comfrey

Action and Spectrum

Actions and Spectrum: 

comfrey is recognized for its demulcent properties, which help to soothe and protect irritated tissues. It also has mild astringent properties, which can help tighten and tone tissues. comfrey is often used topically as a poultice or in creams for its emollient and anti-inflammatory properties, which can help reduce inflammation and promote wound healing.  

Regarding spectrum, comfrey is commonly used for various skin conditions such as wounds, bruises, sprains, and strains. It is also utilized for its potential benefits in relieving pain associated with arthritis and rheumatism. Additionally, comfrey has been used in traditional herbal medicine for its potential effects on respiratory health and as a digestive aid. However, further research is needed to understand its spectrum of action in these areas entirely. 

Drug Interaction

Adverse Reaction

Frequency not defined 

liver enlargement 

urine output decrease 

 veno-occlusive disease 

abdominal distension  

abdominal pain 

 anorexia 

 lethargy 

Black Box Warning

Black Box Warning:  

Hepatotoxicity 

comfrey contains pyrrolizidine alkaloids that can cause liver toxicity. Hepatotoxicity, including severe liver damage and liver failure, has been reported using comfrey. Using  comfrey products internally or in excessive amounts may increase the risk of hepatotoxicity.

Contraindication / Caution

Contraindication/Caution:  

Internal use: comfrey should not be used internally due to the presence of pyrrolizidine alkaloids, which can be toxic to the liver and may cause hepatotoxicity. 

Pregnancy and lactation: comfrey should be avoided during pregnancy and lactation, as there is limited safety data available and the potential risk of pyrrolizidine alkaloid toxicity to the developing fetus or newborn. 

Liver disease: Individuals with liver disease or impaired liver function should avoid comfrey due to the risk of exacerbating liver damage or hepatotoxicity. 

Children: comfrey should not be used in children, as this population has limited safety and efficacy data. 

Open wounds or broken skin: comfrey should not be applied to open wounds or broken skin, as it may be absorbed systemically and potentially cause toxicity. 

Known allergy or sensitivity: Individuals with a known allergy or sensitivity to comfrey or its constituents should avoid its use. 

Pregnancy / Lactation

Pregnancy warnings:     

Pregnancy category: N/A 

Lactation: Excreted into human milk is unknown 

Pregnancy Categories:         

Category A: Studies that were well-controlled and met expectations revealed no risk to the fetus in either the first or second trimester. 

Category B: There were a lack of studies on pregnant women and no evidence of risk to the fetus in animal experiments.   

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.   

Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.    

Category N: There is no data available for the drug under this category

Pharmacology

Pharmacology: 

comfrey contains several bioactive compounds, including allantoin, rosmarinic acid, and various pyrrolizidine alkaloids, such as symphytine, echimidine, and lycopsamine. Allantoin is a natural compound that has moisturizing and anti-inflammatory properties and is believed to contribute to the wound healing properties of comfrey. 

Pharmacodynamics: 

comfrey’s pharmacodynamics mechanism involves its mucilage content providing a demulcent effect, allantoin promoting wound healing and exfoliation, tannins reducing inflammation and swelling, and its calcium and phosphorus content supporting bone health. However, it should be noted that comfrey contains pyrrolizidine alkaloids that can be hepatotoxic, so caution should be exercised when using comfrey internally, and it is recommended to use comfrey products that are free from pyrrolizidine alkaloids or to avoid internal use altogether. 

Mechanism of Action: Wound healing: Allantoin, a major component of comfrey, is believed to promote wound healing by stimulating cell proliferation, collagen synthesis, and tissue regeneration. It is also thought to have anti-inflammatory effects, which may help reduce inflammation at the wound site. 

Anti-inflammatory effects: Rosmarinic acid, found in comfrey, has been shown to possess anti-inflammatory properties.This may help reduce inflammation in skin conditions, such as dermatitis and eczema. 

Analgesic effects: comfrey has been traditionally used topically for pain relief. It is believed that comfrey may exert its analgesic effects by reducing inflammation and modulating pain signaling pathways. 

Mucilage properties: comfrey contains mucilage, a type of complex carbohydrate that forms a gel-like substance when it comes into contact with water. Mucilage may have emollient properties, helping to soothe and moisturize the skin.

Pharmacokinetics: 

Absorption 

comfrey can be absorbed through various routes, including oral ingestion, topical application, and inhalation. When taken orally, comfrey is absorbed in the gastrointestinal tract, and its absorption can be influenced by factors such as formulation, dosage, and presence of other substances.  

Distribution 

Once absorbed, comfrey’s constituents, such as allantoin, rosmarinic acid, and pyrrolizidine alkaloids, can distribute throughout the body via the bloodstream. 

Metabolism 

comfrey undergoes metabolism in the liver, where its constituents, including pyrrolizidine alkaloids, may be metabolized into various compounds.  

Elimination and Excretion 

comfrey and its metabolites are eliminated from the body through various routes, primarily via urine and feces.

Adminstartion

Administration:  

Consultation with a Qualified Healthcare Provider: Before using comfrey, it is important to consult with a qualified healthcare provider, such as a physician or a licensed herbalist.  

Internal Use: Internal use of comfrey, such as drinking comfrey tea or taking comfrey supplements, is not recommended due to the potential for liver toxicity.  

External Use: comfrey can be used externally in the form of poultices, salves, or creams. However, it should only be applied to intact skin, and not to open wounds, broken skin, or mucous membranes, as it may be absorbed into the bloodstream and cause systemic effects.  

Patient Information Leaflet

Patient information leaflet 

Generic Name: comfrey 

Why do we use comfrey?  

Herbal medicine: comfrey has been traditionally used in herbal medicine for its purported medicinal properties. It contains compounds such as allantoin, rosmarinic acid, and mucilage that are believed to have anti-inflammatory, analgesic (pain-relieving), and wound healing properties.  

Skin care: comfrey is believed to promote skin health and has been used in cosmetic and skincare products. It is thought to have moisturizing, soothing, and anti-aging properties, and is used in creams, lotions, and ointments for various skin conditions, such as dry skin, eczema, and dermatitis.