JWH-398

JWH-398 is a synthetic cannabinoid in the naphthoylindole family. It is a chlorinated analogue of JWH-018, with a chlorine atom at the 4-position of the naphthalene ring. Laboratory studies report low-nanomolar CB₁ receptor affinity, and forensic databases classify it as a synthetic cannabinoid receptor agonist. Human clinical information specific to JWH-398 remains limited.

Chemistry and identification

JWH-398 is (4-chloronaphthalen-1-yl)(1-pentyl-1H-indol-3-yl)methanone. It retains the N-pentylindole structure of JWH-018, but has a chlorine substituent on the naphthalene ring. It should not be confused with JWH-203, which is a phenylacetylindole with a 2-chlorophenyl group.

UNODC lists JWH-398 as a synthetic cannabinoid receptor agonist and provides its chemical identity, molecular formula and CAS number (UNODC substance record: JWH-398).

Pharmacology

JWH-398 binds to the CB₁ receptor with a reported Ki of approximately 2.3 nM. In the 4-halogenated naphthoylindole series, the 4-chloro substituent generally produces strong CB₁ affinity when combined with an N-pentyl chain. One review reports slight CB₁ selectivity for JWH-398, although the precise balance between CB₁ and CB₂ depends on the assay (The Cannabinoid Receptors, 2009).

These binding results support cannabinoid receptor activity, but do not independently establish functional efficacy or the intensity of human effects.

Reported effects

There is little reliable human information that isolates JWH-398 from other synthetic cannabinoids. Its receptor affinity is consistent with cannabimimetic activity, but there are no controlled human studies defining a characteristic subjective experience or clinical duration.

Reports involving other potent synthetic cannabinoid agonists include anxiety, confusion, agitation, seizures and cardiovascular disturbances. These concerns apply to the broader class; the outcomes have not been confirmed specifically for JWH-398.

Toxicity and research limitations

No well-characterised clinical case series or human metabolism study specific to JWH-398 was identified in the sources reviewed here. Its acute toxic range, dependence potential and long-term effects remain uncertain. Analytical records in forensic databases establish its chemical identity, without showing how often people are exposed or how severe its effects are.

JWH-398 should be distinguished from other chlorinated JWH analogues by the location of the chlorine atom. JWH-203 carries chlorine on a phenylacetyl group, whereas JWH-398 has a chlorinated naphthoyl group.

Related compounds

JWH-398 is related to JWH-018, JWH-210, JWH-203 and AM-2201. It is the 4-chloro analogue of the naphthoylindole scaffold.