General information There is a range of bipyridines that are selective inhibitors of a specific isoenzyme of phosphodiesterase, F-III. These include amrinone (inamrinone), enoximone (fenoximone), milrinone, olprinone, pimobendan, sulmazole, and vesnarinone. Their clinical pharmacology has been reviewed [ ]. The pharmacology, clinical pharmacology, uses, therapeutic value and adverse effects of positive inotropic drugs other than digitalis have been reviewed [ ], as has the suggestion that…

General information Phosphatidylcholine and its derivatives form a class of phospholipids that are major components of biological membranes and pulmonary surfactant (dipalmitoyl phosphatidylcholine or lecithin). Phosphatidylcholine is an essential component of the very low-density lipoprotein (VLDL) complex that facilitates the transport of triacylglycerols out of the liver. Subcutaneous injections of phosphatidylcholine have been used for localized subcutaneous fat reduction on the face and body [ ].…

General information An oral solution of sodium phosphates (dibasic sodium phosphate + monobasic sodium phosphate) is used as a laxative for the relief of occasional constipation and is used as part of a bowel-cleansing regimen in preparing patients for surgery or colonoscopy. Sodium phosphates are considered to be potentially dangerous [ ], particularly because of their effects on electrolyte balance. The FDA has limited the container…

See also Antiepileptic drugs General information Phenytoin is the only widely used hydantoin and, unless otherwise specified, reactions discussed here refer to phenytoin. Other hydantoin derivatives include ethotoin, mephenytoin, and albutoin (all of which are obsolete), and fosphenytoin. The latter is a water-soluble prodrug that is rapidly hydrolysed to phenytoin after intravenous or intramuscular injection. It causes fewer adverse reactions near the injection site (pain, phlebitis,…

General information In the past, phenylpropanolamine was marketed extensively in over-the-counter products for a variety of indications, and dietary supplements were marketed with no premarket safety evaluation, at least by the Food and Drug Administration (FDA), since for dietary supplements that include an ingredient marketed in the USA before 15 October 1994 no FDA review is required. Because many of these products were promoted as foodstuffs,…

General information Phenylephrine is seldom given systemically but is still commonly used as a mydriatic for both diagnostic and therapeutic purposes. Ocular application of phenylephrine 10% in pledget form is used to produce hemostasis in laser-assisted in-situ keratomileusis (LASIK) surgery and other ophthalmic surgical procedures. Phenylephrine is in some countries available in a non-prescription concentration of 0.12% for use as an ocular decongestant. Phenylephrine (up to…

General information Phenylbutazone was originally a solubilizing agent for aminopyrine and was first used to treat rheumatoid arthritis and allied disorders in 1949. Phenylbutazone and its related compounds were used worldwide until the early 1980s when, following growing concern about their safety, Ciba-Geigy published its own international assessment on phenylbutazone (Butazolidine) and oxyphenbutazone (Tanderil), which summarized reports on 1182 deaths associated with them from their initial…

General information Phentolamine is a non-selective alpha-adrenoceptor antagonist. It is used to treat hypertensive crises attributable to the effects of noradrenaline, as in pheochromocytoma and during the interaction of monoamine oxidase inhibitors with amine-containing medicaments and foods [ ]. It is also used to reverse the effects of local anesthetics in which adrenaline has been used [ ] and when ischemia has occurred [ ]. It…

See also Anorectic drugs General information Despite the withdrawal of the fenfluramines, the appetite suppressants phendimetrazine and phentermine have remained in widespread use for the treatment of obesity. With phentermine, adverse reactions due to stimulation of the central nervous system are less than with dexamfetamine, although in one study withdrawal because of adverse reactions was as high as 16 of 177 patients (9%); 2 of 13…

