It is a tetracyclic piperazine-azepine.Mirtazapine has antihistamine, α2-blocker, and antiserotonergic activity. It is specifically a potent antagonist or inverse agonist of the α2A-, α2B-, and α2C-adrenergic receptors, the serotonin 5-HT2A, 5-HT2C, and the histamine H1 receptor. Unlike many other antidepressants, it does not inhibit the reuptake of serotonin, norepinephrine, or dopamine, nor does it inhibit monoamine oxidase. Similarly, mirtazapine has weak or no activity as an anticholinergic or blocker of sodium or calcium channels, in contrast to most TCAs. In accordance, it has better tolerability and low toxicity in overdose. As an H1 receptor antagonist, mirtazapine is extremely potent, and is in fact the most potent of all the TCAs and TeCAs. Antagonism of the H1 receptor is by far the strongest activity of mirtazapine, with the drug acting as a selective H1 receptor antagonist at low concentrations.The (S)-(+) enantiomer of mirtazapine is responsible for antagonism of the serotonin 5-HT2A and 5-HT2C receptors, while the (R)-(–) enantiomer is responsible for antagonism of the 5-HT3 receptor. Both enantiomers are involved in antagonism of the H1 and α2-adrenergic receptors, although the (S)-(+) enantiomer is the stronger antihistamine.Although not clinically relevant, mirtazapine has been found to act as a partial agonist of the κ-opioid receptor at high concentrations (EC50 = 7.2 μM). α2-Adrenergic receptor
Antagonism of the α2-adrenergic receptors, which function largely as inhibitory autoreceptors and heteroreceptors, enhances adrenergic and serotonergic neurotransmission, notably central 5-HT1A receptor mediated transmission in the dorsal raphe nucleus and hippocampus; hence, mirtazapines classification as a NaSSA.
Dornase alfa (proprietary name Pulmozyme from Genentech) is a highly purified solution of recombinant human deoxyribonuclease I (rhDNase), an enzyme which selectively cleaves DNA. Dornase alfa hydrolyzes the DNA present in sputum/mucus of cystic fibrosis patients and reduces viscosity in the lungs, promoting improved clearance of secretions. This protein therapeutic agent is produced in Chinese hamster ovary cells. Cystic fibrosis
Dornase alfa is the most recent therapeutic agent developed with this basic mechanism of action. Prior to the cloning of the human enzyme, bovine DNase I was on the market for many years, though its utility was limited by the inherent antigenic response to a cow protein in the lungs of patients. Other DNases, such as DNase II, have therapeutic potential as well, but no further DNases have been brought to market yet for cystic fibrosis. Dornase alfa is an orphan drug. Contraindications
Hypersensitivity to dornase alfa
Hypersensitivity to Chinese hamster ovary cell products

Economy
Dornase alpha 1000 units (1 mg/ml)2.5ml (2500units) = £18.52 (GBP)

Off label use
Dornase alfa has recently been shown to improve lung function in non-cystic fibrosis pre-term infants atelectasis where other therapies have failed.In studies conducted, Dornase alfa has been thought to help resolve mucus secretion in COVID-19 patients as well as in the treatment of cystic fibrosis, but since it is taken with nebulizer in general use and there is a possibility of aerosolization of the virus, it is not preferred in most medical centers to avoid secondary infections. == References ==