General information Pentamidine, an aromatic diamine, has been known since the late 1930s as a treatment for trypanosomiasis and some forms of leishmaniasis. In recent times it has been extensively used in the treatment of Pneumocystis jirovecii pneumonia. Its mechanism of action is probably related to inhibition of dihydrofolate reductase and inhibition of oxidative phosphorylation and nucleic acid synthesis, as well as an effect on aerobic…

General information Pentagastrin is a short peptide that stimulates the production of gastric acid from the stomach by a direct action on gastrin receptors and of calcitonin from thyroid C cells [ ]. It also acts on cholecystokinin receptors centrally and stimulates the release of adrenocorticotropin (ACTH) and hence the production of glucocorticoids [ ]. Pentagastrin was originally used to test for suppression of gastric acid…

See also Beta-lactam antibiotics General information The basic structure of the penicillins consists of a thiazolidine ring, the beta-lactam ring, and a side chain. The beta-lactam ring is essential for antibacterial activity. The side chain determines in large part the antibacterial spectrum and pharmacological properties of a particular penicillin. The rapid emergence of bacteria, particularly Staphylococcus aureus , that produce beta-lactamases (penicillinase) has been partly countered…

General information Penicillamine is dimethylcysteine or 2-amino-3-mercapto-3-methylbutyric acid, a sulfur-containing amino acid. It has three functional groups that largely determine its pharmacological effects: an alpha-amine, a carboxyl, and a sulfhydryl group. Because the levorotatory isomer, l -penicillamine, is a pyridoxine antagonist and toxic, purified d -penicillamine is used for medicinal purposes instead of the racemic mixture. Here “penicillamine” refers to the d -isomer unless otherwise specified.…

General information Pemoline has similar pharmacological actions to dexamfetamine and methylphenidate, and was used in the management of hyperactivity disorders in children. However, the evidence linking pemoline to life-threatening liver failure prompted the Food and Drugs Administration to require the manufacturer to add a black box warning to the package insert, and in the UK the Committee on Safety of Medicines withdrew marketing approval for pemoline,…

General information Pemirolast is a mast-cell stabilizer, like cromoglicate, used in eye-drops for the treatment of allergic disorders [ ]. It has also been used to prevent coronary artery restenosis after the insertion of a stent [ ]. Drug studies 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

General information Pemetrexed (LY231514, MTA) is an antifolate congener. It is transported into cells by the reduced folate carrier and undergoes intracellular polyglutamylation, resulting in a persistent cytotoxic metabolite, which targeting several enzymes simultaneously, including dihydrofolate reductase, thymidylate synthase, GARFT, and AICARFT [ ]. Pemetrexed was approved as monotherapy for the treatment of advanced non-small cell lung cancer and in combination with cisplatin for the treatment…

General information Pegvisomant is a genetically engineered growth hormone analogue that acts as a growth hormone receptor antagonist and is used to treat acromegaly. Drug studies Observational studies In 229 patients with a 9 year history of acromegaly who were treated with pegvisomant in a mean dose of 16.5 mg/day for a median duration of 1 year, adverse events included injection site reactions, including erythema, swelling,…

General information Pegaptanib is a pegylated anti-VEGF aptamer, which is used to treat wet age-related macular degeneration and diabetic macular edema [ ]. Drug studies Observational studies Adverse reactions to intravitreal injection of pegaptanib (0.3, 1, or 3 mg every 6 weeks) over 2 years have been reported in 1190 patients who took part in two concurrent, prospective, randomized, multicenter, double-masked, sham-controlled studies [ ]. The…

See also Fluoroquinolones General information Pefloxacin is a fluoroquinolone antibiotic that inhibits Plasmodium falciparum in vitro. It is effective against Plasmodium yoelii infections in mice. General adverse effects and adverse reactions The adverse effects of pefloxacin and reactions to it are those of the fluoroquinolones. Gastrointestinal complaints occur in some 3–6% and have included (in declining order of frequency) nausea, abdominal discomfort, vomiting, and diarrhea. Colitis…

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See also Fluoroquinolones General information Pazufloxacin is an injectable quinolone antibiotic with bactericidal effect against cephalosporin-resistant, carbapenem-resistant, and aminoglycoside-resistant strains of bacteria. 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 Imatinib General information Pazopanib is a potent, selective, broad-spectrum, multi-targeted inhibitor of receptor tyrosine kinases, including VEGFR-1, VEGFR-2, VEGFR-3, PDGFR-α/β, and c-kit. Total disease control in patients with advanced renal cell carcinoma was 82%. The most common adverse events included rises in aminotransferase activities, diarrhea, fatigue, nausea, hair depigmentation, and hypertension. According to an interim analysis, adverse reactions led to drug withdrawal in 5%…

General information The family of Passifloraceae contains the single genus Passiflora incarnata , which contains over 500 species. 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

General information Human parvovirus B19 is the causative agent of fifth disease, a rash-like disease of childhood, and in adults can cause arthralgia and chronic arthritis [ , ] and pure red cell aplasia [ ]. However, it has more serious consequences in pregnant women, in whom it can cause hydrops fetalis or abortion, and in patients with chronic or acquired immunodeficiency, in whom it can…

See also Selective serotonin re-uptake inhibitors (SSRIs) General information Paroxetine is a phenylpiperidine derivative and a selective serotonin reuptake inhibitor (SSRI). Pharmacokinetics The half-life of paroxetine is about 17–22 hours and about 95% of it is bound to plasma proteins. Its metabolites have no more than 1/50 of the potency of the parent compound in inhibiting serotonin re-uptake. The metabolism of paroxetine is accomplished in part…

General information Parenteral nutrition should be tailored to the needs of the individual, but on average should provide about 25 kcal Solutions for long-term parenteral nutrition should contain: about 30% carbohydrate, usually in the form of glucose, providing 60% of the energy requirements; 30–50% fat in the form of a lipid emulsion such as soya oil; amino acids, 150–250 kcal/g of nitrogen; sodium and potassium; calcium,…

See also COX-2 inhibitors (coxibs) General information Parecoxib sodium is an injectable COX-2 inhibitor developed for the treatment of acute pain. It is a prodrug of a sulfonamide-based COX-2 inhibitor, valdecoxib, a potent anti-inflammatory and analgesic drug. The published information on this compound is inadequate to draw any conclusion about its tolerability. Single-dose and multiple-dose studies have not shown any safety problems compared with placebo […

General information Both intact parathyroid hormone (e.g. PTH 1–34 , teriparatide) and smaller N-terminal fragments PTH 1–84 are used therapeutically. Recombinant PTH 1–34 is called teriparatide. No adverse reactions have been reported with single infusions of up to 60 mg of synthetic human parathyroid hormone in diagnostic procedures [ , ]. Although bone resorption increases if the hormone is given continuously or in high doses, it…

General information Paraldehyde is the cyclic trimer of acetaldehyde, a colorless or slightly yellow-colored liquid. It has been used as an anticonvulsant, but because of adverse reactions and because it is difficult to use it has been replaced by more modern agents. However, it is still sometimes used to treat status epilepticus that is resistant to first-line drugs [ ]. The usual adult rectal dose is…