PROCOMIL TABLETS

Indications

• Erectile dysfunction
• Impotence
• Sexual dysfunction

Dosage

Children: Yohimbine is not typically indicated for pediatric use; refer to the BNF for Children for specific guidance.

Adults: The usual dose for adults is 5.4 mg three times a day, taken before meals. Doses may be adjusted based on individual response and tolerance.

Mechanism of action

Yohimbine acts as a pre-synaptic alpha 2-adrenergic blocker. This blockade increases sympathetic drive, leading to enhanced norepinephrine release and increased firing rates of noradrenergic neurons in the brain. Additionally, it may influence other neurotransmitters such as dopamine and serotonin, playing a role in its effects on erectile function and mood.

Pharmacodynamics

Yohimbine is characterized as an indolalkylamine alkaloid with structural similarities to reserpine. Its pharmacological action includes the blockade of presynaptic alpha-2 adrenergic receptors, which modifies peripheral autonomic nervous system activity by stimulating parasympathetic (cholinergic) actions and inhibiting sympathetic (adrenergic) responses. Its effects on male sexual function are linked to increased cholinergic activity and alpha-2 blockade, potentially enhancing penile blood flow.

Pharmacokinetics

Yohimbine is absorbed following oral administration and exhibits a moderate half-life. It has a distribution pattern that allows it to cross the blood-brain barrier, contributing to its central nervous system effects. Metabolism primarily occurs in the liver, with excretion mainly through the kidneys. Its pharmacokinetic profile indicates variability based on individual factors such as age, health status, and concomitant medications.

Contra-indications

• Hypersensitivity to yohimbine or any of its components
• Severe renal impairment
• Severe cardiovascular disorders
• History of anxiety or panic disorders

Adverse effects

• Increased heart rate
• Hypertension
• Anxiety
• Nausea
• Dizziness
• Insomnia
• Headache
• Gastrointestinal disturbances

Interactions

• Monoamine oxidase inhibitors (MAOIs) may enhance the effects of yohimbine
• Other sympathomimetics may have additive effects
• Antihypertensives may have reduced effectiveness

Precautions

• Use with caution in patients with a history of cardiovascular disease
• Monitor blood pressure regularly during treatment
• Caution advised in patients with psychiatric disorders

Pregnancy

Yohimbine is not recommended during pregnancy due to lack of safety data.

Breast-feeding

Caution is advised as it is unknown if yohimbine is excreted in human milk.

Storage

Store at room temperature, in a dry place away from light.

Formulations

• Tablets
• Capsules
• Oral solutions

Indications

• Erectile dysfunction
• Aphrodisiac
• Orthostatic hypotension
• Veterinary medicine as a reversal agent for certain anesthetics

Dosage

Adults: The usual oral dose for erectile dysfunction is 5.4 to 6 mg three times daily, with a

Mechanism of action

Yohimbine hydrochloride exerts its pharmacological effects mainly through the selective blockade of alpha-2 adrenergic receptors, leading to increased release of norepinephrine. This results in enhanced sympathetic outflow, which may improve erectile function and libido. The increased norepinephrine also promotes vasodilation and increased blood flow to the genital area, contributing to its aphrodisiac effects.

Pharmacodynamics

The pharmacodynamic profile of yohimbine includes its ability to antagonize alpha-2 adrenergic receptors, leading to an increase in norepinephrine release. This results in a range of effects including increased heart rate, blood pressure, and improved blood flow. The anxiogenic and stimulant effects of yohimbine can also be attributed to its action on central nervous system receptors. The onset of action may vary, and the duration of effects can last several hours depending on the individual response.

Pharmacokinetics

Yohimbine hydrochloride is well-absorbed after oral administration, with peak plasma concentrations typically occurring within 1 to 2 hours. The bioavailability can be affected by food intake. It is extensively metabolized in the liver, and its metabolites are primarily excreted via the kidneys. The elimination half-life of yohimbine is approximately 5 hours, but this may vary among individuals due to differences in metabolism. Factors such as age, liver function, and concurrent medications can influence its pharmacokinetic profile.

Contra-indications

• Hypersensitivity to yohimbine or any component of the formulation
• Patients with a history of cardiovascular disease
• Patients with renal impairment
• Patients taking monoamine oxidase inhibitors (MAOIs)

Adverse effects

• Hypertension
• Tachycardia
• Anxiety
• Dizziness
• Nausea
• Headache

Interactions

• Caution when used with other antihypertensive medications
• May interact with antidepressants, particularly MAOIs
• Caution with sympathomimetic agents

Precautions

• Use with caution in patients with psychiatric disorders
• Monitor blood pressure regularly during treatment
• Consider potential for drug interactions
• Assess renal function before prescribing

Pregnancy

There is insufficient evidence regarding the safety of yohimbine in pregnancy, use only if potential benefit justifies the risk.

Breast-feeding

The excretion of yohimbine in human milk is not well studied, caution is advised.

Storage

Store in a cool, dry place away from light. Keep out of reach of children.

Formulations

• Yohimbine hydrochloride tablets
• Yohimbine hydrochloride injectable solution

Mechanism of action

Yohimbine is a pre-synaptic alpha 2-adrenergic blocking agent. The exact mechanism for its use in impotence has not been fully elucidated. 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. 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.

Pharmacodynamics

Yohimbine is an indolalkylamine alkaloid with chemical similarity to reserpine. Yohimbine blocks presynaptic alpha-2 adrenergic receptors. Its action on peripheral blood vessels resembles that of reserpine, though it is weaker and of short duration. Yohimbine's peripheral autonomic nervous system effect is to increase parasympathetic (cholinergic) and decrease sympathetic (adrenergic) activity. It is to be noted that in male sexual performance, erection is linked to cholinergic activity and to alpha-2 adrenergic blockade which may theoretically result in increased penile inflow, decreased penile outflow or both. Yohimbine exerts a stimulating action on the mood and may increase anxiety. Such actions have not been adequately studied or related to dosage although they appear to require high doses of the drug. Yohimbine has a mild anti-diuretic action, probably via stimulation of hypothalmic center and release of posterior pituitary hormone. Reportedly Yohimbine exerts no significant influence on cardiac stimulation and other effects mediated by (beta)-adrenergic receptors. Its effect on blood pressure, if any, would be to lower it; however, no adequate studies are at hand to quantitate this effect in terms of Yohimbine dosage.