comfrey

Complementary/Alternative Medicine: This monograph describes a natural or herbal product that is not subject to FDA guidelines for medicines. Patients and clinicians are advised to read package labels carefully to ensure safe and efficacious use.

REMS

Topical Applied to peri-wound areas, skin ulcers, fractures, bruises and sprains to stimulate healing

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Oral use. Ascites, hepatosplenomegaly, jaundice, hepatic cirrhosis and necrosis and DEATH can result from veno-occlusive disease. Oral use of comfrey for as little as 5–7 days in a child and 19–45 days in adults have resulted in severe hepatic disease and death;
Pregnancy and lactation;
Allergy to comfrey;
Use on broken skin;
Do not use topical comfrey for more than 4–6 wk per year or >100 mcg/day (see dosing).

Use Cautiously in:

Liver disease.

Adv. Reactions/Side Effects ⬆ ⬇

Toxicities associated with oral use:

Misc: Extended topical use or high concentrations can lead to systemic absorption and cause toxicity

Interactions ⬆ ⬇

Natural-Drug Products:

Phenobarbitaland other hepatotoxic agents can ↑ the risk of hepatotoxicity.

Natural-Natural Products:

Do not use with other pyrrolizidine alkaloid-containing herbs, including: alkanna, borae, Crotolaria spp, gravel root, Heliotropium spp, hemp agrimony, Henecio spp, hound’s tongue, petasites, colt’s foot, and Senecio species plants: dusty miller, alpine ragwort, groundsel, golden ragwort, and tansy ragwort.

Availability ⬆ ⬇

Cream: ^OTC
Ointment: ^OTC
Powder: ^OTC

Route/Dosage ⬆ ⬇

(Adults ): Apply as needed to affected area. Do not apply on broken skin. Daily-applied dosage of pyrrolizidine alkaloids should not exceed 100 mcg, but products are generally not labeled with this information. Do not use for more than 4–6 wk per year.

US Brand Names ⬆ ⬇

Ass ear, black root, blackwort, bruisewort, Consolidae radix, consound, gum plant, healing herb, knitback, knitbone, salsify, slippery root, Symphitum officinale, Symphitum radix, wallwort

Action ⬆ ⬇

Topical Comfrey’s topical healing and anti-inflammatory actions come from the allantoin and rosmaric acid components. Some pyrrolizidine alkaloids have anti-inflammatory activity.
Comfrey contains hepatotoxic and carcinogenic pyrrolizidine alkaloids if taken orally.

Therapeutic effects:

Decreased inflammation.

Classifications ⬆ ⬇

Therapeutic Classification: antiulcer agents, wound/ulcer/decubiti healing agent

Pharmacokinetics ⬆ ⬇

Absorption: Unknown.

Distribution: Unknown.

Metabolism/Excretion: Metabolized by the liver by the cytochrome P450 system.

Half-Life: Unknown.

Time/Action Profile ⬆ ⬇

ROUTE	ONSET	PEAK	DURATION
Topical	unknown	unknown	unknown
PO	Toxic effects in as little as 5 days	unknown	unknown

Patient/Family Teaching ⬆ ⬇

Warn patients that oral consumption has been associated with liver damage and is not recommended.
Topical Use on an open wound is not recommended because absorption is increased with the risk of liver toxicity.
Instruct patient that if signs of redness, tenderness, swelling, pain or wound drainage develop to discontiue use of this herbal supplement and seek attention from a health care provider.
Advise patients that traditional wound healing therapies have shown to be effective and encourage use of FDA approved products for wound healing.
Caution patients that use of this herbal supplement should not extend beyond 4–6 wk at one time or for a total cumulative time of 4–6 wk within the same 12 mo period.
Warn women of child bearing age not to use this agent if pregnant or breastfeeding.

section name header

Indications ⬇