Piper methysticum                              Common name: Kava-kava
Family: Piperaceae

Parts used:  Rhizome

Constituents:  Resinous kava lactones (alpha-pyrones) mainly consisting of kavain, dihydrokavain, and methysticin. Chaclones, Nutrients, Flavonoids, Piperidine alkaloid.

Medicinal actions:  Sedative, nervous system & muscle relaxant, anticonvulsant, local anesthetic, analgesic, anti-fungal, anti-spasmodic, anti-depressant, stimulant, mild euphoric, antiseptic, anti-inflammatory, diaphoretic, rubefacient, bitter, carminative, diuretic

Medicinal use:  Reduces anxiety and promotes cognitive function in cases of stress and restlessness. Will aid in insomnia, headaches due to tension, neuralgia, dizziness and depression (may help with benzodiazepine withdrawal). Mild antiseptic diuretic in urinary tract infections and useful also in interstitial cystitis. Any genitourinary tract infection or inflammation may benefit from its use. Can be used internally (and topically) for rheumatism, joint pain, muscle tension, neuralgias, chronic pain and restless leg syndrome.

Pharmacology:  

• Kava lactones (pyrones) are analgesic, anti-depressant, antispasmodic and urinary anesthetics.
• It’s unclear if kava binds GABA receptors. It does not act as a CNS depressant, but helps retain/increase mental functioning.

Pharmacy: Capsules, standardized: 100-200 mg kava lactones/day in divided doses. Dried rhizome:  1.5-3 g/day in divided doses (mixed with saliva first). Decoction: 30g/500ml water, simmer 20 min, 1/2-1 cup TID.  Tincture: (1:2, 45%), 3-6 ml/day in divided doses. Poultice/Lotion: apply topically as needed.

Contraindications:  Operating machinery, or with strong anxiety/depression. Caution with Parkinson’s and in the elderly.

Toxicity: Human studies using kava at therapeutic dosages have failed to demonstrate any toxic effects.  Prolonged use of a dose equivalent to 400 mg or more of kava lactones per day is likely to cause the characteristic skin lesions of kava-kava toxicity (pigmented, dry, covered with scales) which heals upon discontinuance of the kava extract.  At doses greater than 9g per day, liver enzymes can elevate and should be monitored. May cause drowsiness

Interactions: CNS depressants (alcohol, medications), anti-psychotics, barbiturates, benzodiazepine, levodopa, warfarin.

Research:

• A clinical trial demonstrated Kava to be as effective as benzodiazepines to relieve anxiety.