Pramipexole Dihydrochloride (3 brand names, 2 dosage forms, 1 route)
Available dosage forms: TABLET, TABLET, EXTENDED RELEASE.
Routes of administration: ORAL.
Brand Names
- MIRAPEX
- MIRAPEX ER
- PRAMIPEXOLE DIHYDROCHLORIDE
Contraindications
None.
Adverse Reactions
The following adverse reactions are discussed in greater detail in other sections of the labeling: Falling Asleep During Activities of Daily Living and Somnolence [see Warnings and Precautions (5.1) ] Symptomatic Orthostatic Hypotension [see Warnings and Precautions (5.2) ] Impulse Control/Compulsive Behaviors [see Warnings and Precautions (5.3) ] Hallucinations and Psychotic-like Behavior [see Warnings and Precautions (5.4) ] Dyskinesia [see Warnings and Precautions (5.5) ] Postural Deformity [see Warnings and Precautions (5.6)] Rhabdomyolysis [see Warnings and Precautions (5.8) ] Retinal Pathology [see Warnings and Precautions (5.9) ] Events Reported with Dopaminergic Therapy [see Warnings and Precautions (5.10) ] Withdrawal Symptoms [see Warnings and Precautions (5.11) ]
Mechanism of Action
Pramipexole is a non-ergot dopamine agonist with high relative in vitro specificity and full intrinsic activity at the D2 subfamily of dopamine receptors, binding with higher affinity to D3 than to D2 or D4 receptor subtypes. Parkinson’s Disease The precise mechanism of action of pramipexole as a treatment for Parkinson’s disease is unknown, although it is believed to be related to its ability to stimulate dopamine receptors in the striatum. This conclusion is supported by electrophysiologic studies in animals that have demonstrated that pramipexole influences striatal neuronal firing rates via activation of dopamine receptors in the striatum and the substantia nigra, the site of neurons that send projections to the striatum. The relevance of D3 receptor binding in Parkinson’s disease is unknown. Restless Legs Syndrome (RLS) The precise mechanism of action of pramipexole dihydrochloride tablets as a treatment for RLS is unknown. Although the pathophysiology of RLS is largely unknown, neuropharmacological evidence suggests primary dopaminergic system involvement. Positron Emission Tomographic (PET) studies suggest that a mild striatal presynaptic dopaminergic dysfunction may be involved in the pathogenesis of RLS.
Overdosage
There is no clinical experience with significant overdosage. One patient took 11 mg/day of pramipexole for 2 days in a clinical trial for an investigational use. Blood pressure remained stable although pulse rate increased to between 100 and 120 beats/minute. No other adverse reactions were reported related to the increased dose. There is no known antidote for overdosage of a dopamine agonist. If signs of central nervous system stimulation are present, a phenothiazine or other butyrophenone neuroleptic agent may be indicated; the efficacy of such drugs in reversing the effects of overdosage has not been assessed. Management of overdose may require general supportive measures along with gastric lavage, intravenous fluids, and electrocardiogram monitoring.