Nicotine

Introduction Overview

Generic Name

Nicotine

Brand Name

Commit
Nicoderm CQ
Nicorette
Nicotrol Inhaler
Nicotrol NS

Dosage Form

Buccal (lozenges and chewing gum)
Topical (transdermal system)
Intranasal (metered spray)
Oral inhalation (nicotine inhaler)

Drug Class

Smoking Cessation Agents
Smoking Deterrents
Deterrents, Smoking

Pharmacokinetics

Absorption:
Nicotine is readily absorbed through multiple routes: transmucosally via chewing gum, lozenges, oral inhalation, and intranasal administration; percutaneously via transdermal patches; but minimally from the gastrointestinal tract due to extensive first-pass metabolism. Absorption efficiency varies by formulation — about 53–55% for gum with peak plasma concentrations reached within 25-30 minutes, approximately 68–98% for transdermal systems reaching peak levels in 2–10 hours, around 53% for intranasal sprays with peak levels in 4–15 minutes, and approximately 60% for oral inhalation with peak concentrations within 15–30 minutes. Notably, acidic beverages reduce buccal absorption by transiently lowering salivary pH. Plasma nicotine levels achieved with gum approximate those from cigarette smoking, whereas transdermal patches produce generally lower and less fluctuating plasma levels. Factors such as common cold or rhinitis may reduce intranasal absorption, and obesity can decrease peak levels and overall exposure from transdermal systems.

Distribution:
After systemic entry, nicotine is distributed rapidly into most body tissues, notably concentrating in the cerebral cortex and adrenal medulla due to its lipophilicity and ability to cross biological membranes. Distribution studies in animals reveal lower concentrations in spleen, adrenal cortex, kidney, and pancreas, reflecting tissue-specific affinities. Nicotine readily crosses the placenta exposing the fetus and is secreted into breast milk, posing potential risk during pregnancy and lactation. Plasma protein binding is low (<5%), allowing free diffusion into tissues.

Metabolism:
Nicotine is extensively metabolized predominantly in the liver through multiple enzymatic pathways, largely by cytochrome P450 2A6, producing more than 20 primarily inactive metabolites, including cotinine which is used as a biomarker for nicotine exposure. This rapid and extensive metabolism contributes to a short plasma half-life and limits systemic exposure. Hepatic impairment can reduce nicotine clearance, necessitating cautious use.

Elimination:
Excretion occurs mainly via the kidneys, primarily as metabolites (70–90%) and a minor fraction as unchanged drug (10–30%). The elimination half-life is biphasic, with an average terminal half-life of approximately 2 hours (range 1–4 hours). After removal of transdermal systems, an apparent longer half-life of 3–6 hours is observed, reflecting continued absorption from skin reservoirs. Renal impairment may reduce clearance, hence dosage adjustment might be required in severe renal dysfunction.

Dosage Forms

Available Dosage Forms:
Nicotine is available in multiple formulations tailored for smoking cessation intervention:
- Buccal (transmucosal): Nicotine polacrilex chewing gum (2 mg and 4 mg strengths), nicotine polacrilex lozenges (2 mg and 4 mg strengths).
- Topical: Transdermal nicotine systems (7 mg/24 hours, 14 mg/24 hours, 21 mg/24 hours).
- Intranasal: Metered dose spray delivering 0.5 mg nicotine per spray.
- Oral inhalation: Nicotine inhaler cartridges delivering up to 4 mg per cartridge.

Dosages for Adults and Adolescents:
Smoking cessation dosages are highly individualized based on smoking intensity:
- Chewing Gum: For patients smoking fewer than 25 cigarettes daily, 2 mg gum every 2 hours during weeks 1–6, tapering over 12 weeks; for ≥25 cigarettes daily, 4 mg gum with similar schedule. Maximum 2 pieces per hour (maximum 24 pieces/day for clinician supervision).
- Lozenges: 2 mg or 4 mg lozenges every 1–2 hours for initial 6 weeks, decreasing frequency over 12 weeks; not to exceed 20 lozenges daily or 5 lozenges in 6 hours.
- Transdermal Patch: For ≤10 cigarettes/day, 14 mg patch daily for 6 weeks then taper; for >10 cigarettes/day, 21 mg patch daily for 4–6 weeks, then 14 mg for 2 weeks, and 7 mg for 2 weeks.
- Intranasal Spray: 1–2 sprays in each nostril per hour initially (1–2 mg/hour), up to a maximum of 5 sprays per nostril per hour; maximum of 80 sprays daily.
- Oral Inhaler: 6–16 cartridges daily for up to 12 weeks, followed by gradual taper over subsequent weeks.

