Histamine is a biogenic amine present in many tissues that functions as a neurotransmitter and is involved in inflammatory and hypersensitivity reactions. It is synthesized from the amino acid histidine. Histamine acts through multiple receptor subtypes and is involved in various physiological processes like gastric acid secretion, smooth muscle contraction, and allergic responses. Antihistamines competitively inhibit histamine receptors, with first generation antihistamines having sedative effects and second generation ones having minimal side effects. They are used to treat allergic disorders, as antiemetics, and for gastric acid reduction with H2 blockers. Concerns have been raised about impurities in the H2 blocker ranitidine. While H3
5-Hydroxytryptamine & it’s Antagonist is a Topic in Pharmacology which will defiantly Help You in pharmacy field All information is related to pharmacology drug acting and it's effect on body. it is collage project given by our department i would like to share with you.
Autacoids - pharmacological actions and drugs related to them. SIVASWAROOP YARASI
Autacoids or "autocoids" are biological factors which act like local hormones, have a brief duration, and act near the site of synthesis. The word autacoids comes from the Greek "autos" (self) and "acos" (relief, i.e. drug).
5-Hydroxytryptamine & it’s Antagonist is a Topic in Pharmacology which will defiantly Help You in pharmacy field All information is related to pharmacology drug acting and it's effect on body. it is collage project given by our department i would like to share with you.
Autacoids - pharmacological actions and drugs related to them. SIVASWAROOP YARASI
Autacoids or "autocoids" are biological factors which act like local hormones, have a brief duration, and act near the site of synthesis. The word autacoids comes from the Greek "autos" (self) and "acos" (relief, i.e. drug).
this presentation gives the knowledge about the decongestants are a type of medication that can provide short relief for a blocked nose ................
this will give brief about the peptic ulcer and give information about the drug used for peptic ulcer and classification of drugs including drugs and there use adverse effect.
Seretonin (5HT) and Its Antagonists PharmacologyPranatiChavan
Serotonin is a chemical that has a wide variety of functions in the human body. It is sometimes called the happy chemical, because it contributes to wellbeing and happiness.
The scientific name for serotonin is 5-hydroxytryptamine, or 5-HT. It is mainly found in the brain, bowels, and blood platelets.
Serotonin is used to transmit messages between nerve cells, it is thought to be active in constricting smooth muscles, and it contributes to wellbeing and happiness, among other things. As the precursor for melatonin, it helps regulate the body’s sleep-wake cycles and the internal clock.
It is thought to play a role in appetite, the emotions, and motor, cognitive, and autonomic functions. However, it is not known exactly if serotonin affects these directly, or if it has an overall role in co-ordinating the nervous system.
this presentation gives the knowledge about the decongestants are a type of medication that can provide short relief for a blocked nose ................
this will give brief about the peptic ulcer and give information about the drug used for peptic ulcer and classification of drugs including drugs and there use adverse effect.
Seretonin (5HT) and Its Antagonists PharmacologyPranatiChavan
Serotonin is a chemical that has a wide variety of functions in the human body. It is sometimes called the happy chemical, because it contributes to wellbeing and happiness.
The scientific name for serotonin is 5-hydroxytryptamine, or 5-HT. It is mainly found in the brain, bowels, and blood platelets.
Serotonin is used to transmit messages between nerve cells, it is thought to be active in constricting smooth muscles, and it contributes to wellbeing and happiness, among other things. As the precursor for melatonin, it helps regulate the body’s sleep-wake cycles and the internal clock.
It is thought to play a role in appetite, the emotions, and motor, cognitive, and autonomic functions. However, it is not known exactly if serotonin affects these directly, or if it has an overall role in co-ordinating the nervous system.
Outline:
What is the antihistamines.
What is histamine.
What is the receptors.
What is the clinical uses of antihistamines.
Side effects of antihistamines.
What is the contraindications.
