Scientific Name(s): Lobelia inflata L.
Common Name(s): Herba Lobellae Chinensis, Asthma weed, Bladderpod, Chinese Lobelia , Eyebright, Gagroot, Indian tobacco, Indian weed, Pukeweed, Vomitwort
Medically reviewed by Drugs.com. Last updated on April 21, 2020.
L. inflata and its major alkaloid, lobeline, have been used in smoking cessation programs and have been proposed for treatment of other drug dependencies; however, clinical evidence is limited.
There is no recent clinical evidence to support the use of lobelia. The sale of OTC lobeline products for smoking cessation was prohibited by the US Food and Drug Administration (FDA) in 1993.
Traditional use of the leaf (eg, as an expectorant) suggests 100 mg of dry herb up to 3 times a day. However, there are no clinical trials to support this use. Doses of 0.6 to 1 g leaf are considered toxic, while 4 g of leaf is considered to be fatal.
Contraindications have not been defined; however, the sale of lobelia OTC products for smoking cessation is prohibited by the FDA due to a lack of efficacy and safety evidence.
Avoid use. Documented adverse effects, including loss of uterine tone and lack of safety evidence.
None well documented.
Lobelia and lobeline are capable of inducing nausea, vomiting, tremors, and dizziness at high doses. Lobelia alkaloids are cardioactive, and cardiotoxicities, including hypotension, tachycardia, and convulsion, have been reported. Contact dermatitis has also been reported.
Toxic dosages of the plant have been described: 1 g of leaf is toxic, while 4 g of leaf is considered to be a fatal dose. The alkaloid lobeline was not genotoxic or mutagenic in 1 study, and liver and kidney biochemistry in mice appeared unaffected.
- Campanulaceae (harebell)
L. inflata is a branching, perennial herb that is completely self-fertilizing and reproduces only once in its lifetime.1 It grows from 0.3 to 0.9 m tall and produces small, violet-pinkish flowers in the alternate leaf axils. The base of the flower expands to form the seed capsule, which is the source of the name "inflata." It is native to the eastern half of United States and parts of Canada.2, 3 The genus Lobelia has more than 400 recognized species, some of which contain alkaloids similar to those of L. inflata, including Livistona chinensis, a plant important in traditional Chinese medicine.3
The plant was named in honor of Matthias de Lobel, a 16th century Flemish physician and botanist, and is native to North America. American Indians smoked the leaves like tobacco and used them medicinally for respiratory ailments. Lobelia was introduced into New England medical practice in the 18th century to produce emesis. It was also used in treating colic, rheumatism, fever, and asthma. By the 19th century, lobelia was considered an important medicinal plant used in many conditions (eg, abscess, insomnia, tetanus, shock); however, fatalities were recorded due to dosing inconsistencies.4, 5 In 1993, the sale of lobelia OTC products for smoking cessation was prohibited by the FDA.3, 6, 7
The piperidine alkaloid lobeline was isolated as the main active component of Lobelia in 1921,8 and its absolute stereochemistry was determined in 1965.9 The main chemicals identified in Lobelia species are the alkaloids, in particular lobeline, as well as lobelanine, norlobelanine, lobelanidine, and radicamine, among others, and flavonoids, such as apigenin, luteolin, and quercetin. Other compounds include terpenes, alkynes, coumarins, and mineral elements.10, 11, 12 Lobeline concentration is highest in the seeds of the plant.13 Antiviral activity observed in L. chinensis has been attributed to lobechine and scoparone.14
Uses and Pharmacology
Lobeline has a high affinity for nicotinic acetylcholine receptors, and exhibits both agonist and antagonistic actions.13, 15, 16, 17 However, because a large diversity of nicotinic receptor subtypes have been identified, lobeline's actions are now thought to be only partly caused by agonism at nicotinic receptors, with some subtypes insensitive to lobeline.18, 19, 20 Similarly to nicotine, stimulation of respiration and bronchoconstriction have been observed with lobeline21; however, lobeline exhibits a slow off rate from receptors17 and probably acts via a different mechanism than does nicotine.13, 22 The effects of lobeline on N-methyl-D-aspartate,23 and [3H]5-HT,24 and norepinephrine25 release have been described. A review of potential mechanisms of action has been published.13
Experimental work has provided evidence that lobeline may be useful in the treatment of amphetamine abuse, based on the blockade of amphetamine-induced dopamine release in rat striatum, and the observed high affinity of lobeline for opioid receptors.13, 26 Lobeline attenuated the self-administration of amphetamine, methamphetamine, and heroin by rats.26, 27, 28, 29 In several rodent models, lobeline had a selective effect on amphetamine-induced behavior and neurochemistry.30 Limitations of lobeline may include the observation of self-administration in drug-naive mice,31 although disputed,13 and the fact that cross-tolerance to nicotine has been observed.15
There are no clinical data regarding the use of lobeline or lobelia extracts in management of psychostimulant abuse. The addiction liability of lobeline in humans has not been established.
