Parlodel

Action

Directly stimulates dopamine receptors in hypothalamus, causing release of prolactin-inhibitory factors and thereby relieving akinesia, rigidity, and tremors associated with Parkinson's disease. Also restores testicular or ovarian function and suppresses lactation. Cycloset's action in glycemic control is unknown.

Availability

Capsules: 5 mg

Tablets: 0.8 mg, 2.5 mg

Indications and dosages

➣ Parkinson's disease

Adults: Initially, 1.25 mg P.O. b.i.d. Increase by 2.5 mg/day q 14 to 28 days depending on therapeutic response. Usual therapeutic dosage is 10 to 40 mg/day.

➣ Acromegaly

Adults: Initially, 1.25 to 2.5 mg/day P.O. for 3 days. Increase up to 1.25 to 2.5 mg/day q 3 to 7 days. Usual therapeutic dosage is 20 to 30 mg/day; not to exceed 100 mg/day.

➣ Hyperprolactinemia

Adults: Initially, 1.25 to 2.5 mg/day P.O. Increase gradually q 3 to 7 days up to 2.5 mg two to three times daily.

➣ Neuroleptic malignant syndrome

Adults: Initially, 5 mg P.O. once daily. Increase up to 20 mg/day.

➣ Pituitary tumors

Adults: Initially, 1.25 mg P.O. b.i.d. to t.i.d. Adjust dosage gradually over several weeks to a maintenance dosage of 10 to 20 mg/day given in divided doses.

➣ Type 2 diabetes mellitus

Adults: Initially, 0.8 mg P.O. daily within 2 hours of awakening; may increase by one tablet (0.8 mg) weekly until target range (1.6 to 4.8 mg) or maximal tolerance is reached.

Contraindications

• Hypersensitivity to drug, its components, or other ergot-related drugs

• Severe peripheral vascular disease

• Uncontrolled hypertension, syncopal migraines

• Breastfeeding

Precautions

Use cautiously in:

• impaired hepatic or cardiac function, renal disease, hypertension, pituitary tumor

• psychiatric disorders

• galactose intolerance, severe lactose deficiency, glucose-galactose malabsorption (use not recommended)

• Concomitant use with anti-hypertensives

• Concomitant use with dopamine antagonists such as neuroleptic agents (use not recommended)

• pregnant patients

• children younger than age 15.

Administration

• Give with meals or milk.

• If desired, give at bedtime to minimize dizziness and nausea.

• For Cycloset, administer within 2 hours of patient's waking in the morning and with food.

Adverse reactions

CNS: asthenia, confusion, headache, dizziness, fatigue, delusions, nervousness, mania, insomnia, nightmares, seizures, cerebrovascular accident

CV: hypotension, palpitations, extrasystoles, syncope, arrhythmias, bradycardia, acute myocardial infarction

EENT: blurred vision, diplopia, burning sensation in eyes, amblyopia, rhinitis, sinusitis, nasal congestion

GI: dyspepsia, nausea, vomiting, diarrhea, constipation, abdominal cramps, anorexia, dry mouth, GI hemorrhage

GU: urinary incontinence, polyuria, urinary retention

Musculoskeletal: leg cramps

Skin: urticaria, coolness and pallor of fingers and toes, rash on face and arms, alopecia

Other: metallic taste, digital vasospasm (in acromegaly use only), infection

Interactions

Drug-drug. Amitriptyline, estrogens, haloperidol, hormonal contraceptives, imipramine, loxapine, MAO inhibitors, phenothiazines, progestins, reserpine: interference with bromocriptine effects

Cyclosporine: inhibition of cyclosporine metabolism, leading to cyclosporine toxicity

Dopamine receptor antagonists (such as neuroleptics [including phenothiazines, butyrophenones, thioxanthenes]), metoclopramide: diminished effectiveness of Cycloset and these drugs

Ergot-related drugs: increased ergotrelated adverse reactions, such as nausea, vomiting, and fatigue; decreased effectiveness of these drugs

Erythromycin: increased bromocriptine blood level and greater risk of adverse effects

Levodopa: additive effects of bromocriptine

Potent CYP3A4 inhibitors or inducers, substrates of CYP3A4 (such as azole antimycotics, HIV protease inhibitors): increased or decreased Cycloset circulating levels

Risperidone: increased prolactin blood level, interference with bromocriptine effects

Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, blood urea nitrogen, creatine kinase, growth hormone, uric acid: increased levels

Drug-herbs. Chaste tree fruit: decreased bromocriptine effects

Drug-behaviors. Alcohol use: disulfiram-like reaction

Patient monitoring

• Monitor blood pressure to detect hypotension.

• When giving drug for hyperprolactinemia, monitor serum prolactin.

• When giving drug for acromegaly, monitor growth hormone levels to help guide dosage adjustment.

• When giving drug for diabetes mellitus, monitor blood glucose and hemoglobin A1C levels.

• In long-term use, monitor respiratory, hepatic, cardiovascular, and renal function.

Patient teaching

• Instruct patient to take Cycloset within 2 hours of waking in the morning and with food.

☞ Caution patient not to drink alcohol because of risk of severe reaction.

• Advise patient to have regular dental exams. Drug causes dry mouth, possibly resulting in caries and periodontal disorders.

• To minimize constipation, instruct patient to exercise regularly, increase dietary fiber intake, and drink plenty of fluids (3,000 ml daily).

• Advise patient who doesn't desire pregnancy to use reliable contraceptive, because drug may restore fertility.

• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above.