VARENICLINE

VARENICLINE
(var-en'i-cline)
Chantix
Classifications: smoking deterrent agent; nicotinic partial agonist;
Therapeutic:smoking cessation agent; nicotinic receptor agonist
Prototype: Nicotine
Pregnancy Category: C

Availability

0.5 mg, 1 mg capsules

Action

Nicotine increases dopamine release in the brain and cravings for nicotine are stimulated by low levels of dopamine during periods of abstinence. Varenicline is a partial agonist at nicotinic acetylcholine receptors (nAChRs), the sites responsible for the dopamine effects of nicotine. It partially stimulates these receptors to produce a modest level of dopamine but blocks nicotine from binding to many of the nicotinic receptor sites.

Therapeutic Effect

Varenicline binds to nicotinic receptors more potently than nicotine itself. By blocking these receptors, it reduces effects of nicotine in cases where patient relapses and uses tobacco.

Uses

Adjunct for smoking cessation in patients experiencing nicotine withdrawal.

Contraindications

Pregnancy (category C), lactation. Safe use in children or adolescents <18 y is not known.

Cautious Use

Renal disease, impaired renal function, renal failure, older adults.

Route & Dosage

Smoking Cessation
Adult: PO Begin with 0.5 mg/d for 3 d, increase to 0.5 mg b.i.d. for 4 d, then increase to 1 mg b.i.d. on day 8. Treatment duration is 12 wk and may be repeated an additional 12 wk.

Renal Impairment
Cl_cr ≤50 mL/min: titrate to 0.5 mg b.i.d. (max)

Administration

Oral

Give after a meal with a full glass of water.
Dose titration over 8 d (from 0.5 mg to 2 mg daily) is recommended to minimize adverse effects.
Store at 15°–30° C (59°–86° F).

Adverse Effects (≥1%)

Body as a Whole: Fatigue, flushing, gingivitis, headache, influenza-like symptoms, lethargy, malaise, thirst. CNS: Abnormal dreams, anorexia, anxiety, asthenia, disturbance in attention, depression, dizziness, drowsiness, emotional lability, insomnia, irritability, nightmares, restlessness, sensory disturbance, sleep disorder. CV: Chest pain, hypertension. GI: Abdominal pain, constipation, diarrhea, dyspepsia, flatulence, gastroesophageal reflux, nausea, vomiting. Metabolic: Abnormal liver function test, appetite stimulation, weight gain. Musculoskeletal: Arthralgia, back pain, muscle cramps, musculoskeletal pain, myalgia. Respiratory: Dyspnea, epistaxis, respiratory disorder, rhinorrhea. Skin: Hyperhidrosis, pruritus, rash. Special Senses: Dysgeusia, xerostomia. Urogenital: Menstrual irregularity, polyuria.

Interactions

Drug: Cimetidine increases systemic exposure to varenicline by 29%.

Pharmacokinetics

Absorption: Complete absorption from GI tract. Peak: 3–4 h. Distribution: <20% protein bound. Metabolism: Minimal. Elimination: Primarily eliminated unchanged in the urine. Half-Life: 24 h.

Nursing Implications

Assessment & Drug Effects

Monitor smoking cessation behavior and adverse effects.
Monitor BP for new-onset hypertension.
Monitor diabetics for loss of glycemic control.

Patient & Family Education

Follow directions for taking the drug (see Administration).
Report persistent nausea, vomiting, or insomnia to a health care provider.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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