Hyoscine tablets

Calculate the percentage of the stated content of hyoscine hydrobromide in travel sickness tablets from the following data. The assay is carried out in a manner similar to the eyedrop assay described above. The amount of atropine added as an internal standard does not enter into the calculation if we assume that the same amount is added to Solutions 1 and 3. 

Hyoscine crosses the blood-brain barrier more rapidly than atropine, therefore some of the side effects are more pronounced with hyoscine. These include drowsiness, blurred vision, dizziness, dry mouth, and difficulty with micturition, while confusion may occur in the elderly. Efficacy in PONV is only moderate, and it is now rarely used. It is, however, a well-proven remedy for motion sickness, and an effect on the vestibular apparatus may contribute to its action. Here, it is given in the form of the hydrobromide (scopolamine), 1 mg of which contains 0.7 mg of the laevo-hyoscine base. Commercially available seasickness tablets usually contain 0.3 mg and one or two are recommended for protection for short journeys. Side effects preclude the long-term use of hyoscine for travel sickness. 

The GP also prescribed hyoscine butylbromide 10 mg tablets, two of which were to be taken up to four times daily. 

NITRATES 1. ANALGESICS-nefopam 2. ANTIARRHYTHMICS -disopyramide, propafenone 3. ANTIDEPRESSANTS-TCAs 4. ANTI EMETICS-cydizine 5. ANTIHISTAMINES -chlorphenamine, cyproheptadine, hydroxyzine 6. ANTIMUSCARINICS -atropine, benzatropine, cydopentolate, dicydover-ine, flavoxate, homat-ropine, hyoscine, orphenadrine, oxybutynin, procyclidine, propantheline, tolterodine, trihexyphenidyl, tropicamide. 7. ANTI-PARKINSON S DRUGS-dopaminergics 8. ANTI-PSYCHOTICS - pheno-thiazines, clozapine, pimozide 9. MUSCLE RELAXANTS-baclofen 1. t risk of antimuscarinic side-effects when isosorbide dinitrate is co-administered with these drugs 2. 1 efficacy of sublingual nitrate tablets... 

Hyoscine has antimuscarinic side-effects that may add to the effect of a wide range of prescribable medications such as TCAs. Also, the antimuscarinic effect may reduce the efficacy of sublingual GTN tablets. 

Scopolamine (hyoscine N-butylbromide) is available as an antispasmodic product (20 mg ampule for injection and 20 mg tablets) for use in humans. In addition, there is a veterinary product that contains scopolamine and dipyrone approved for use as an antispasmodic/analgesic in animals. In addition to blocking the effects of acetylcholine at the muscarinic receptor, scopolamine affects nicotinic receptors in intestinal ganglia and does not affect the CNS. In horses, scopolamine is used as an antispasmodic and to relax the rectum to facilitate abdominal palpation. In one report, 0.2 mg/kg was as effective as 0.2 mg/kg scopolamine plus 2.5 mg/kg dipyrone in relieving discomfort caused by balloon dilatation of the cecum (Roelvink et al 1991). The analgesic effect tasted for 20 min. 

These are medicines that are listed in the Prescription Only Medicines (ffuman Use) Order 1997. If the pack size of a POM is reduced it may be considered for licensing as a P or GSL medicine (see paracetamol example in Section 1.3.1). If a POM is intended for sale below a certain strength or dose then the medicine may be also considered to be a P medicine. An example of this is hyoscine butylbromide tablets 10 mg, which are normally classified as a POM but if packaged and labelled appropriately, a P classification is given. For P classification in this example, the packaging must state that a single dose must not exceed 20 mg and the daily dose must not exceed 80 mg and the pack must contain no more than 240 mg. 

Tablets of Hyoscine Hydrobromide, B,P, Usually contain 1/200 grain.

---