Genetic polymorphisms are variations in gene sequences that occur in at least 1% of the general population, resulting in multiple alleles or variants of a gene sequence.
The most commonly occurring form of genetic variability is the single nucleotide polymorphism (SNP, often called “snip”)
Population pharmacokinetics is the study of the sources and correlates of variability in drug concentrations among individuals who are the target patient population receiving clinically relevant doses of a drug of interest
Clinical pharmacokinetics is the discipline that applies pharmacokinetic concepts and principles in humans in order to design individualized dosage regimens which optimize the therapeutic response of a medication while minimizing the chance of an adverse drug reaction.
Cardiac cycle is defined as the succession of coordinated events taking place in the heart during each beat. Each heart beat consists of two major periods called systole and diastole.
Although some lymphocytes have a lifetime measured in years, most formed elements of the blood last only hours, days, or weeks, and must be replaced continually.
Negative feedback systems regulate the total number of RBCs and platelets in circulation, and their numbers normally remain steady.
The abundance of the different types of WBCs, however, varies in response to challenges by invading pathogens and other foreign antigens.
The heart has four chambers. The two superior receiving chambers are the atria (= entry halls or chambers), and the two inferior pumping chambers are the ventricles (= little bellies).
On the anterior surface of each atrium is a wrinkled pouchlike structure called an auricle
Desmopressin
Lypressin
Terlipressin
Felypressin
Argipressin
ornipressin
Desmopressin: It is a selective V2-receptor agonist and is more potent than vasopressin as an antidiuretic. It has negligible vasoconstrictor action. It is administered by oral, nasal and parenteral routes. Lypressin: It acts on both V1- and V2-receptors. It is less potent but longer acting than vasopressin. It is administered parenterally. Terlipressin: It is a prodrug of vasopressin with selective V1 action. It is administered intravenously. Felypressin: It is a synthetic analogue of vasopressin. It is mainly used for its vasoconstrictor (V1 ) action along with local anaesthetics to prolong the duration of action. Felypressin should be avoided in pregnancy because of its oxytocic (uterine stimulant) activity.
Management of Peripheral Neuropathy and Cardiovascular Effects in Vitamin B1...PARUL UNIVERSITY
Peripheral nerves are susceptible to damage by a wide array of toxins, medications, and vitamin
deficiencies. Vitamin B12 (VB12) deficiency neuropathy is a rare debilitating disease that affects
mostly the elderly. It is important to consider these etiologies when approaching patients with a variety
of neuropathic presentations in this review were have included most relevant and latest information on
mechanisms causing Peripheral neuropathy in VB12 deficiency. We also have included cardiovascular
disorders and their management. Hyperhomocysteinemia has been implicated in endothelial
dysfunction and cardiovascular disease. The association of homocysteine (Hcy) and VB12 with
cardiovascular risk factors in patients with coronary artery disease (CAD) has also been studied
Moyamoya disease (MMD) is a rare and unique cerebrovascular disease. The term “moyamoya” is Japanese and refers to a hazy puff of smoke or cloud. In people with moyamoya disease, this is how the blood vessels appear in the angiogram. MMD is characterized by the progressive stenosis of the distal internal carotid artery (ICA) resulting in a hazy network of basal collaterals called moyamoya vessels. This may be a consequence of Mutations in a few genes. In addition, MMD is also associated with many genetically transmitted disorders, including neurofibromatosis, Down syndrome, Sickle cell anemia, and Collagen vascular disease. It follows bimodal age distribution. Younger populations present with ischaemic symptoms, whereas adults show hemorrhagic symptoms The exact cause remains unknown. Immune, genetic and other factors contribute to this disease. It follows complex pathophysiology resulting in neovascularization as a compensatory mechanism. Diagnosis is based on cerebral angiography using the DSA scale. Treatment involves managing symptoms with medicine or surgery, improving blood flow to the brain, and controlling seizures. Revascularization helps to rebuild the blood supply to the underside of the brain.
