
Gastrointestinal: difficulty swallowing, heartburn, flatulence, constipation. Mental confusion, excitement, or depression can also occur due to intolerance, particularly in elderly or debilitated patients, or due to overdosage of butalbital.Īutonomic Nervous System: dry mouth, hyperhidrosis. Call your doctor if you took more than the recommended dose.Īll adverse events tabulated below are classified as infrequent.Ĭentral Nervous System: headache, shaky feeling, tingling, agitation, fainting, fatigue, heavy eyelids, high energy, hot spells, numbness, sluggishness, seizure.

The in vitro plasma protein binding of butalbital is 45% over the concentration range of 0.5-20 mcg/mL. Of the material excreted in the urine, 32% is conjugated.

Urinary excretion products include parent drug (about 3.6% of the dose), 5-isobutyl-5-(2, 3-dihydroxypropyl) barbituric acid (about 24% of the dose), 5-allyl-5(3-hydroxy-2-methyl-1-propyl) barbituric acid (about 4.8% of the dose), products with the barbituric acid ring hydrolyzed with excretion of urea (about 14% of the dose), as well as unidentified materials. They are bound to plasma and tissue proteins to a varying degree and binding increases directly as a function of lipid solubility.Įlimination of butalbital is primarily via the kidney (59% to 88% of the dose) as unchanged drug or metabolites. Barbiturates in general may appear in breast milk and readily cross the placental barrier. Butalbital is well absorbed from the gastrointestinal tract and is expected to distribute to most tissues in the body.
