Pka 83 its an acid with a pka well above 7 some books

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pKa 8.3 It’s an acid with a pKa well above 7. (Some books give an even higher pKa.) Mean Vd 0.7 L/kg Plasma Protein Binding 70-95%.
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Oral Bioavailability Up to 98% (low extraction drug, no “first pass” effect). Poor i.m. bioavailability. Half-Life 24 hours (but “concentration dependent”, which means that after metabolism shifts to “pseudo zero order” the “half-life” may become much longer) Note: a long half-life is typical of a low extraction drug that is highly protein bound. Absorption Slow and variable (peak after 2-6 hours after p.o administration. (Perhaps because it has poor water solubility.) Distribution To all tissues (total body water). Elimination Almost all hepatic (2% excreted unchanged). Goes through phases 1 and 2. Can be excreted as parahydroxyphenyl phenytoin (phase 1) or as glucoronidated form (phase 2). Can saturate the liver and go to “pseudo zero order” elimination at or near therapeutic concentrations.) Also excreted in bile. ADR’s The major ADR’s are sedation, stomach upsets, gingival hyperplasia (over growth of gum tissue), hirsutism (growth of body hair), In overdose (toxic syndrome) causes nystagmus (jumpy eye movements), ataxia (clumsiness) and psychosis (rare). There is a rare, life- threatening hypersensitivity syndrome, with autoimmune attack of the liver, kidney, bone marrow, skin (Stevens-Johnson syndrome). Interactions Disulfiram and isoniazid can raise phenytoin blood levels in low acetylators . Propranolol (non-proprietarpy name) Galenical Source None Brand Names Apo-Propranlol, Dentensol, Inderal , Inderal-LA. (Inderal was the original brand name.) Inderal-LA is a “slow release” formulation. Drug Class Beta-adrenoceptor blocker. Usually called a “beta blocker”. Blocks noradrenaline beta 1 (desirable) and beta 2 (undesirable) receptors. Related Drugs metoprolol, timolol, acebutalol, pindolol. Note: They all end in “olol”. Mechanism of Action Blockade of beta noradrenergic receptors. (Recently developed “related drugs” block only beta-1 receptors.) pKa 9.45
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Mean Vd 3 L/kg Plasma Protein Binding 93% (to alpha-1 acid glycoprotein) Oral Bioavailability 25-50% (High extraction drug with a large first pass effect. No “protection” due to binding to plasma proteins.) Absorption increases if liver is diseased (hepatitis, cirrhosis). Half-Life 3-5 hours (prolonged by liver disease) Absorption Rapid and almost complete. Peak levels at 30-90 minutes after p.o. dosing. Distribution All tissues (total body water) Elimination Completely biotransformed. Phase 1 (oxidation) and Phase 2 (glucuronidation) are main routes. Followed by excretion of metabolites. ADR’s Many types. Acute G.i .: nausea, vomiting, diarrhea; cardiac : bradycardia (slow heart beat), cardiac failure, heart block. (“Any drug in excess becomes a poison.”); respiratory : brancho- constriction Chronic hallucinations, sleep disorders, depression, cold extremities Interactions May prolong the hypoglycemia caused by insulin.
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