A case report on Rheumatoid Arthritis with sickle cell traitPARUL UNIVERSITY
A female patient aged 6 years, a suspected case of sickle cell trait (SCT) having symptoms of Rheumatoid arthritis (RA),
while evaluating joint complaints in adult sickle cell disease (SCD) patients, a number of sickle cell-based entities come
to mind such as avascular necrosis, osteomyelitis, bone infarcts, and septic arthritis. RA is a chronic systemic
inflammatory disease, many reports highlighted the occurrence of RA in SCD presenting as diagnostic challenges for
cases with chronic inflammatory arthritis, SCT also have appeared to persist in some populations at a perplexingly high
rate given the degree of early mortality of homozygosity of SCD, our case report showed that not only SCD but if a patient
has SCT they can develop RA as complication. Our case report concludes that during the evaluation of a SCT patient who
presents with chronic synovitis, one should strongly consider the possibility of coexistence of RA and SCT.
The appendicular skeleton consists of the
shoulder girdle with the upper limbs and the
pelvic girdle with the lower limbs
Shoulder girdle and upper limb:
Each shoulder girdle consists of:
•1 clavicle
•1 scapula.
Each upper limb consists of the following bones:
1 humerus, 1 radius, 1 ulna, 8 carpal bones, 5 metacarpal bones and 14 phalanges.
Anabolic steroids promote protein synthesis and increase muscle mass, resulting in weight gain.
Testosterone is secreted by the testis and is the main androgen in the plasma of men. In women, testosterone (in small amounts) is secreted by the ovary and adrenal glands. Many of the androgens are modified forms of testosterone
Kinetics: Absorbed orally and from of injection site and undergoes rapid first pass metabolism and quick metabolism respectively. In order to retard the rate of absorption, testosterone esters in oil are used which are less polar than the free steroid.
DKA
HHS
CASE DISCUSSION
DIABETES COMPLICATION
Hyperglycaemia is the main cause leading to dehydration due to osmotic diuresis which, if severe, results in hyperosmolarity. In HHS, unlike diabetic ketoacidosis, there is no significant ketone production and therefore no severe acidosis.
Hyperosmolarity may increase blood viscosity and the risk of thromboembolism. Factors precipitating HHS are infection, myocardial infarction, poor adherence with medication regimens or medicines which cause diuresis or impair glucose tolerance, for example, glucocorticoids.
A study on the pharmacological management of mineral bone disease in chronick...PARUL UNIVERSITY
In patients with chronic kidney disease (CKD), along with progression of CKD,
abnormalities of mineral and bone metabolism develop, which result in altered serum levels of minerals
such as calcium and phosphorus, as well as abnormalities in parathyroid hormone (PTH) or vitamin D
metabolism. Chronic Kidney Disease-Mineral Bone Disease (CKD-MBD) is a serious burden because of
increased cardiovascular mortality thus making therapeutic improvements essential in CKD-MBD. The
present study was aimed at evaluation of pharmacological management of CKD-MBD.
Methods:A retrospective study including 180 patients divided into two groups of 90 each (diabetes
mellitus and non-Diabetes) was performed in the Department of Nephrology, SVIMS, Tirupati. Patients
who were on follow up for at least 3 years (2015-2017) were considered, serum parameters were measured at every six months with a total of 6 visits. First visit was taken as baseline and sixth visit as
conclusion.
Results:The disease incidence of CKD-MBD is more common in male patients i.e. 67.8%. Serum calcium
levels were significantly increased and eGFR was significantly decreased in all patients with CKD at
conclusion compared to baseline.Further, Serum calcium levels were significantly increased at conclusion
in CKD patients without DM and eGFR was significantly decreased at conclusion compared to baseline
in CKD patients with DM. The proportion of untreated patients is high for all the drugs except vitamin D
analogues in both subgroups of CKD patients.
Conclusion:Pharmacological intervention in CKD patients helps in the effective management of mineral
bone disease by maintaining serum calcium, phosphate and calcium phosphorous product status.
