Calcium Channel Blockers(Nifedipine) Taking During Pregnancy

Calcium channel blockers (CCBs) are a highly prescribed class of drugs used for the treatment of angina pectoris, hypertension, and cardiac arrhythmias. These vasodilating agents relax smooth muscle by inhibiting the entry of calcium into muscles or by inhibiting its release from intracellular storages. This relaxation in blood vessel walls results in dilation of arteries and, subsequently, in reduction of blood pressure (Ducsay et al., 1987).

Nifedipine is a calcium channel blocker medicine that slows smooth muscle function. Muscles need calcium to function properly, and a calcium channel blocker interferes with the supply of calcium to the muscle. This allows the smooth muscle wall of the blood vessels to relax and widen, reducing blood pressure.

Nifedipine was given a pregnancy Category C rating because of potential problems in animal studies. When given to pregnant rabbits, mice, and rats, nifedipine caused increased miscarriages and birth defects. These birth defects included problems with fingers or toes, rib deformities, and cleft palate.

However, it is important to note that animals do not always respond to medicines the same way that humans do. Therefore, a pregnancy Category C medicine may be given to a pregnant woman if her healthcare provider believes that the benefits to the woman outweigh any risks to the unborn child.

Nifedipine is sometimes used to stop preterm labor, especially when other medications have failed. It helps to relax the smooth muscle of the uterus, stopping premature labor. Since nifedipine is not approved for preterm labor, however, this is considered an "off-label" use.

If you are pregnant or are thinking of becoming pregnant while taking nifedipine, let your healthcare provider know. He or she will consider both the benefits and risks of using nifedipine during pregnancy before making a recommendation in your particular situation.

Sourceshttp://health.msn.com/pregnancy/nifedipine-for-high-blood-pressure-during-pregnancy
http://www.fetal-exposure.org/resources/index.php/1996/09/01/calcium-channel-blockers-and-pregnancy/
http://blood-pressure.emedtv.com/nifedipine/nifedipine-and-pregnancy-p2.html

Read More »

Unknown Clinical Pharmacology

How Do Use Aminophylline Drugs Adverse Effects and Precautions

Indications:Treatment and prophylaxis of bronchial asthma, bronchial spasm associated with emphysema, chronic bronchitis & treatment of neonatal apnea.

Doses & Administrations:
Oral:
Adult:100-300 mg 3-4 times daily after food.
Pediatric:6mg/kg every 12 hours increased to 12 mg/kg.
For better dose range in children see theophylline.

Parenteral :Adult : Slow I/V (over 20 min ) 250 - 500 mg i.e (5 mg/kg) when necessary.
Maintenance if required, in patients notpreviously treated with xanthines
500 mcg/kg/hour slow I/V.

Pediatric :
Neonates : 0.2mg/kg/hr
6 weeks-6 months: 0.5mg/kg/hr
6 months - 1 yr : 0.6-0.7mg/kg/hr
1 to 9 years : 1-1.2 mg/kg/hour
9-12years and young adult smokers: 0.9mg/kg/hr
12 years healthy non smokers : 0.7mg/kg/hr

Adverse Effects:Nausea, vomiting, anorexia, diarrhea, rectal irritation, dizziness, headache, insomnia, convulsion,severe depression, tachycardia, circulatory failure and life threatning ventricular arrythmia.

Warnings / Precautions:Aminophylline should be used with caution in patients with severe heart, kidney, liver diseases, hyperthyroidism, congestive heart failure (CHF) or peptic ulcer. It should be used with caution in neonates and in elderly persons.

Mechanism of Action:Theophylline has two distinct actions in the airways of patients with reversible obstruction: smooth muscle relaxation (i.e., bronchodilation) and suppression of the response of the airways to stimuli (i.e., non-bronchodilator prophylactic effects). While the mechanisms of action of theophylline are not known with certainty, studies in animals suggest that bronchodilatation is mediated by the inhibition of two isozymes of phosphodiesterase (PDE III and, to a lesser extent, PDE IV) while non-bronchodilator prophylactic actions are probably mediated through one or more different molecular mechanisms, that do not involve inhibition of PDE III or antagonism of adenosine receptors. Some of the adverse effects associated with theophylline appear to be mediated by inhibition of PDE III (e.g., hypotension, tachycardia, headache, and emesis) and adenosine receptor antagonism (e.g., alterations in cerebral blood flow).

