Drugs affecting the gastrointestinal system & nutrition

Drugs affecting the gastrointestinal system & nutrition

AntidiarrhealMechanism of action and drug effectsIndicationsContraindicationsadverse effectsInteractionsdosages

Mechanism of action and drug effectsIn contrast, adsorption refers to penetration into substance for interior structure (e.g. absorption of dietary nutrients into intestinal villi)Adsorbent, the uptake of substances across a surfaceIndicationscontraindicationsAntidiarrheal drugs indicated for treatment of diarrhea from various types and levels od severity.Adsorbents most likely to be used in milder cases.Anticholinergics and opiates tend to be used in severe cases.Intestinal flora modifiers helpful in patients with antibiotic-induced diarrhea.Drug allergyMajor acute GI condition; intestinal obstruction or colitis (unless prescribed by patients physicians after careful considerations of specific cases.Adverse effects of antidiarrhealDrugsBody SystemAdverse EffectsAdsorbents(bismuth subsalicylate)HematologicIncreased bleedingGastrointestinalConstipation, dark stoolsCNSConfusion, twitchingOtherHearing loss, tinnitus, metallic taste, blue gumsAnticholinergics(atropine, hyoscyamine, hyoscine)GenitourinaryUrinary retention and hesitancy, impotenceCNSHeadache, dizziness, confusion, anxiety, drowsinessCardiovascularHypotension, hypertension, bradycardia, tachycardiaIntegumentaryDry skin, rash, flushingEye, ear, nose, throatBlurred vision, photophobia, increased pressure in the eyeAdverse effects of antidiarrhealDrugsBody SystemAdverse EffectsOpiates(codeine)CNSDrowsiness, sedation, dizziness, lethargyGastrointestinalNausea, vomiting, anorexia, constipationRespiratoryRespiratory depressionCardiovascularBradycardia, palpitations, hypotensionGenitourinaryUrinary retentionIntegumentaryRash, flushing, urticariaDrug profilesAge 3-5 years old= 5mLAge 6-9 years old= 10mLAge 10-12 years old= 15mLDosagesHalf-life= 24-33 hr.Onset= 0.5-2 hr.Peak= 2-5 hr.Duration= variable*for uncomplicated diarrheaPharmacokineticsCaution for children and teenagers due to the risk of Reyes syndromeImmediate report if abdominal distension, firm abdomen, painful abdomen, worsening or no improvement of diarrhea 24 to 48 hours after medication administered.

Life span considerationsTwo alarming but harmless adverse effects are temporary darkening of tongue and/or stool.Adverse effectAdsorbentsBismuth subsalicylate*available OTC for oral useDrug profilesAdult= 5-10mL 2 caps or tabsDosagesHalf-life= unknownOnset= 1-2 hr.Peak= 2-3 hr.Duration= 6-8 hr.*for anticholinergic effectsPharmacokineticsToward pt. who have shown a hypersensitivity to anticholinergics.Pt. with glaucoma, GI obstruction, myasthenia gravis, paralytic ileus and toxic megacolon.ContraindicationsFour different alkaloids; atropine, hyoscymine, phenobarbital & scopolamine = donnatalCombinations ofAnticholinergicsAtropine, hyoscyamine, hyoscine a.k.a belladonna alkaloids*only by prescriptionDrug profilesPediatric 2-5 yr. = 1 mg (liquid only)Pediatric 6-8 yr. = 2 mgPediatric 9-12 yr. = 2 mgAdult= 4 mg followed by 2mg after each BM (not exceed 16mg/day)*BM- bowel movementDosagesHalf-life= 2.5-4 hr.Onset= 40-60 min.Peak= 2-3 hr.Duration= 3-4 hr.*Diphenoxylate componentPharmacokinetics*Synthetic opiates agonistActs on smooth muscle of the intestinal tract, inhibiting GI motility and excessive GI propulsion.Little or no analgesic activity.If taken in large dosages, result in extreme anticholinergic effects (e.g. dry mouth, abdominal pain, tachycardia, blurred vision)Diphenoxylate withatropineInhibits both peristalsis in the intestinal wall and intestinal secretion, thereby decrease the number of stools and its water contentContraindicated toward pt. with severe ulcerative colitis, pseudomembranous colitis and acute diarrhea d/t Escherichia coliLoperamideOpiatesCodeine, diphenoxylate with atropine, paregoric, tincture of opium (prescription only)Loperamide (OTC)Drug profilesLaxativesMechanism of action and drug effectsIndicationsContraindicationsadverse effectsInteractionsdosages

Mechanism of action and drugs effectTreatment for constipation; abnormally infrequent and difficult passage of feces through the lower GI tract.Common causes of constipation are noted in Table 7.3Laxatives act asAffecting fecal consistencyIncreasing fecal movement through the colonFacilitating defecation through the rectum

