type ErecTile Dysfunction

The effect of yohimbine hydrochloride was evaluated in the

treatment of mixed-type impotence. A randomized, double-

blind, placebo-controlled, crossover trial included 29 patients

administered either yohimbine hydrochloride 36 mg daily or

placebo. The two groups received therapy for 25 days, then a

washout period of 14 days, and finally, a switch of treatment

groups for an additional 25 days. Positive clinical results

were seen in 44% and 48% of patients in the yohimbine and

placebo groups, respectively, with no significant difference

between the groups (Kunelius, 1997).

Pressor Effects with Autonomic Failure

In 35 patients with severe orthostatic hypotension due to

multiple system atrophy or pure autonomic failure, the effect

was determined on seated systolic blood pressure (SBP) of

placebo, phenylpropanolamine (12.5 mg and 25 mg), yohim-

bine (5.4 mg), indomethacin (50 mg), ibuprofen (600 mg),

caffeine (250 mg), and methylphenidate (5 mg). The pressor

response was significant for phenylpropanolamine, yohim-

bine, and indomethacin compared with placebo. In a

subgroup of patients, the pressor effect was confirmed of

phenylpropanolamine, yohimbine, and indomethacin corre-

sponding to a significant increase in standing SBP. The

pressor responses to ibuprofen, caffeine, and methylpheni-

date were not significantly different from placebo, and

phenylpropanolamine and midodrine exerted similar pressor

responses (Jordan, 1998).

INDICATIONS AND USAGE

FDA Approved Indications: Yohimbine Hydrochloride is

indicated as a sympatholytic and mydriatic. Impotence has

been successfully treated with Yohimbine in male patients

with vascular or diabetic origins and psychogenic origins.

Unproven Uses: Yohimbe bark is used as an aphrodisiac,

and for debility and exhaustion.

CONTRAINDICATIONS

Yohimbe bark is contraindicated in liver and kidney

diseases.

PRECAUTIONS AND ADVERSE REACTIONS
General: Side effects that can appear include anxiety states,
elevated blood pressure, exanthema, nausea, insomnia,
tachycardia, tremor, and vomiting.

Posttraumatic Stress Disorder (PTSD): Yohimbine was

reported to exacerbate anxiety/panic and PTSD-specific

symptoms after oral ingestion of the drug (Southwick, 1999).

Patients with PTSD consists of 2 subgroups, one with a

sensitized noradrenergic system, and the other with a A

sensitized serotonergic system, and is why yohimbine-in-

duced panic attacks occur in different patients (Southwick,

1997).

Hypertension: Yohimbine induced a significant increase in

diastolic pressure, but only in hypertensive patients due to an

alpha 2-adrenoreceptor desensitization or an alteration in the

balance of alpha-adrenoreceptors in human hypertension

(Musso, 1995).

Auditory Effects: The drug has been associated with a

transient impairment in auditory sensory gating (Adler,

1994).

'Salivation: Yohimbine significantly increases salivary flow

in patients treated with psychotropic drugs (tricyclic antide-

pressants or neuroleptics) suffering from xerostomia (Bagh-

eri. 1997).

Panic Disorder: Patients with agoraphobia with panic

attacks had greater autonomic anxiety symptoms, increase in

SBP and Cortisol responses to yohimbine than healthy *

patients. Yohimbine also induced panic episodes in these

patients (Gurguis, 1997).

Parkinson's Disease: Patients with Parkinson's Disease have

demonstrated a vulnerability to yohimbine-induced somatic

symptoms such as panic attacks (Richard, 1999).

Drug Interactions:

Naltrexone — Clinically used naltrexone doses alter sensitiv-

ity to yohimbine, and potentiates the drug's side effects, such

as nervousness (Rosen, 1999).

Anti-hypertensive Medications — Because of the increase in

diastolic pressure in hypertensive patients, caution should be

taken with concomitant use of anti-hypertensive medications

(Musso, 1995).

Ethanol — Intoxicating and anxiogenic effects of acute

ethanol administration may be associated with increase

norepinephrine turnover when administered concomitantly

with yohimbine (McDougle, 1995).

OTC stimulants — These may have alpha-1 adrenergic

receptor activity to potentiate hypertension when yohimbine

is given concomitantly.

Morphine — The overall analgesic effect of morphine was

significantly enhanced in the presence of yohimbine in one

study (Gear, 1995).