Theophylline increases the force of contraction of diaphragmatic muscles. This action appears to be due to enhancement of calcium uptake through an adenosine-mediated channel.

Sources
http://www.globalrph.com/pulmonary_theophylline.htm

Read More »

Unknown aminophylline Drugs, Clinical Pharmacology

Difference Between Sedative and Hypnotic Drugs

A sedative is a drug that produces a relaxing, calming effect. Sedatives are usually given during daytime hours,and although they may make the patient drowsy, they usually do not produce sleep. A hypnotic is a drug that induces sleep, that is, it allows the patient to fall a sleep and stay a sleep. Hypnotics also may be called soporifics. Hypnotics are given at night or hour of sleep (HS).
Sedatives and hypnotics may be divided into two classes:
barbiturates and miscellaneous sedatives and hypnotics. The barbiturates are divided into several
groups, depending on their duration of action:
• Ultrashort-acting (eg, thiamylal [Surital], thiopental [Pentothal]). The ultrashort-acting barbiturates
are used as anesthetics. Single doses have a duration of 20 minutes or less.
• Short-acting (eg, secobarbital [Seconal], pentobarbital [Nembutal]). The average duration of action
of the short-acting barbiturates is 3 to 4 hours.
• Intermediate-acting (eg, amobarbital [Amytal],aprobarbital [Alurate], butabarbital [Butisol]). The
average duration of action of the intermediate-acting barbiturates is 6 to 8 hours.
• Long-acting (eg, phenobarbital, mephobarbital[Mebaral]). The average duration of action of the
long-acting barbiturates is 10 to 16 hours

The miscellaneous sedatives and hypnotics consist of a group of nonrelated drugs and a second group called the benzodiazepines. Examples of the nonrelated group of drugs include ethchlorvynol (Placidyl), zaleplon (Sonata),and zolpidem (Ambien). The benzodiazepines are also called antianxiety drugs. Examples of the benzodiazepines include estazolam (ProSom), flurazepam (Dalmane), and quazepam (Doral).

Read More »

Unknown Anti Sedative Drug, Clinical Pharmacology

What is Narcotic Analgesics Mechanisms of Action Side Effects

Pain is a complex occurrence that is uniquely experienced by each individual. It has been defined as the emotional and sensory perceptions associated with real or Acute pain is a warning that something is not right in the body. Chronic pain is pain that persists beyond the expected time for healing. Analgesics are drugs that relieve pain. The narcotic analgesics are con-trolled substances used to treat moderate to severe pain. Nurses must be knowledgeable concerning pain assessment and management if the patient’s pain is to be adequately managed. Despite advances in technology and pharmacologic measures, evidence exists indicating that for many, pain is not managed adequately.Drugs that counteract the effects of the narcotic analgesics are the narcotic antagonists. These drugs compete with the narcotics at the receptor sites and are used to reverse the depressant effects of the narcotic analgesics.

NARCOTIC ANALGESICS

Opioid analgesics are the narcotic analgesics obtained from the opium plant. More than 20 different alkaloids are obtained from the unripe seed of the opium poppy plant. The analgesic properties of opium have been known for hundreds of years. The narcotics obtained from raw opium (also called the opiates, opioids, or opiate narcotics) include morphine, codeine, hydrochlorides of opium alkaloids, and camphorated tincture of opium. Morphine, when extracted from raw opium and treated chemically, yields the semisynthetic narcotics hydromorphone, oxymorphone, oxycodone, and heroin.Heroin is an illegal narcotic in the United States and is not used in medicine. Synthetic narcotics are those man-made analgesics with properties and actions simi-lar to the natural opioids. Examples of synthetic narcotic analgesics are methadone, levorphanol, remifen-tanil, and meperidine. Additional narcotics are listed in the Summary Drug Table: Narcotic Analgesics.

ACTIONS

Narcotic analgesics are classified as agonists, partial agonists, and mixed agonists-antagonists. The agonist binds to a receptor and causes a response. A partial agonist binds to a receptor, but the response is limited (ie, is not as great as with the agonist). Antagonists bind to a recep-tor and cause no response. An antagonist can reverse the effects of the agonist. This reversal is possible because the antagonist competes with the agonist for a receptor site.

