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Tofranil (Imipramine Hydrochloride) - Description and Clinical Pharmacology


Prescribing Information


Tofranil™ is supplied in tablet form for oral administration.

Tofranil, imipramine hydrochloride USP, the original tricyclic antidepressant, is a member of the dibenzazepine group of compounds. It is designated 5-3-(dimethylamino)propyl-10,11-dihydro-5H-dibenz [b,f]-azepine monohydrochloride. Its structural formula is:

Imipramine hydrochloride USP is a white to off-white, odorless, or practically odorless crystalline powder. It is freely soluble in water and in alcohol, soluble in acetone, and insoluble in ether and in benzene.

Inactive Ingredients: Calcium phosphate, cellulose compounds, docusate sodium, iron oxides, magnesium stearate, polyethylene glycol, povidone, sodium starch glycolate, sucrose, talc, and titanium dioxide.


The mechanism of action of Tofranil is not definitely known. However, it does not act primarily by stimulation of the central nervous system. The clinical effect is hypothesized as being due to potentiation of adrenergic synapses by blocking uptake of norepinephrine at nerve endings. The mode of action of the drug in controlling childhood enuresis is thought to be apart from its antidepressant effect.


A. Acute: Oral LD50 ranges are as follows:

      Rat      355 to 682 mg/kg

      Dog     100 to 215 mg/kg

Depending on the dosage in both species, toxic signs proceeded progressively from depression, irregular respiration and ataxia to convulsions and death.

B. Reproduction/Teratogenic: The overall evaluation may be summed up in the following manner:

Oral: Independent studies in three species (rat, mouse, and rabbit) revealed that when Tofranil is administered orally in doses up to approximately 2-1/2 times the maximum human dose in the first 2 species and up to 25 times the maximum human dose in the third species, the drug is essentially free from teratogenic potential. In the three species studied, only one instance of fetal abnormality occurred (in the rabbit) and in that study there was likewise an abnormality in the control group. However, evidence does exist from the rat studies that some systemic and embryotoxic potential is demonstrable. This is manifested by reduced litter size, a slight increase in the stillborn rate, and a reduction in the mean birth weight.

Tofranil and 

are trademarks of Mallinckrodt Inc.

Manufactured by:
Patheon Inc.
Whitby, Ontario, Canada
L1N 5Z5

Manufactured for:
Mallinckrodt Inc.
Hazelwood, MO 63042 USA

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