What is Tetracaine?
Tetracaine is a type of amino ester local anaesthetic, which has a longer duration of action than benzocaine and lidocaine. It was released for medical use in 1941 and was hailed by the World Health Organization as 1 of the most effective and safe medicines needed in a health system. Local anaesthetics can be used for topical applications to numb the conjunctiva, skin, eardrum, and mucous membrane. Nowadays, it is rarely used for epidural anaesthesia or peripheral nerve blocks due to slow onset, potential toxicity in high doses, and profound motor blockade.
Tetracaine comes in a 0.5%, 1%, and 2% solution or as Niphanoid crystals. The crystal form is preferred because of the relative instability of tetracaine. A solution with 0.5% tetracaine hydrochloride is used as an ophthalmic solution for procedures requiring a rapid and short-acting topical anaesthesia.
Mechanism of Action
Tetracaine induces local anaesthesia by reversibly blocking the condu ...
What is Synvisc?
It is a sterile, apyrogenic, viscoelastic solution containing hylans or hyaluronic acid (HA) derivatives for the treatment of knee pain and joint inflammation associated with osteoarthritis (OA). It contains both Hylan A and Hylan B in buffered physiological sodium chloride. Synvisc is only approved FDA for intra-articular injection of the knee. It is being used off-label for other OA-affected joints such as the hips, ankles, and shoulders.
Composition and Characteristics
The active ingredients of Synvisc, Hylan A and B, are made from a type of hyaluronan that is extracted from rooster combs. This naturally occurring substance is also found in large amounts in the human body, particularly in joints, where it acts as a lubricant and shock absorber to help the joints function properly. Hylans are absorbed by the body through the same pathway that degrades hyaluronan. The metabolites produced from Hylan degradation are non-toxic.
Usage of Synvisc
As a temporary r ...
What is Blepharospasm?
Blepharospasm is a progressive neurological condition characterised by abnormal, involuntary contractions and spasms of the eyelids. The term can be applied to any abnormal twitching of blinking of the eyelid, regardless of the underlying causes. Secondary blepharospasm is associated with another condition or syndrome, such as dry eyes, tardive dyskinesia, or Tourette’s syndrome. It must be differentiated from Benign Essential Blepharospasm (BEB), a type of focal cranial dystonia that involves increased contraction of the eyelid muscles leading to involuntary eyelid closure. Despite having normal eyes, patients with BEB may experience visual disturbances or blindness due to the forced closure of the eyelids.
Early Stage Symptoms:
Blepharospasm symptoms may start gradually, beginning with eye irritation or increased blink rate. In the early stages, it is often triggered by precipitating irritants or stressors, including fatigue, corneal or eyelid irrit ...