Pyridostigmine Bromide Tablets, USP Rx only

Pyridostigmine Bromide Tablets, USP is an orally active cholinesterase inhibitor. Chemically, pyridostigmine bromide is 3-hydroxy-1-methylpyridinium bromide dimethylcarbamate. Its structural formula is:

Pyridostigmine bromide is available as tablets containing 60 mg pyridostigmine bromide; each tablet also contains lactose, silicon dioxide and stearic acid.

Pyridostigmine bromide inhibits the destruction of acetylcholine by cholinesterase and thereby permits freer transmission of nerve impulses across the neuromuscular junction. Pyridostigmine is an analog of neostigmine (Prostigmin), but differs from it in certain clinically significant respects; for example, pyridostigmine is characterized by a longer duration of action and fewer gastrointestinal side effects.

Pyridostigmine Bromide Tablets are useful in the treatment of myasthenia gravis.

Pyridostigmine Bromide Tablets are contraindicated in mechanical intestinal or urinary obstruction, and particular caution should be used in its administration to patients with bronchial asthma. Care should be observed in the use of atropine for counteracting side effects, as discussed below.

Although failure of patients to show clinical improvement may reflect underdosage, it can also be indicative of overdosage. As is true of all cholinergic drugs, overdosage of Pyridostigmine Bromide Tablets may result in cholinergic crisis, a state characterized by increasing muscle weakness which, through involvement of the muscles of respiration, may lead to death. Myasthenic crisis due to an increase in the severity of the disease is also accompanied by extreme muscle weakness, and thus may be difficult to distinguish from cholinergic crisis on a symptomatic basis. Such differentiation is extremely important, since increases in doses of Pyridostigmine Bromide Tablets or other drugs of this class in the presence of cholinergic crisis or of a refractory or "insensitive" state could have grave consequences. Osserman and Genkins ¹ indicate that the differential diagnosis of the two types of crisis may require the use of Tensilon (edrophonium chloride) as well as clinical judgment. The treatment of the two conditions obviously differs radically. Whereas the presence of myasthenic crisis suggests the need for more intensive anticholinesterase therapy, the diagnosis of cholinergic crisis, according to Osserman and Genkins, ¹ calls for the prompt withdrawal of all drugs of this type. The immediate use of atropine in cholinergic crisis is also recommended.

Atropine may also be used to abolish or obtund gastrointestinal side effects or other muscarinic reactions; but such use, by masking signs of overdosage, can lead to inadvertent induction of cholinergic crisis.

For detailed information on the management of patients with myasthenia gravis, the physician is referred to one of the excellent reviews such as those by Osserman and Genkins, ² Grob ³ or Schwab. ^4,5

Pyridostigmine is mainly excreted unchanged by the kidney. ^6,7,8 Therefore, lower doses may be required in patients with renal disease, and treatment should be based on titration of drug dosage to effect. ^6,7

The side effects of Pyridostigmine Bromide Tablets are most commonly related to overdosage and generally are of two varieties, muscarinic and nicotinic. Among those in the former group are nausea, vomiting, diarrhea, abdominal cramps, increased peristalsis, increased salivation, increased bronchial secretions, miosis and diaphoresis. Nicotinic side effects are comprised chiefly of muscle cramps, fasciculation and weakness. Muscarinic side effects can usually be counteracted by atropine, but for reasons shown in the preceding section the expedient is not without danger. As with any compound containing the bromide radical, a skin rash may be seen in an occasional patient. Such reactions usually subside promptly upon discontinuance of the medication.

To report SUSPECTED ADVERSE REACTIONS, contact AvKARE, Inc. at 1-855-361-3993 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Pyridostigmine Bromide Tablets contain 60 mg pyridostigmine bromide each.

Pyridostigmine Bromide Tablets, USP are available containing 60 mg of pyridostigmine bromide supplied in unit dose packaging. NDC 50268-638-15 (10 tablets per card, 5 cards per carton). Each tablet is cross-scored on one side and engraved "OCEANSIDE 302" on the other side.

Store Pyridostigmine Bromide Tablets at 25°C (77°F); excursions permitted to 15° - 30°C (59°-86°F). Keep Pyridostigmine Bromide Tablets in a dry place.

Dispensed in Unit Dose Package. For Institutional Use Only.

1. Osserman KE, Genkins G. Studies in myasthenia gravis: Reduction in mortality rate after crisis. JAMA. Jan 1963; 183:97-101.
2. Osserman KE, Genkins G. Studies in myasthenia gravis. NY State J Med. June 1961; 61:2076-2085.
3. Grob D. Myasthenia gravis. A review of pathogenesis and treatment. Arch Intern Med. Oct 1961; 108:615-638.
4. Schwab RS. Management of myasthenia gravis. New Eng J Med. Mar 1963; 268:596-597.
5. Schwab RS. Management of myasthenia gravis. New Eng J Med. Mar 1963; 268:717-719.
6. Cronnelly R, Stanski DR, Miller RD, Sheiner LB. Pyridostigmine kinetics with and without renal function. Clin Pharmacol Ther. 1980; 28: No. 1, 78-81.
7. Miller RD. Pharmacodynamics and pharmacokinetics of anticholinesterase. In: Rueg-heimer E, Zindler M, ed. Anaesthesiology. (Hamburg, Germany: Congress; Sep 14-21,1980; 222-223.) (Int Congr. No. 538), Amsterdam, Netherlands: Excerpta Medica; 1981.
8. Breyer-Pfaff U, Maier U, Brinkmann AM, Schumm F. Pyridostigmine kinetics in healthy subjects and patients with myasthenia gravis. Clin Pharmacol Ther. 1985; 5:495-501.

Manufactured for:

AvKARE, Inc.

Pulaski, TN 38478

Mfg. Rev. 08/16

AV 08/19 (P)

AvPAK

60mg