General information Phenoxybenzamine is a non-selective irreversible alpha-adrenoceptor antagonist. It is given orally in total daily doses up to 60 mg for management of pheochromocytoma, and lower doses have been used to relieve bladder obstruction before surgery. The maximum effect may be delayed because of irregular absorption, and even after intravenous use it may not be attained for 1 hour. Some of the most severe reactions,…

See also Opioid receptor agonists General information Phenoperidine is a potent opioid analgesic often used in neuroleptanalgesia and as a respiratory depressant in ventilated patients. You’re Reading a Preview Become a Clinical Tree membership for Full access and enjoy Unlimited articles Become membership If you are a member. Log in here

See also Physical contraceptives—spermicides General information Phenol is a benzyl alcohol and a major oxidized metabolite of benzene that was introduced into medicine as an antiseptic [ ]. Although it can be prepared in an aqueous solution or in glycerine, it appears to be more effective when mixed in aqueous compounds. At a concentration of 0.2% it is bacteriostatic and at over 1% bactericidal [ ].…

See also Antiepileptic drugs ; Barbiturates ; Primidone General information Because it is cheap and of unquestioned efficacy, phenobarbital is still widely prescribed around the world, for both epilepsy [ ], including status epilepticus [ , ], and as an enzyme inducer in neonates with unconjugated hyperbilirubinemia [ , ]. However, in developed countries its use in epilepsy has fallen since the introduction of drugs that…

See also Anorectic drugs General information Phenmetrazine and phendimetrazine are central stimulants and indirect sympathomimetics related to dexamfetamine. Phendimetrazine is about 30% rapidly metabolized to phenmetrazine [ ]. Reported adverse reactions include glossitis, stomatitis, dry mouth, nausea, abdominal pain, cramps, constipation, difficulty in micturition, and headache. Because of adverse reactions and the risk of abuse it has been withdrawn in several countries. Organs and systems Cardiovascular…

See also Antihistamines General information Pheniramine is a first-generation antihistamine. Organs and systems You’re Reading a Preview Become a Clinical Tree membership for Full access and enjoy Unlimited articles Become membership If you are a member. Log in here

See also Antihistamines General information Phenindamine is an antihistamine that is reputed to cause stimulation rather than sedation in some patients. However, in one small study the central nervous system effects of phenindamine were intermediate between those of terfenadine and diphenhydramine [ ]. You’re Reading a Preview Become a Clinical Tree membership for Full access and enjoy Unlimited articles Become membership If you are a member.…

See also Monoamine oxidase inhibitors General information Phenelzine is a non-selective monoamine oxidase (MAO) inhibitor. Organs and systems Nervous system A potential risk of using a non-selective inhibitor in patients with Parkinson’s disease is illustrated by separate reports of the appearance of parkinsonism in patients taking phenelzine [ , ]. Speech blockage, so called, has been reported in a 34-year-old woman who had taken phenelzine 45…

General information Phencyclidine or 1-(1-phenylcyclohexy-1) piperidine (known as PCP, “angel dust”, and many other names) was originally developed as an anesthetic, but was abused as an illicit drug from the late 1960s onwards. It is a dopamine receptor agonist and an antagonist at the N-methyl- d -aspartate (NMDA) subtype of glutamate receptors. It has anticholinergic properties through blockade of ion channels in acetylcholine receptors. It has…

General information Phenazopyridine, an azo dye, is used as a urinary tract analgesic. Although its use is not justified, because of toxicity, and although it was, for example, withdrawn in Greece in 1984, it continues to be used [ , ], and is available over the counter in some countries, for example the USA [ , ]. Organs and systems Nervous system Aseptic meningitis was diagnosed…

General information Phenazone, commonly known as antipyrine, is still used therapeutically in some countries, although it is now used mainly as a marker of hepatic enzyme drug metabolizing activity. It is usually taken in combination with other analgesics, making attributability of adverse reactions difficult. Allergic reactions are rare [ , ]. Dichloralphenazone is a hypnotic composed of a complex of phenazone and chloral hydrate, which dissociates…