Specific Patient Populations:
No distinct dosage modifications specified currently for special populations, though caution is advised in hepatic and renal impairment due to altered clearance. Pediatric safety and efficacy have not been established; usage in pregnancy only if benefits outweigh risks and after behavioral interventions. Elderly patients require cautious dosing considering age-related physiological changes. Transdermal formulations should be applied to non-irritated skin and nasal spray avoided in those with chronic nasal conditions.

Mechanism Of Action

Nicotine exerts its pharmacologic effects primarily as a ganglionic (nicotinic) cholinergic receptor agonist with stereospecific binding to nicotinic acetylcholine receptors located in the autonomic ganglia, adrenal medulla, neuromuscular junction, and central nervous system (CNS). Upon binding, nicotine stimulates these receptors leading to both excitatory and modulatory neuronal responses.

At low doses, nicotine induces stimulant effects by activating autonomic ganglia, enhancing neurotransmission in the cerebral cortex resulting in increased alertness, heightened cognitive performance, and respiratory stimulation. This occurs through facilitation of acetylcholine release and subsequent activation of downstream signaling cascades. Higher doses engage the mesolimbic dopaminergic system, eliciting reward and reinforcing behavior primarily via dopaminergic neurons within the nucleus accumbens, contributing to addiction potential. The initial ganglionic stimulation is rapidly followed by receptor desensitization and inhibition of neurotransmission, which modulates the net stimulatory effect depending on dose and duration.

Nicotine also activates multiple neurohormonal pathways, triggering release of neurotransmitters and hormones including acetylcholine, norepinephrine, dopamine, serotonin, vasopressin, beta-endorphin, growth hormone, and adrenocorticotropic hormone (ACTH). Cardiovascular effects stem from sympathetic ganglia stimulation and adrenal catecholamine release, causing increased heart rate, myocardial contractility, cardiac output, and peripheral vasoconstriction. Conversely, excessive doses may induce hypotension due to complex autonomic effects.

Gastrointestinal effects are mediated through cholinergic stimulation of smooth muscle tone and motility, often explaining symptoms like nausea and diarrhea with systemic nicotine absorption. Chronic exposure leads to pharmacodynamic tolerance and physical as well as psychological dependence due to receptor desensitization and adaptive changes in neural circuits. Comparison with other smoking cessation pharmacotherapies such as varenicline reveals nicotine acts as a full agonist at nicotinic receptors, whereas varenicline is a partial agonist providing both agonism and receptor blockade.

Clinical studies underpin nicotine replacement therapy's utility in mitigating withdrawal symptoms by providing controlled nicotine levels, reducing the reinforcing feedback from tobacco smoke while allowing gradual cessation supported by behavioral therapies.

Pharmacological Actions

Acts as a ganglionic (nicotinic) cholinergic receptor agonist stimulating autonomic ganglia and CNS neurons.
Exhibits both stimulant and depressant effects on central and peripheral nervous systems depending on dose.
Facilitates neurotransmitter release including dopamine, acetylcholine, norepinephrine, serotonin, and others.
Induces cardiovascular stimulation via sympathetic ganglia activation causing increased heart rate and blood pressure.
Stimulates gastrointestinal motility via cholinergic pathways resulting in increased tone and activity.
Produces behavior-reinforcing effects through mesolimbic dopaminergic system contributing to nicotine addiction.
Leads to development of tolerance and physical dependence with chronic use.
Produces neurohormonal activation affecting multiple hormonal pathways including ACTH and growth hormone release.
Modulates cognitive performance and alertness at low doses through cerebral cortex stimulation.
Can cause peripheral vasoconstriction mediated by sympathetic activation.
Induces both peripheral and central nervous effects such as headache, dizziness, and insomnia.

Therapeutic Or Clinical Uses

Aid in smoking cessation through nicotine replacement therapy (NRT) as an adjunct to behavioral modification programs.
Temporary management adjunct in tobacco dependence to reduce withdrawal symptoms.
Used in multiple dosage forms including chewing gum, lozenges, transdermal patches, nasal spray, and inhalers to provide flexible treatment options.
Off-label use for management of ulcerative colitis with transdermal nicotine formulations.
Part of USPHS guideline recommended first-line therapies for tobacco cessation.
Used in self-medication or clinician-supervised cessation therapy.
May act as an oral substitute in behavior modification via chewing gum or lozenges.
Employed to decrease craving and withdrawal symptoms in nicotine-dependent individuals.
Used to improve chances of sustained abstinence from smoking with appropriate dosing and tapering protocols.
Formulations designed to provide controlled nicotine levels mimicking smoking to reduce relapse.
May be used in combination (e.g., patch plus buccal form) for patients failing single modality therapy.

