Bethanechol Chloride

Bethanechol chloride (bethanechol) , a cholinergic agent, is a synthetic esler which is structurally and pharmacologically related to acetylcholine.

It is designated chemically as Z-[(aminocarbony) oxy]-N, N, (V-trimethyl-1-propanaminium chloride. Its molecular formula is C7H17CIN202 and its structural formula is:

It is a white, hygroscopic crystalline powder having a slight amine-like odor, freely soluble in water, and has a molecular weight of 196.68.

Each tablet for oral administration contains 5 mg, 10 mg, 25 mg or 50 mg bethanechol chloride, USP Tablets also contain the following inactive ingredients: colloidal silicon dioxide, lactose monohydrate, magnesium stearate, microcrystalline cellulose, sodium starch glycolate, (25 mg and 50 mg) D&C~ Yellow # 10 Lake and FD&C Yellow # 6 Lake.

Bethanechol Chloride Tablets USP

Dispense in a tight container as defined in the USP.

Store at 20°-25°C (68°-77°F).

Bottle contains desiccant.

Manufactured by: Wockhardt Limited, Mumbai, India. Distributed by: Wockhardt USA LLC., 20 Waterview Blvd. Parsippany, NJ 07054, USA. Revised: Aug 2010

Bethanechol chloride acts principally by producing the effects of stimulation of the parasympathetic nervous system. It increases the tone of the detrusor urinae muscle, usually producing a contraction sufficiently strong to initiate micturition and empty the bladder. It stimulates gastric motility, increases gastric tone and often restores impaired rhythmic peristalsis.

Stimulation of the parasympathetic nervous system releases acetylcholine at the nerve endings. When spontaneous stimulation is reduced and therapeutic intervention is required, acetylcholine can be given, but it is rapidly hydrolyzed by cholinesterase and its effects are transient. Bethanechol chloride is not destroyed by cholinesterase and its effects are more prolonged than those of acetylcholine.

Effects on the GI and urinary tracts sometimes appear within 30 minutes after oral administration of bethanechol chloride, but more often 60 to 90 minutes are required to reach maximum effectiveness. Following oral administration, the usual duration of action of bethanechol is one hour, although large doses (300 to 400 mg) have been reported to produce effects for up to six hours. Subcutaneous injection produces a more intense action on bladder muscle than does oral administration of the drug.

Because of the selective action of bethanechol, nicotinic symptoms of cholinergic stimulation are usually absent or minimal when orally or subcutaneously administered in therapeutic doses, while muscarinic effects are prominent. Muscarinic effects usually occur within 5 to 15 minutes after subcutaneous injection, reach a maximum in 15 to 30 minutes, and disappear within two hours. Doses that stimulate micturition and defecation and increase peristalsis do not ordinarily stimulate ganglia or voluntary muscles. Therapeutic test doses in normal human subjects have little effect on heart rate, blood pressure or peripheral circulation.

Bethanechol chloride does not cross the blood-brain barrier because of its charged quaternary amine moiety. The metabolic rate and mode of excretion of the drug have not been elucidated.

A clinical study (Diokno, AC.; Lapides, J.; Urol 10 : 23-24, July 1977) was conducted on the relative effectiveness of oral and subcutaneous doses of bethanechol chloride on the stretch response of bladder muscle in patients with urinary retention. Results showed that 5 mg of the drug given subcutaneously stimulated a response that was more rapid in onset and of larger magnitude than an oral dose of 50 mg, 100 mg, or 200 mg. All the oral doses, however, had a longer duration of effect than the subcutaneous dose. Although the 50 mg oral dose caused little change in intravesical pressure in this study, this dose has been found in other studies to be clinically effective in the rehabilitation of patients with decompensated bladders.

Cholinergic agonist.a

Storage

Oral

Tight containers at 20–25°C.104 a

• Inform patient to take 1 hour before or 2 hours after meals to avoid nausea or vomiting.104

• Risk of dizziness, lightheadedness, or fainting.104 Use caution when rising from a lying or sitting position.104

• Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs.104 a

• Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.104 a

• Importance of informing patients of other important precautionary information.104 a (See Cautions.)

Before taking this medication, tell your doctor if you

• have uncontrolled hyperthyroidism (an overactive thyroid);
• have stomach ulcers;
• have asthma;
• have recently had bladder or intestinal surgery;
• have a blockage in your intestinal tract;
• have a slow heart rate or low blood pressure;
• have a disease or blockage of the arteries in your heart (coronary artery disease);
• have epilepsy or any other seizure disorder; or
• have Parkinson's disease.

You may not be able to take bethanechol, or you may require a lower dose or special monitoring during treatment if you have any of the conditions listed above.

Bethanechol is in the FDA pregnancy category C. This means that it is not known whether bethanechol will harm an unborn baby. Do not take this medication without first talking to your doctor if you are pregnant.

It is not known whether bethanechol passes into breast milk. Do not take this medication without first talking to your doctor if you are breast-feeding a baby.

Take the missed dose as soon as you remember. However, if it is almost time for your next dose, skip the missed dose and take only your next regularly scheduled dose. Do not take a double dose of this medication.