Experiments in rodents and in vitro studies have produced equivocal results, possibly reflecting a diversity of experimental procedures, as well as actions of lobeline on receptor sites.13, 32, 33, 34
Lobeline was a component of OTC products for smoking cessation for many years. Results from clinical studies of the efficacy of lobeline have been mixed,35, 36, 37 and a meta-review found that none of the available studies were adequately controlled or of sufficient duration to prove its efficacy.38, 39 The FDA required the removal of lobeline products for smoking cessation from the market because of lack of demonstrated efficacy as part of its OTC review process in 1993.6
CNS, other effects
Experiments have shown lobeline to exert analgesic,40, 41 enhanced memory and learning,42, 43 antidepressant,44 and anxiolytic effects.5, 13, 45, 46 Lobeline has also been shown to reduce seizures in mice, possibly by increasing the levels of gamma-aminobutyric acid in the brain.47
A small study (N = 42) evaluated the effect of lobeline in attention deficit hyperactivity disorder (ADHD) compared with placebo and methylphenidate. No discernable difference could be found; however, the small study size could be responsible for the lack of effect.46 There are no clinical data on the use of lobeline in epilepsy.
Lobeline and extracts of L. chinensis have been studied in vitro and in rodents for anticancer activity. In mice, an extract of L. chinensis inhibited growth of liver and gastric cancers12 and reduced the number of precancerous colon lesions.49 In human cancer cell lines, lobeline showed potential in reversing P-glycoprotein transporter–dependent multidrug resistance.50
Lobeline was traditionally used for the management of respiratory conditions, such as pneumonia, asthma, and bronchitis, because it induces coughing and consequent expectorant action.5 With the development of more effective agents, use of lobelia became obsolete. However, a group of researchers reported on the effect of lobeline on juxtapulmonary receptors using intravenous (IV) bolus administrations.51
There is no recent clinical evidence to support the use of lobelia. The sale of OTC lobeline products for smoking cessation was prohibited by the US FDA in 1993.6
A study among patients with ADHD used daily doses of lobeline (salt form undefined) 7.5, 15, and 30 mg for 7 days.46 IV lobeline as a bolus has been used in limited clinical studies at doses of up to 100 mcg/kg (a mean dose of 45 mcg/kg [+/-23 mcg] produced a distinct dry cough).51
Traditional use of the leaf (eg, as an expectorant) suggests 100 mg of dry herb up to a maximum of 3 times a day.7 Doses of 0.6 to 1 g of leaf are considered toxic, while 4 g of leaf is considered to be fatal.7
Pregnancy / Lactation
None well documented.
Lobelia and lobeline are capable of inducing nausea, vomiting, tremors, and dizziness at high doses (lobeline sulfate 8 mg).7 Respiratory effects have also been described; at high doses, lobeline can induce sensations of choking or breathlessness.51, 53 The lobelia alkaloids are cardioactive, and cardiotoxicities, including hypotension, tachycardia, and convulsion, have been reported.54, 55 Death from overdose has been recorded in historical literature; however, reports in the medical literature are lacking.3, 7 In 1993, sale of lobelia OTC products for smoking cessation was prohibited by the FDA due to a lack of efficacy and safety evidence.3, 6, 7, 38 Contact dermatitis has been reported.56
Toxic doses of the plant have been described (1 g of leaf as toxic, while 4 g of leaf is considered to be fatal).7 The alkaloid lobeline was not genotoxic or mutagenic in 1 study,57, 58 and liver and kidney biochemistry in mice appeared unaffected.57, 58
- L. inflata
- Livistona chinensis
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