A Retrospective Study of Clinical and Biochemical Profile in Geriatric Patien...PARUL UNIVERSITY
The aim of the study was to evaluate the clinical and
biochemical characteristics of geriatric patients with type 2
diabetes mellitus (DM) attending tertiary care teaching hospital,
SVIMS, Tirupati. OBJECTIVES: To document clinical
features, biochemical parameters and anti-diabetic medications
received as per records. METHODOLOGY: This
retrospective study was performed in Department of
Endocrinology in SVIMS, Tirupati, over a period of 6 months.
Demograghic details, laboratory parameters and
pharmacotherapy details were collected in the pre-designed
annexure form. RESULTS: A total of 100 diabetic elderly
patients were included in the study. Out of which 57 were men,
43 were women. Most of them were under the age group of
60-64 years followed by other age groups. 28 patients were
having the diabetes duration of 11-15 years. Some of them were
having diabetic complications (such as diabetic retinopathy,
diabetic neuropathy, diabetic nephropathy). Among 100
patients, 32 patients were normal weight, 22 patients were
overweight, 28 patients were obese-I, 18 patients were obese-II.
About 85% of patients were having high lipid levels. Some
patients were on Oral Hypoglycemic Agents (OHAS), some
patients were using both Insulin & OHAS.CONCLUSION:
The present study comprised of 100 elderly type 2 diabetic
patients in which males were higher in number when compared
to females, most of the patients were in the age of group of
60-64 years. Hypertension was the most common co-morbidity
associated with DM followed by Coronary Artery Disease
(CAD). Diabetic neuropathy was the most prevalent
complication followed by Diabetic retinopathy and diabetic
nephropathy. In this study 46% of the patients were obese. Most
of the patients were on OHAS alone, some were on OHAS and
Insulin combination therapy while very few were on insulin
therapy alone. Dyslipidemia was present in 85% of the patients
and the most common form of dyslipidemia was low HDL and
high LD
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
NVBDCP.pptx Nation vector borne disease control programSapna Thakur
NVBDCP was launched in 2003-2004 . Vector-Borne Disease: Disease that results from an infection transmitted to humans and other animals by blood-feeding arthropods, such as mosquitoes, ticks, and fleas. Examples of vector-borne diseases include Dengue fever, West Nile Virus, Lyme disease, and malaria.
HOT NEW PRODUCT! BIG SALES FAST SHIPPING NOW FROM CHINA!! EU KU DB BK substit...GL Anaacs
Contact us if you are interested:
Email / Skype : kefaya1771@gmail.com
Threema: PXHY5PDH
New BATCH Ku !!! MUCH IN DEMAND FAST SALE EVERY BATCH HAPPY GOOD EFFECT BIG BATCH !
Contact me on Threema or skype to start big business!!
Hot-sale products:
NEW HOT EUTYLONE WHITE CRYSTAL!!
5cl-adba precursor (semi finished )
5cl-adba raw materials
ADBB precursor (semi finished )
ADBB raw materials
APVP powder
5fadb/4f-adb
Jwh018 / Jwh210
Eutylone crystal
Protonitazene (hydrochloride) CAS: 119276-01-6
Flubrotizolam CAS: 57801-95-3
Metonitazene CAS: 14680-51-4
Payment terms: Western Union,MoneyGram,Bitcoin or USDT.
Deliver Time: Usually 7-15days
Shipping method: FedEx, TNT, DHL,UPS etc.Our deliveries are 100% safe, fast, reliable and discreet.
Samples will be sent for your evaluation!If you are interested in, please contact me, let's talk details.
We specializes in exporting high quality Research chemical, medical intermediate, Pharmaceutical chemicals and so on. Products are exported to USA, Canada, France, Korea, Japan,Russia, Southeast Asia and other countries.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
2. HISTAMINES AND ANTIHISTAMINES PHARMACOLOGY
● Histamine is a biogenic amine present in many animal and plant tissues
that function as neurotransmitters and are also found in non-neural
tissues, have complex physiologic and pathologic effects through
multiple receptor subtypes, and are often released locally.