IndicationscontraindicationsDrug allergy; caution if presence the following of,Appendicitis symptoms (such as abdominal pain, nausea, and vomiting)Fecal impactionIntestinal obstructionUndiagnosed abdominal painAdverse effectCategoriesAdverse EffectsBulk forming laxativesImpaction above stricturesFluid disturbancesGas formationEsophageal blockageAllergic reactionEmollientSkin rashesDecreased absorption of vitaminsLipid pneumoniaHyperosmoticAbdominal bloatingRectal irritationSalineCrampingDiarrheaStimulantMelanosis coli (buku 2nd)Chronic administration lead to cathartic colon; a progressive deterioration of colon function that can exacerbate an existing bowel dysfunction.Drug profilesAttracts water into the intestines & absorbs excess water into the stoolStimulates intestines & increase peristalsisHalf-lifeOnsetPeakDurationUnk.12-24 hrUnk.Unk.Contraindicated with pt. having intestinal obstruction or fecal impaction, abdominal pain and/or nausea and vomitingDrug profilesLubricate the stool & the intestines, as with mineral oilORFecal softener

Half-lifeOnsetPeakDurationUnk.1-3 daysUnk.1-3 daysContraindicated with pt. having intestinal obstruction or fecal impaction, abdominal pain and/or nausea and vomitingANTIEMETIC & ANTINAUSEA DRUGMechanism of action and drug effectsIndicationsContraindicationsadverse effectsInteractionsdosages

Nausea and vomitingNausea; an unpleasant feeling that precedes vomiting.Vomiting also known as emesis; the forcible emptying or expulsion of gastric and occasionally, intestinal contents through the mouthNeurotransmitterSite in the vomiting pathwayAcetylcholineVC in brain; vestibular and labyrinthine pathway in inner earDopamine D2GI tract and CTZ in brainHistamine H1VC in brain; vestibular and labyrinthine pathways in inner earProstaglandinsGI tractSerotoninGI tract; CTZ and VC brainCTZ, chemoreceptor trigger zone; VC, vomiting centerMechanism of actionAnticholinergic drug; bind to and blocking acetylcholine (ACh) receptor in vestibular nuclei, also dry the GI secretions and reduce smooth muscle spasmsAntihistamines; HI blockers, bind primarily H1 receptor. Prevent cholinergic stimulation in both vestibular and reticular systems.Neuroleptic drug; prevent nausea and vomiting by blocking dopamine receptor on CTZ. Benefits in calming the CNS.Prokinetic drugs; in particular metoclopramide, acts as antiemetics by blocking dopamine receptors in CTZ, which desensitize CTZ to impulses it receives from the GI tractSerotonin blockers; blocking serotonin receptors. Located throughout the body, CNS, smooth muscles, platelets and GI tract.Tetrahydrocannabinol (THC); inhibitory effects on reticular formation, thalamus and cerebral cortex. Cause an alteration in mood and the bodys perception of its surrounding thus relieve nausea and vomiting.MineralsCalciumMagnesium

Phosphoruszinc

Mineral TypesMechanism of ActionIndicationsContraindicationsAdverse effectsInteractionsCalciumCofactor in clotting reactions; conversion of prothrombin to thrombin by thromboplastin and fibrinogen to fibrinMaintenance and function of the nervous, muscular and skeletal systems and for cell membrane and capillary permeability.Transmission of nerve impulseContraction of cardiac, smooth and skeletal musclesRenal functionRespirationPlays a regulatory roles in release and storage of neurotransmitter and hormonesUptake and binding of amino acidsIntestinal absorption of cyanocobalamin (vitamin b12) and gastrin secretionMenopausePancreatitisPregnancy and lactationPMSVitamin D deficiencyAdult osteomalaciaMuscle crampsHypercalcemiaVentricular fibrillation of heartAllergyHypercalcemia can occurSymptom:AnorexiaNauseaVomitingconstipationCalium salts will chelate (bind) with tetracyclines to produce an insoluble complexMineral TypesMechanism of ActionIndicationsContraindicationsAdverse effectsInteractionsMagnesiumCofactor for many enzyme systems.Required for muscle contraction and nerve physiologyProduces an anticonvulsant effect by inhibiting neuromuscular transmission for selected convulsive statesMagnesium deficiencyPreeclampsia and eclampsiaInhibition of uterine contractions in premature laborCardiac arrhythmiasShort-term constipationDrug product allergyHeart blockRenal failureHypercalcemia can occurSymptom:AnorexiaNauseaVomitingconstipationCalium salts will chelate (bind) with tetracyclines to produce an insoluble complex