Side Or Adverse Effects

Gastrointestinal disturbances including nausea, vomiting, dyspepsia, hiccups, and diarrhea.
Oral mucosal irritation, ulceration, jaw-muscle ache, dental issues such as loosening of restorations with chewing gum.
Local skin reactions at transdermal patch sites such as pruritus, erythema, and burning sensation.
Respiratory irritation with nasal spray (runny nose, sneezing, watery eyes, cough) and oral inhaler (oropharyngeal irritation, cough).
Central nervous system effects including headache, dizziness, lightheadedness, insomnia, and nervousness.
Cardiovascular symptoms such as palpitations, increased heart rate, and in rare cases arrhythmias.
Rare allergic reactions including urticaria and rash particularly with transdermal formulations.
Persistent sore throat, mouth problems with lozenge and gum use.
Rare but serious nicotine toxicity presenting with symptoms like hypersalivation, mental confusion, and weakness.
Potential for nicotine dependence and withdrawal symptoms upon discontinuation.
Mild to moderate nasal mucosa irritation and possible exacerbation of chronic nasal disorders.
Possible exacerbation of bronchospasm in patients with reactive airway diseases.
Hyperinsulinemia and insulin resistance with prolonged use could aggravate diabetes.
Delayed healing of peptic ulcers and possible aggravation of hypertension.
Rare risk of contact sensitization leading to serious skin reactions upon re-exposure.

Precautions

Do not use in patients with known hypersensitivity to nicotine or product components, including menthol in inhalers.
Avoid nicotine polacrilex gum in patients with temporomandibular joint disease due to risk of jaw complications.
Use transdermal patches cautiously in patients with dermatologic conditions; rotate sites and monitor for skin reactions.
Intranasal nicotine not recommended in patients with chronic nasal disorders such as allergy or rhinitis.
Exercise caution in patients with coronary heart disease, arrhythmias, or vasospastic disorders; carefully evaluate benefit versus risk.
Avoid in immediate post-myocardial infarction period, serious arrhythmias, or unstable angina unless supervised by clinician.
Use caution in patients with hypertension, hyperthyroidism, pheochromocytoma, and insulin-dependent diabetes due to potential metabolic effects.
Monitor closely for signs of nicotine toxicity; discontinue therapy if symptoms of overdose develop.
Gradually taper use after 2–3 months to reduce risk of nicotine dependence transference.
Avoid simultaneous smoking or usage of other nicotine-containing products to reduce risk of overdose.
Pregnancy category D: use only if benefits justify potential fetal risk and after behavioral interventions fail.
Advise lactating women regarding transfer into breast milk and risk-benefit considerations.
Keep nicotine products out of reach of children and pets to prevent accidental poisoning or fatal ingestion.
Monitor in patients with hepatic or renal impairment due to altered pharmacokinetics.
Avoid acidic beverages 15 minutes before and during use of buccal nicotine forms to optimize absorption.

Warnings

Risk of nicotine toxicity presenting as nausea, vomiting, abdominal pain, dizziness, mental confusion, and weakness.
Potential for addiction and dependence on nicotine replacement products; caution with prolonged use.
Use during pregnancy only if benefits of smoking cessation outweigh fetal risk; nicotine crosses placenta.
Possible exacerbation of bronchospasm; intranasal nicotine contraindicated in severe reactive airway disease.
Cardiovascular effects including increased heart rate and blood pressure; discontinue if arrhythmias occur.
Transdermal systems may cause serious skin sensitization and contact dermatitis; discontinue if severe reaction occurs.
Nicotine withdrawal symptoms such as irritability, anxiety, and sleep disturbances expected on cessation of therapy.
Potential for increased risk of malignant hypertension in patients with accelerated hypertension; monitor closely.
Risk of choking in children if oral inhalers are swallowed; keep out of reach.
Discontinue nicotine polacrilex lozenges or gum if severe mouth, throat, or dental problems develop.
Intranasal spray may cause nasal mucosal irritation, may become less bothersome with continued use.
Safety of therapy continuing beyond 12 weeks not established; discontinue or reassess if longer use required.
Avoid concurrent exposure to nicotine products during therapy to prevent overdose.
Contact with eyes after handling patches may increase percutaneous absorption and should be avoided.
Monitor closely for cardiovascular side effects in patients with histories of coronary artery disease.

