Miscellaneous immune disorders:

Indications for FIRDAPSE:

Lambert-Eaton myasthenic syndrome (LEMS).


Initially 15–30mg daily in 3–4 divided doses. May increase by 5mg every 3 or 4 days. Max 80mg/day. Max single dose: 20mg. Hepatic or renal impairment (CrCl 15–90mL/min), NAT2 poor metabolizers: 15mg daily in 3 divided doses.


Not established.


History of seizures.


Consider dose reduction or discontinuation if seizure occurs. Discontinue and treat if anaphylaxis occurs. Hepatic or renal impairment: monitor; adjust dose or discontinue as needed. N-acetyltransferase 2 (NAT2) poor metabolizers. Elderly. Pregnancy. Nursing mothers.

Pharmacologic Class:

Potassium channel blocker.


Concomitant drugs that lower seizure threshold may increase seizure risk. Additive effects when concomitant drugs with cholinergic effects (eg, direct or indirect cholinesterase inhibitors).

Adverse Reactions:

Paresthesia, upper RTI, abdominal pain, nausea, diarrhea, headache, elevated liver enzymes, back pain, hypertension, muscle spasms; seizures, hypersensitivity.

Generic Availability:


How Supplied:

Tabs—60, 240; Blister packs—10, 120