Yohimbine

Used to increase Athletic performance ; Autonomic failure ; Platelet aggregation inhibition ; Sexual side effects of SSRIs;Sexual vitality (men and women); male erectile dysfunction ;Xerostomia (psychotropic drug-induced).

Contraindicated in pregnancy, hypertensive individuals , cardiovascular disease.
Do not use in individuals taking MAO inhibitors or antihypertensives.
Avoid using in individuals with benign prostatic hypertrophy (BPH) because yohimbine, the active constituent of yohimbe, may exacerbate symptoms of BPH due to its presynaptic alpha2 blocking ability.

Use with caution in individuals receiving alpha2 blockers;
Use all herbal supplements with extreme caution in children <2 years of age and in pregnancy or lactation. Some herbs are contraindicated in pregnancy or lactation.Use caution in individuals having known allergies to plants.

Toxic doses may trigger psychosis, hypotension, and cardiac failure. may cause CNS stimulation (anxiety, insomnia), hypertension, and tachycardia.
Refractory priapism was reported and associated with yohimbe extract ingestion.
Acute nephrotoxicity has also been reported after yohimbine use.

Yohimbine in combination with drugs that inhibit the reuptake of norepinephrine, such as dextromethorphan, tramadol, some antidepressants and central nervous system stimulants used to treat ADHD, can cause a hypertensive crises. This is due to those drugs in combination with an a2 receptor antagonist leads to too much norepinephrine in the brain, which causes blood pressure to spike to dangerous levels.
More serious adverse effects may include seizures and renal failure. Yohimbine should not be consumed by anyone with liver, kidney, heart disease, or a psychological disorder.
The therapeutic index of yohimbine is quite low; the range between an effective dose and a dangerous dose is very narrow.A typical dose for sexual dysfunction would be 15-30mg, whereas 100mg would be considered dangerous. This may also lead to the precipitation of panic disorder type reactions, heart attack and possibly death.
Yohimbine in combination with modafinil is frequently associated with nausea, dangerous acute rapid heart beat, and acute increased blood pressure. Yohimbine exhibits some degree of MAOI activity while modafinil has been shown to increase levels of various monamines and therefore could result in severe risk of dangerous side effects.

Adrenergic/antiadrenergic agents, alpha2-blockers, amphetamines, antidiabetic medications, antihistamines, antihypertensives, antimuscarinic agents, benzodiazepines, clonidine, cytochrome P450 metabolized agents, ethanol, linezolid, MAO inhibitors, morphine, naloxone, phenothiazines, physostigmine, sildenafil, stimulants, sympathomimetics, tricyclic antidepressants.

The alkaloid yohimbine has central nervous system stimulatory activity. Also, yohimbine has selective alpha2 adrenergic blocking properties, which is the basis for its use in erectile dysfunction. Yohimbine also blocks peripheral 5-HT receptors. Aphrodisiac activity may be due to enlargement of the vasculature in the genitals, increase of nerve impulses to genital tissue, and an increased transmission of reflex excitability in the sacral region of the spinal cord.