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Pronunciation: GWAHN-ih-deen
Class: Cholinergic muscle stimulant

Trade Names

Guanidine Hydrochloride
- Tablets 125 mg


Enhances release of acetylcholine following a nerve impulse and appears to slow rates of depolarization and repolarization of muscle cell membranes.

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Indications and Usage

Reduce symptoms of muscle weakness and easy fatigability associated with Lambert-Eaton syndrome.

Unlabeled Uses

Treatment of botulism.


Standard considerations.

Dosage and Administration


PO Start with 10 to 15 mg/kg/day in 3 or 4 divided doses, gradually increasing the dose to 35 mg/kg/day or up to the development of adverse reactions.

General Advice

Administer without regard to meals. Administer with food if GI upset occurs.


Store tablets at controlled room temperature (59° to 86°F).

Drug Interactions

None well documented.

Laboratory Test Interactions

None well documented.

Adverse Reactions


Palpitation; tachycardia; atrial fibrillation; hypotension.


Paresthesia of lips, face, hands, and feet; cold sensations in hands and feet; nervousness; lightheadedness; increased irritability; jitteriness; tremor; trembling sensations; ataxia; emotional lability; psychotic state; confusion; mood changes; hallucination.


Rash; flushing or pink complexion; folliculitis; petechiae; purpura; ecchymosis; sweating; skin eruptions; dryness and scaling of the skin.


Sore throat.


Dry mouth; anorexia; gastric irritation; nausea; diarrhea; abdominal cramping.


Uremia; chronic interstitial nephritis; renal tubular necrosis; acute interstitial nephritis.


Serum creatinine elevation; bone marrow suppression with anemia, leukopenia, and thrombocytopenia.

Lab Tests

Abnormal LFTs.





Muscle strength and function

Frequently assess muscle strength and function. Notify health care provider immediately of increasing muscle weakness and/or respiratory distress. Ensure that parenteral atropine is available for emergency treatment of cholinergic crisis.


Safety for use in pregnancy not established.


Excreted in breast milk.


Safety and efficacy not established.

Renal Function

Renal function may be affected in some patients.

Bone marrow suppression

Dose-related fatal bone marrow suppression can occur. Avoid coadministration of other drugs that may cause bone marrow suppression. Ensure that CBC with differential is obtained before starting therapy and repeated frequently during treatment.



Mild GI symptoms (eg, increased peristalsis, anorexia, diarrhea), slight numbness and tingling on the lips and fingertips, nervous hyperirritability, fibrillary tremors, convulsive muscle contractions, salivation, vomiting, hypoglycemia, circulatory disturbances.

Patient Information

  • Advise patient that dose and frequency of administration may be adjusted to achieve maximum benefit.
  • Advise patient to take exactly as prescribed and not to change the dose or stop taking unless advised by health care provider.
  • Advise patient to take prescribed dose without regard to meals but to take with food if stomach upset occurs.
  • Instruct patient to contact health care provider immediately if any of the following occur: worsening muscle weakness, difficulty breathing, rash or sore throat, fever, other signs of infection.
  • Advise patient to inform health care provider if nervousness, tremor, or persistent nausea or diarrhea occur.

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