Side effects
The adverse effects include drowsiness, dizziness, confusion, constipation, anxiety, nausea, blurred vision, restlessness, decreased coordination, dry mouth, shallow breathing, hallucinations, irritability, problems with memory or concentration, tinnitus and trouble urinating. Chlorphenamine produces less sedation than other first-generation antihistamines.A large study on people 65 years old or older, linked the development of Alzheimers disease and other forms of dementia to the "higher cumulative" use of chlorphenamine and other first-generation antihistamines, due to their anticholinergic properties. Pharmacology
Pharmacodynamics
Chlorphenamine acts primarily as a potent H1 antihistamine. It is specifically a potent inverse agonist of the histamine H1 receptor. The drug is also commonly described as possessing weak anticholinergic activity by acting as an antagonist of the muscarinic acetylcholine receptors. The dextrorotatory stereoisomer, dexchlorpheniramine, has been reported to possess Kd values of 15 nM for the H1 receptor and 1,300 nM for the muscarinic acetylcholine receptors in human brain tissue. The smaller the Kd value, the greater the binding affinity of the ligand for its target. In addition to acting as an inverse agonist at the H1 receptor, chlorphenamine has been found to act as a serotonin reuptake inhibitor (Kd = 15.2 nM for the serotonin transporter). It has only weak affinity for the norepinephrine and dopamine transporters (Kd = 1,440 nM and 1,060 nM, respectively).
Phthisis bulbi is a shrunken, non-functional eye. It may result from severe eye disease, inflammation or injury, or it may represent a complication of eye surgery. Treatment options include insertion of a prosthesis, which may be preceded by enucleation of the eye. Symptoms
The affected eye is shrunken, and has little to no vision. The intraocular pressure in the affected eye is very low or nonexistent. The layers in the eye may be fused together, thickened, or edematous. The eyelids may be glued shut. The eye may be soft when palpated. Under a microscope there may be deposits of calcium or bone, and the cornea is often affected by cataracts. Causes
It can be caused by injury, including burns to the eye, or long-term eye disease or inflammation. End-stage glaucoma can cause it. It can often complicate eye surgery. Other common causes include cancer, retinal detachment, vascular lesions, infection, and inflammation. Treatment
Treatment for the affected eye is often futile. Usually, treatment is to end the pain in the affected eye and for cosmetic purposes, not to restore vision. It can be removed, a procedure called enucleation of the eye. Sometimes, though, it is possible to transplant only parts of the eye, and some vision can be restored. References


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