● It is also present in venoms and stinging secretions. It is synthesized by
decarboxylation of the amino acid, histidine. Histamine is mainly present in
storage granules of mast cells in tissues like skin, lungs, liver, gastric mucosa,
placenta, etc. It is one of the mediators involved in inflammatory and
hypersensitivity reactions.
3. HISTAMINE
● Histamine occurs in plants as well as in animal tissues and is a
component of some venoms and stinging secretions.
● Histamine is formed by decarboxylation of the amino acid l-
histidine, a reaction catalyzed in mammalian tissues by the enzyme
histidine decarboxylase. Once formed, histamine is either stored or
rapidly inactivated. Very little histamine is excreted unchanged
4.
5.
6. ACTIONS OF HISTAMINES
1. Nervous system: Histamine is a powerful stimulant of sensory nerve
endings, especially those mediating pain and itching the urticarial
response and reactions to insect and nettle stings.
2. Cardiovascular system: in humans, injection or infusion of histamine
causes a decrease in BP and an increase in heart rate, vasodilation.
3. Bronchiolar smooth muscle: Causes bronchoconstriction mediated by
H1 receptors. patients with asthma are very sensitive to histamine.
4. GIT: smooth muscle contraction, acid secretion, and diarrhoea.
5. Pregnancy: pregnant women suffering anaphylactic reactions may abort
as a result of histamine-induced contractions.
6. Secretory tissue: a powerful stimulant of gastric acid secretion by
activation of H2 receptors on gastric parietal cells.
7. The “triple response”: Intradermal injection of histamine causes a
characteristic red spot, edema, and flare response.
7. ANTIHISTAMINES
● H1-receptor antagonists (classical antihistamines) lessen
histamine-mediated symptoms of allergic reaction.
Mainly used for allergic reactions.
● H2-receptor antagonists reduce gastric acidity.
Clinically has benefits in peptic ulcers and hyper acid secretion.
● H3 and H4-receptor antagonists have no therapeutic indication.
8.
9. CLASSIFICATION DEPENDING ON
SEDATION
● Highly sedating— diphenhydramine, dimenhydrinate,doxylamine,
embramine, promethazine and hydroxyzine.
● Moderately sedating— pheniramine, antazoline, trimeprazine,
meclizine and buclizine.
● Mildly sedating— chlorpheniramine, methdilazine, mepyramine,
dimethindene, triprolidine, mebhydroline, cyclizine and clemastine.
● Non-sedating— terfenadine, astemizole, cetirizine and loratidine.
● Anti-vertiginous— cinnarizine.
10.
11.
12. FIRST-GEN. H1-BLOCKERS
● (CNS) depression —sedation and drowsiness. some antihistamines have
antiemetic and antiparkinsonian effects.
● They have antiallergic action, hence most of the manifestations of Type-I
reactions are suppressed.
● They have anticholinergic actions —dryness of mouth, blurring of vision,
constipation, urinary retention, etc.
H1-antihistamines are well absorbed after oral and parenteral administration.
They are distributed widely throughout the body, metabolized extensively in
liver and excreted in urine.
● Adverse effects
● sedation, drowsiness, lack of concentration, headache, fatigue, weakness,
lassitude, incoordination, etc.
● Anticholinergic side effects such as dryness of mouth, blurring of vision,
constipation and urinary retention..
● Allergic reactions may occur rarely with these agents, especially contact
dermatitis on topical application.
13. SECOND-GEN. H1-BLOCKERS
● Cetirizine, loratadine, azelastine and fexofenadine are highly
selective for H1-receptors and have the following properties.
They: Have no anticholinergic effects,
Lack antiemetic effect.
Do not cross blood–brain barrier (BBB), hence cause minimal/no
drowsiness.,
Do not impair psychomotor performance.
