pramipexole dihydrochloride

pramipexole dihydrochloride

Pharmacologic class: Non-ergot dopamine agonist

Therapeutic class: Antidyskinetic

Pregnancy risk category C

Action

Unknown. May directly stimulate post-synaptic dopamine receptors in corpus striatum (unlike levodopa, which may increase brain's dopamine concentration).

Availability

Tablets: 0.125 mg, 0.25 mg, 0.5 mg, 0.75 mg, 1 mg, 1.5 mg

Tablets (extended-release): 0.375 mg, 0.75 mg, 1.5 mg, 2.25 mg, 3 mg, 3.75 mg, 4.5 mg

⊘Indications and dosages

➣ Idiopathic Parkinson's disease

Adults: Initially, 0.125 mg P.O. t.i.d.; may increase by 0.125 mg q 5 to 7 days over 6 to 7 weeks. Maintenance dosage ranges from 1.5 to 4.5 mg/day in three divided doses. Or, 0.375 mg (extended-release) P.O. daily; may increase no more frequently than every 5 to 7 days, first to 0.75 mg/day and then by 0.75-mg increments up to a maximum recommended dosage of 4.5 mg/day. Assess therapeutic response and tolerability at a minimal interval of 5 days or longer after each dose increment.

➣ Moderate to severe primary restless leg syndrome

Adults: Initially, 0.125 mg P.O. once daily 2 to 3 hours before bedtime. For patients requiring additional symptomatic relief, increase dosage as needed every 4 to 7 days, up to dosage of 0.5 mg once daily.

Dosage adjustment

• Renal impairment

Contraindications

• Hypersensitivity to drug or its components

Precautions

Use cautiously in:
• renal impairment
• elderly patients
• pregnant or breastfeeding patients
• children (safety not established).

Administration

• Administer extended-release tablets whole.
• Know that patients may be switched overnight from immediate-release tablets to extended-release tablets at the same daily dose; however, dosage adjustment may be needed in some patients.
• Don't give at same time as other CNS depressants.
• Don't stop therapy abruptly. Taper dosage over 1 week.

Adverse reactions

CNS: headache, dizziness, drowsiness, hallucinations, asthenia, confusion, dyskinesia, insomnia, hypertonia, unsteadiness, sleep attacks, abnormal dreams, amnesia

CV: orthostatic hypotension

EENT: retinal deterioration

GI: nausea, constipation, dyspepsia, dry mouth

GU: urinary frequency, erectile dysfunction

Musculoskeletal: leg cramps

Respiratory: fibrotic complications (such as retroperitoneal fibrosis, pulmonary infiltrates, pleural effusion or thickening)

Skin: rhabdomyolysis (immediate release tablets)

Other: accidental injury, edema

Interactions

Drug-drug.Cimetidine: increased pramipexole blood level

Dopamine antagonists (such as butyro-phenones, metoclopramide, phenothia-zines, thioxanthenes): decreased pramipexole efficacy

Levodopa: increased risk of hallucinations and dyskinesia

Patient monitoring

• Evaluate patient for therapeutic and adverse effects.
• Assess blood pressure; watch for orthostatic hypotension.
• Monitor neurologic status, especially for sleep attacks and extrapyramidal symptoms.
• Watch closely for pulmonary complications.

Patient teaching

• Instruct patient to take drug with food if it causes nausea. Tell him not to take at same time as other CNS depressants.
• Instruct patient to swallow extended-release tablets whole and not to chew, crush, or divide them.
• Advise patient to report respiratory problems, dyskinesia, hallucinations, and sleep attacks.
• Tell patient drug may cause erectile dysfunction. Encourage him to discuss this effect with prescriber.
• Inform patient and family that drug's neurologic and motor effects increase risk of sudden onset of sleep without warning and accidental injury. Teach them ways to prevent injury.

☞ Advise patient and family to contact prescriber if vision changes or unexplained muscle pain, tenderness, or weakness occurs.
• Tell patient to move slowly when sitting up or standing, to avoid dizziness from sudden blood pressure decrease.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs mentioned above.