Comparative Pharmacology
Head-to-head clinical analysis: LYRICA versus PRIMIDONE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LYRICA versus PRIMIDONE.
LYRICA vs PRIMIDONE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Binds to the α2-δ subunit of voltage-gated calcium channels, reducing calcium influx and inhibiting release of excitatory neurotransmitters including glutamate, norepinephrine, and substance P.
Primidone is a barbiturate that enhances GABA-A receptor activity, increasing chloride ion conductance and neuronal inhibition. It also has active metabolites, phenobarbital and phenylethylmalonamide, which contribute to anticonvulsant effects.
Oral: 75-150 mg twice daily or 50-100 mg three times daily; maximum 600 mg/day. Start at 75 mg twice daily.
Initial: 100-125 mg orally at bedtime for 3 days; increase to 100-125 mg twice daily for 3 days, then 100-125 mg three times daily for 3 days; maintenance: 250 mg three times daily. Maximum: 500 mg four times daily.
None Documented
None Documented
Clinical Note
moderatePrimidone + Digoxin
"The metabolism of Digoxin can be increased when combined with Primidone."
Clinical Note
moderatePrimidone + Digitoxin
"The metabolism of Digitoxin can be increased when combined with Primidone."
Clinical Note
moderatePrimidone + Torasemide
"The metabolism of Torasemide can be increased when combined with Primidone."
Clinical Note
moderatePrimidone + Etacrynic acid
"Primidone may increase the hypotensive activities of Etacrynic acid."
Terminal elimination half-life is 6.3 hours (range 5.5–6.7 hours) in patients with normal renal function. Half-life increases in renal impairment (up to 48 hours in anuria).
Primidone: 10-12 hours; phenobarbital metabolite: 48-120 hours; PEMA: 16-18 hours. Steady-state requires 4-7 days for primidone but up to 2-3 weeks for phenobarbital accumulation.
Renal excretion of unchanged drug accounts for approximately 90% of elimination; less than 1% is secreted in feces or bile. Dose adjustment required in renal impairment (CrCl <60 mL/min).
Renal: approximately 40% unchanged, 30% as phenobarbital, 20% as phenylethylmalonamide (PEMA); fecal: <5%
Category C
Category D/X
Anticonvulsant
Anticonvulsant