Contraindication

Known hypersensitivity or allergic reaction to nicotine or any ingredient in the product formulation.
Hypersensitivity to menthol in nicotine oral inhalers.
Use of nicotine polacrilex gum in patients with temporomandibular joint disorders (TMJ disease).
Severe reactive airway disease contraindicates intranasal nicotine spray use.
Current smokers should not self-medicate with nicotine replacement therapies to avoid nicotine overdose.
Patients with acute myocardial infarction or serious arrhythmias in the immediate post-event period unless supervised.
Known intolerance or allergy to excipients such as aspartame in nicotine lozenges (phenylketonurics).
Known severe skin disorders sensitive to adhesive patches in the site of transdermal application.
Children and pets due to risk of accidental poisoning.
Patients who continue smoking or using other nicotine-containing products during therapy without medical supervision.

Drug Interactions

Nicotine and cigarette smoke induce hepatic enzymes, altering metabolism of concomitant drugs.
Smoking cessation alters drug metabolism, potentially increasing blood levels of drugs such as acetaminophen, caffeine, theophylline, and tricyclic antidepressants.
Potential pharmacodynamic interactions with sympathomimetic and sympatholytic drugs may require dose adjustments.
Drugs producing cutaneous vasoconstriction or vasodilation may affect transdermal nicotine absorption.
Acidic beverages like coffee and carbonated drinks decrease buccal nicotine absorption; avoid 15 minutes before and during nicotine polacrilex use.
Smoking cessation may alter plasma catecholamine levels affecting adrenergic agonist and antagonist therapies.
Interactions with beta-adrenergic blockers such as propranolol involve altered metabolism and restored cardiac output.
Bupropion may increase risk of hypertension when given concomitantly with transdermal nicotine.
Furosemide diuretic effects may increase after smoking cessation.
Nicotine may delay time to peak plasma concentration of nasal vasoconstrictors like xylometazoline.
Smoking cessation may increase blood levels of oxazepam, pentazocine, propoxyphene, requiring dosage adjustment.
Insulin sensitivity changes occur upon smoking cessation; adjust insulin dosage with close blood glucose monitoring.
Smoking cessation may reduce absorption of glutethimide.
Careful monitoring and dose adjustment of sympathomimetic and sympatholytic agents are advised during therapy.
Nicotine replacement may interact with herbal and OTC supplements altering efficacy or side effect profiles.

Preparations Of The Drug

Nicotine Nasal Spray Solution: 0.5 mg per metered spray; brand name Nicotrol NS by Pfizer.
Nicotine Oral Inhalation Cartridge: 4 mg per cartridge; brand name Nicotrol Inhaler by Pfizer.
Transdermal Nicotine Systems (patches): 7 mg/24 hours (Step 3), 14 mg/24 hours (Step 2), and 21 mg/24 hours (Step 1), brand name NicoDerm CQ by GlaxoSmithKline.
Buccal Nicotine Polacrilex Lozenge: 2 mg and 4 mg strengths; brand names Commit and Nicotine Polacrilex Lozenge by GlaxoSmithKline.
Buccal Nicotine Polacrilex Chewing Gum: 2 mg and 4 mg strengths; brand names Nicorette and Nicorette DS by GlaxoSmithKline.
All transdermal patches are available in protective pouches, requiring application to clean, dry, hairless skin.
Oral inhaler cartridges are designed for single use with a mouthpiece and require storage under 30°C protected from light.
Intranasal spray pumps require priming prior to initial use, capable of delivering 100 doses per container.
Lozenges and gum formulations contain flavoring agents such as mint, cinnamon, or orange to improve acceptability.
Commit lozenges contain aspartame, providing phenylalanine — caution in phenylketonuria.
All nicotine products must be kept out of reach of children and pets; used products should be disposed safely to prevent accidental ingestion.
Specific excipient profiles vary by manufacturer and preparation; consult product labeling for clinical considerations.
Products are supplied by multiple pharmaceutical manufacturers including Pfizer and GlaxoSmithKline.
Dose titration and tapering are recommended according to individual nicotine dependence and treatment response with close clinical monitoring.
Manufacturers recommend storage at controlled room temperature ranges, generally between 20–30°C, with protection from light and moisture.