Gabapentin Does Not Contain Hydrochloride (HCl)
Gabapentin is formulated and marketed as the free base form, not as a hydrochloride salt. This is distinct from some other medications that may be formulated as HCl salts.
Chemical Formulation
Gabapentin is a structural analogue of the neurotransmitter gamma-aminobutyric acid (GABA) and exists as a water-soluble amino acid compound in its base form 1, 2.
The drug is not protein-bound and is not metabolized, being excreted unchanged in urine 1, 2, 3.
Commercially available gabapentin capsules contain the active ingredient as gabapentin base, not as a salt form 4.
Clinical Context Where HCl Confusion May Arise
In the medical literature discussing combination topical formulations for neuropathic pain, amitriptyline HCl (not gabapentin HCl) is mentioned as a component alongside baclofen and ketamine 5.
This topical gel contains baclofen (10 mg), amitriptyline HCL (40 mg), and ketamine (20 mg) - note that it is the amitriptyline that is in HCl form, not gabapentin 5.
Gabapentin itself, when used for conditions like chemotherapy-induced peripheral neuropathy (CIPN), is administered as the base form orally, typically at doses of 600-1800 mg/day 5.
Pharmaceutical Properties
Gabapentin's water-soluble nature as a free base allows for its unique pharmacokinetic profile, including absorption via a saturable transport mechanism 2, 3.
The drug exhibits dose-dependent bioavailability with plasma concentrations proportional to dosages up to 1,800 mg daily 3.
Its formulation as a free base contributes to its lack of protein binding and absence of hepatic metabolism 1, 2.