Interactions
As a MAO inhibitor, safinamide can theoretically cause hypertensive crises, serotonin syndrome and other severe side effects when combined with other MAO inhibitors or with drugs that are known to interact with MAO inhibitors, such as pethidine, dextromethorphan, selective serotonin reuptake inhibitors (SSRIs), serotonin–noradrenaline reuptake inhibitors (SNRIs), tricyclic and tetracyclic antidepressants. An interaction with tyramine, a substance found in various foods, could be expected by the same reasoning but has been excluded in studies.Safinamide should not be given with opioids; some fatal reactions have occurred.Another theoretical interaction is with drugs with affinity to the transporter protein ABCG2 (also known as BCRP), such as pitavastatin, pravastatin, ciprofloxacin, methotrexate, and diclofenac; a study with the latter has shown no clinical relevance. A study testing possible interactions with amidase inhibitors is part of the post-authorisation development plan. There are no relevant interactions related to cytochrome P450 (CYP) liver enzymes, although one inactivation pathway of safinamide seems to be mediated by CYP3A4. Pharmacology
Mechanisms of action
Like the older antiparkinson drugs selegiline and rasagiline, safinamide is a selective monoamine oxidase B inhibitor, reducing degradation of dopamine; in contrast to the other two, its action is reversible. Safinamide also inhibits glutamate release and dopamine and serotonin reuptake. It binds to the sigma receptors as well, with IC50 values for binding inhibition of 19 nM for σ1 and 1,590 nM for σ2. Additionally, it blocks sodium and calcium channels, the relevance of which for its antiparkinson action is however unknown.
Permanent neonatal diabetes mellitus (PNDM) is a newly identified and potentially treatable form of monogenic diabetes. This type of neonatal diabetes is caused by activating mutations of the KCNJ11 gene, which codes for the Kir6.2 subunit of the beta cell KATP channel. This disease is considered to be a type of maturity onset diabetes of the young (MODY). Cause
It can be associated with GCK, KCNJ11, INS, and ABCC8. Diagnosis
This results in congenital impairment of insulin release, although in the past, this was always being thought to be unusually early type 1 diabetes mellitus. The insulin deficiency results in intrauterine growth retardation with birth weight small for gestational age. The diabetes is usually diagnosed in the first 3 months of life due to continuing poor weight gain, polyuria, or diabetic ketoacidosis. Rare cases have been recognized as late as 6 months of age. Treatment
Remarkably, this type of diabetes often responds well to sulfonylureas and insulin may not be necessary. More severe mutations in the KCNJ11 gene can cause early-onset diabetes which does not respond to the sulfonylurea drugs, as well as a syndrome of developmental delay and neurological features called the DEND syndrome. These forms of diabetes are very rare conditions, appearing in about 1/100,000 to 1/200,000 live births, and accounting for about 1/1000 of type 1 diabetes cases.