pyridostigmine bromide


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pyridostigmine bromide

Mestinon, Mestinon-SR (CA), Mestinon Timespan, Regonol

Pharmacologic class: Anticholinesterase

Therapeutic class: Muscle stimulant, antimyasthenic

Pregnancy risk category C

Action

Prevents acetylcholine destruction, resulting in stronger contractions of muscles weakened by myasthenia gravis or curare-like neuromuscular blockers

Availability

Injection: 5 mg/ml

Syrup: 60 mg/5 ml

Tablets: 60 mg

Tablets (extended-release): 180 mg

Indications and dosages

Myasthenia gravis

Adults: 600 mg P.O. given over 24 hours, with doses spaced for maximum symptom relief. For myasthenic crisis, 2 mg or 1/30 of oral dose I.M. or very slow I.V. q 2 to 3 hours.

Postoperative reversal of nondepolarizing neuromuscular blockers

Adults: 10 to 20 mg slow I.V. injection (range is 0.1 to 0.25 mg/kg) with or immediately after 0.6 to 1.2 mg atropine sulfate I.V.

Dosage adjustment

• Renal impairment

• Seizure disorders

Off-label uses

• Myasthenia gravis in children

• Constipation in patients with Parkinson's disease

• Nerve agent prophylaxis

Contraindications

• Hypersensitivity to drug or bromides

• Mechanical intestinal or urinary tract obstruction

Precautions

Use cautiously in:

• seizure disorders, bronchial asthma, coronary occlusion, arrhythmias, bradycardia, hyperthyroidism, peptic ulcer, vagotonia, cholinergic crisis

• pregnant or breastfeeding patients

• children (safety and efficacy not established).

Administration

Don't exceed I.V. injection rate of 1 mg/minute.

Don't give concurrently with other anticholinesterase drugs.

• Have atropine available for use in emergencies.

Adverse reactions

CNS: headache, dysarthria, dysphoria, drowsiness, dizziness, headache, syncope, loss of consciousness, seizures

CV: decreased cardiac output leading to hypotension, bradycardia, nodal rhythm, atrioventricular block, cardiac arrest, arrhythmias

EENT: diplopia, lacrimation, miosis, spasm of accommodation, conjunctival hyperemia

GI: nausea, vomiting, diarrhea, abdominal cramps, increased peristalsis, flatulence dysphagia, increased salivation

GU: urinary frequency, urgency, or incontinence

Musculoskeletal: muscle weakness, fasciculations, and cramps; joint pain

Respiratory: increased pharyngeal and tracheobronchial secretions, dyspnea, central respiratory paralysis, respiratory muscle paralysis, laryngospasm, bronchospasm, bronchiolar constriction

Skin: diaphoresis, flushing, rash, urticaria

Other: thrombophlebitis at I.V. site, cholinergic crisis, anaphylaxis

Interactions

Drug-drug. Aminoglycosides: potentiation of neuromuscular blockade

Anesthetics (general and local), antiarrhythmics: decreased anticholinesterase effects

Atropine, belladonna derivatives: suppression of parasympathomimetic GI symptoms (leaving only fasciculations and voluntary muscle paralysis as signs of anticholinesterase overdose)

Corticosteroids: decreased anticholinesterase effects; after corticosteroid withdrawal, increased anticholinesterase effects

Ganglionic blockers (such as mecamy-lamine): increased anticholinesterase effects

Magnesium: antagonism of beneficial anticholinesterase effects

Nondepolarizing neuromuscular blockers (atropine, pancuronium, tubocurarine): antagonism of neuromuscular blockade and reversal of muscle relaxation after surgery (with parenteral pyridostigmine)

Other anticholinesterase drugs: in patients with myasthenia gravis, symptoms of anticholinesterase overdose that mimic underdose, causing patient's condition to worsen

Succinylcholine: increased and prolonged neuromuscular blockade (including respiratory depression)

Patient monitoring

• Assess patient's response to each dose.

• Monitor vital signs, ECG, and cardiovascular and respiratory status.

Assess for signs and symptoms of overdose, which indicate cholinergic crisis.

Patient teaching

• If patient is using syrup, advise him to pour it over ice.

• Instruct patient using extended-release tablets not to crush them.

Teach patient to recognize and promptly report signs and symptoms of overdose, including muscle fasciculations, sweating, excessive salivation, and constricted pupils.

• Tell patient drug may cause headache and muscle cramps. Encourage him to discuss activity recommendations and pain management with prescriber.

• Advise patient to monitor and report his response to ongoing therapy so that optimal dosage can be determined.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs mentioned above.

py·ri·do·stig·mine bro·mide

(PB) (pir'i-dō-stig'mēn brō'mīd)
The bromide salt of a carbamate compound; the salt used as a preexposure antidotal enhancer (often incorrectly termed "pretreatment") against the nerve agent soman.
Synonym(s): 2-PAM chloride.

Pyridostigmine bromide (Mestinon)

An anticholinesterase drug used in treating myasthenia gravis.
Mentioned in: Myasthenia Gravis
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Group I--Con-NT: wild-type C57BL/6j mice were injected with vehicle as a control (Con), not treated (NT) with pyridostigmine bromide and evaluated after six months at the end of the observation period;
Use of pyridostigmine bromide prevents permanent binding of
Locomotor and sensorimotor performance deficit in rats following exposure to pyridostigmine bromide, DEET, and permethrin, alone and in combination.
2, 1990-July 31, 1991) 696,628 Troops believed to have been exposed to chemical warfare agents 100,000 Troops who received pyridostigmine bromide 250,000 Troops who received botulism vaccine 8,000 Troops who received anthrax vaccine 150,000 Troops believed to have been exposed to depleted uranium 436,000 Source: National Gulf War Resource Center Gulf theater troops filing disability claims with the VA 249,810 VA claims granted 192,024 VA claims denied 26,410 VA claims pending 31,376 Source: VA Office of Public Affairs, July 15, 2000 SOURCES FOR HELP
He had followed the mystery surrounding Gulf War illnesses and knew the troops had doused themselves, their clothing, and their tents with insecticides, including permethrin and Deet; he learned that some had also taken pyridostigmine bromide (PB), a prophylactic antidote to nerve gas.
Some of Zydus' recent launches include potassium chloride extended-release tablets 8mEq, etomidate injection, morphine sulfate extended-release tablets, isosorbide mononitrate extended-release tablets, and pyridostigmine bromide tablets.
Now, 17 years after the Gulf War, the congressionally mandated Research Advisory Committee on Gulf War Veterans' Illnesses has officially released a 450-page report which confirms that Gulf War Illness is a result of soldiers' exposure to neurotoxic chemicals, including pyridostigmine bromide and pesticides.
Oncreased neurotoxicity following concurrent exposure to pyridostigmine bromide, DEET, and chlorpyrifos.
In that study, Mark Kupersmith, M.D., of Beth Israel Medical Center, New York, reviewed 147 patients with ocular myasthenia who received either prednisone, pyridostigmine bromide, or no pharmacotherapy.
Depleted Uranium, Pyridostigmine Bromide, Sarin, and Vaccines, analyzed 16 peer-reviewed studies of both chronic and acute pesticide exposures.
If dry mouth or constipation does develop, try adding the cholinesterase inhibitor Mestinon (pyridostigmine bromide), which does not interfere with amitriptyline's action, he added.
Researchers think the ill vets had a genetic vulnerability to certain chemicals used in the war, such as nerve gas, the insecticide DEET, pet flea collars used to repel pests and the anti-nerve-gas drug pyridostigmine bromide, also known as PB.