Are relatively expensive.
14.
15. DRUG INTERACTIONS
● Lethal ventricular arrhythmias occurred with terfenadine or
astemizole, in combination with ketoconazole, itraconazole, or
macrolide antibiotics such as erythromycin. These antimicrobial drugs
inhibit the metabolism of many drugs by CYP3A4 and cause significant
increases in blood concentrations of the antihistamines.
● Grapefruit juice also inhibits CYP3A4 and has been shown to increase
blood levels of terfenadine significantly.
● Both terfenadine and astemizole were withdrawn from the US market in
recognition of these problems. Where still available, terfenadine and
astemizole should be considered to be contraindicated in patients taking
ketoconazole, itraconazole, or macrolides and in patients with liver
disease.
16. USES OF ANTIHISTAMINES(H1)
● Uses: various allergic disorders—rhinitis, dermatitis, conjunctivitis,
urticaria, eczema, drug and food allergies.
● Preanaesthetic medication: Promethazine is used for its sedative
and anticholinergic effects.
● As antiemetic: Promethazine, diphenhydramine, dimenhydrinate,
etc. are useful for prophylaxis of motion sickness, Parkinsonism,
controlling vertigo in Meniere’s disease, blood transfusion and
saline infusion reactions
● Sedative and hypnotic: H1-antihistamines (e.g. promethazine and
diphenhydramine) are used to induce sleep, especially in children
during minor surgical procedures.
17. H-2 BLOCKERS
● Histamine-2 receptor antagonists competitively inhibit the interaction
of histamine with H2 receptors. They are highly selective and have
little or minimal effect on H1 or other receptors. H2 antagonists
mainly interfere with gastric secretion.
● Important examples of this group of drugs used widely in the
treatment of peptic and duodenal ulcer, include
● cimetidine,
● ranitidine,
● famotidine,
● nizatidine and
● roxatidine.
18.
19. IMP
. POINTS OF H2 BLOCKERS
Cimetidine is the enzyme inhbitor and increases amitryptiline, benzodiazepines,
carbamazepine, imipramine, lignocaine, nifedipine, phenytoin, quinidine, terfenadine,
theophylline, verapamil and warfarin levels, Gynaecomastia, Teratogenecity and increased
prolactin levels may be seen following therapeutic doses of cimetidine.
H2 blockers can produce bradycardia, hypotension, AV block and sinus arrest (especially
with rapid IV administration),
haematologic (agranulocytosis, pancytopenia, aplastic anaemia, and thrombocytopenia)
and dermatologic (including Stevens-Johnson syndrome, toxic epidermal necrolysis).
Cimetidine, ranitidine, and famotidine have been associated with drug-induced fever,
which typically resolves within 48 to 72 hours after discontinuation of the drug and The most
consistent adverse reaction reported with famotidine is a severe, throbbing headache.
H2 antagonists compete with creatinine and certain drugs (eg, procainamide) for renal
tubular secretion
20. CONTROVERSIES OF ZANTAC
The U.S. Food and Drug Administration announced it is requesting
manufacturers withdraw all prescription and over-the-counter (OTC)
ranitidine drugs from the market immediately. This is the latest step in an
ongoing investigation of a contaminant known as N-
Nitrosodimethylamine (NDMA) in ranitidine medications (commonly
known by the brand name Zantac).
21. H3 AND H4 BLOCKERS
● Although no selective H3 or H4 ligands are presently available for
general clinical use, there is great interest in their therapeutic potential.
● H3-selective ligands may be of value in sleep disorders, narcolepsy,
obesity, and cognitive and psychiatric disorders. Tiprolisant, H3-
blocker, has been shown to reduce sleep cycles in mutant mice and in
humans with narcolepsy.
● No selective H4 ligand is available for use in humans, Several studies
have suggested that H4-receptor antagonists may be useful in pruritus,
asthma, allergic rhinitis, and pain conditions.