Varenicline

INTRODUCTION

Indications

Treatment of smoking cessation; in conjunction with nonpharmacologic support (educational materials/counseling).

Action

Selectively binds to alpha₄ beta₂ nicotinic acetylcholine receptors, acting as a nicotine agonist; prevents the binding of nicotine to receptors. Therapeutic Effects: ↓ desire to smoke.

Adverse Reactions/Side Effects

CNS: ↓ attention span, anxiety, depression, insomnia, irritability, dizziness, restlessness, abnormal dreams, agitation, aggression, amnesia, disorientation, dissociation, migraine, psychomotor hyperactivity, suicidal thoughts/behaviors. CV: syncope. GI: diarrhea, gingivitis, nausea, ↑ appetite, constipation, dyspepsia, dysphagia, enterocolitis, eructation, flatulence, gallbladder disorder, GI bleeding, ↑ liver function tests, vomiting. Derm: flushing, hyperhidrosis, acne, dermatitis, dry skin. Hemat: anemia. MS: arthralgia, back pain, musculoskeletal pain, muscle cramps, myalgia, restless legs. Misc: chills, fever, hypersensitivity, mild physical dependence.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Be alert for signs of depression or suicidal behaviors and ideology. Notify physician immediately if patient exhibits these signs.

• Watch for signs of anemia, including unusual fatigue, shortness of breath with exertion, bruising, and pale skin. Notify physician immediately if these signs occur.

• Monitor signs of hypersensitivity reactions, including pulmonary symptoms (tightness in the throat and chest, wheezing, cough, dyspnea) or skin reactions (rash, pruritus, urticaria). Notify physician if these reactions occur.

• Monitor anxiety, irritability, restlessness, agitation, decreased attention, increased aggression, hyperactivity, and other alterations in mood or behavior. Notify physician promptly if these symptoms develop.

• Assess any joint pain, back pain, or muscle pain/cramps to rule out musculoskeletal pathology; that is, try to determine if pain is drug induced rather than caused by anatomic or biomechanical problems.

• Assess dizziness and syncope that might affect gait, balance, and other functional activities (See Appendix C). Report balance problems and functional limitations to the physician, and caution the patient and family/caregivers to guard against falls and trauma.

Interventions

• Help patient explore nonpharmacologic methods to quit smoking (counseling, support groups, and so forth).

Patient/Client-Related Instruction

• Instruct patient to report other side effects such as severe or prolonged headache, sleep loss, restless legs, chills, fever, skin reactions (dermatitis, acne, flushing, increased sweating, dry skin), or GI problems (nausea, vomiting, diarrhea, constipation, indigestion, difficulty swallowing, abdominal pain, belching, flatulence).

Pharmacokinetics

Absorption: 100% absorbed following oral administration.

Distribution: 24 hr.

Metabolism and Excretion: Minimally metabolized; 92% excreted in urine unchanged.

Half-life: 24 hr.