 An agonist-antagonist has properties of both the agonist and antagonist. These drugs have some agonist activity at the receptor sites and some antagonist activity at the receptor sites.
Classification of the narcotic analgesics is based on their activity at the opioid receptor sites. Although five
categories of opioid receptors have been identified, only three of these receptors affect the action of the narcotic analgesics:
• mu
• kappa
• delta
The narcotic agonists have activity at the mu and kappa receptors (and possi-bly the delta sites). Remifentanil is a very short-acting agonist with potent analgesic activity. It is a mu opioid agonist with rapid onset, peak effect, and short duration of action. The mixed agonist-antagonist drugs act on the mu receptors by competing with other substances at the mu receptor (antagonist activity) and are agonists at other receptors. Partial agonists have limited agonist activity at the mu receptor. The actions of the narcotic analgesics on the various organs and structures of the body (also called secondary pharmacological effects) are

USES

The major use of the narcotic analgesic is to relieve or manage moderate to severe acute and chronic pain. The ability of a narcotic analgesic to relieve pain depends on several factors, such as the drug, the dose, the route of administration, the type of pain, the patient, and the length of time the drug has been administered. Morphine is the most widely used opioid and an effective drug for moderately severe to severe pain. Morphine is considered the prototype or “model” narcotic. Morphine’s actions, uses, and ability to relieve pain are the standards to which other narcotic analgesics are often compared.Other narcotics, such as meperidine and levorphanol, are effective for the treatment of moderate to severe pain. For mild to moderate pain, the primary health care provider may order a narcotic such as codeine or pentazocine.
In addition to the relief or management of moderate to severe acute and chronic pain, the narcotic analgesics may be used for the following reasons:
• To lessen anxiety and sedate the patient before surgery. Patients who are relaxed and sedated when
anesthesia is given are easier to anesthetize (requiring a smaller dose of an induction anesthetic), as
well as easier to maintain under anesthesia
• Support of anesthesia (ie, as an adjunct during
anesthesia)
• Obstetrical analgesia
• Relief of anxiety in patients with dyspnea associated
with pulmonary edema
• Intrathecally or epidurally for pain relief for
extended periods without apparent loss of motor,
sensory, or sympathetic function
• Relief of pain associated with a myocardial infarc-
tion (morphine)
• Management of opiate dependence (levomethadyl)
• Detoxification of and temporary maintenance of
narcotic addiction (methadone)
• To induce conscious sedation before a diagnostic
or therapeutic procedure in the hospital setting
• Treatment of severe diarrhea and intestinal
cramping (camphorated tincture of opium)
• Relief of severe, persistent cough (codeine, although
the drug’s use has declined)

Use in Management of Opioid Dependence

Two opioids are used in the treatment and management of opiate dependence: levomethadyl and methadone.Levomethadyl is given in an opiate dependency clinic to maintain control over the delivery of the drug. Because of its potential for serious and life-threatening proarrhythmic effects, levomethadyl is reserved for use in the treatment of addicted patients who have no response to other treatments. Levomethadyl is not taken daily; the drug is administered three times a week (Monday/Wednesday/Thursday or uesday/Thursday/
Saturday). Daily use of the usual dose will cause serious overdose.
Methadone, a synthetic narcotic, may be used for the relief of pain, but it also is used in the detoxifi-cation and maintenance treatment of those addicted to narcotics. Detoxification involves withdrawing the patient from the narcotic while preventing withdrawal symptoms.Maintenance therapy is designed to reduce the
patient’s desire to return to the drug that caused addic-tion, as well as to prevent withdrawal symptoms. The dosages used vary with the patient, the length of time the individual has been addicted, and the average amount of drug used each day. Patients enrolled in an outpatient methadone program for detoxification or
maintenance therapy on methadone must continue to receive methadone when hospitalized.

ADVERSE REACTIONS

The adverse reactions differ according to whether the narcotic analgesic acts as an agonist or as an agonistantagonist.
Agonists
One of the major hazards of narcotic administration is respiratory depression, with a decrease in the respira-
tory rate and depth. The most common adverse reactions include light-headedness, dizziness, sedation, constipation, anorexia, nausea, vomiting, and sweating.
When these effects occur, the primary health care provider may lower the dose in an effort to eliminate or
decrease the intensity of the adverse reaction. Other adverse reactions that may be seen with the administration of an agonist narcotic analgesic include:
• Central nervous system—euphoria, weakness,headache, pinpoint pupils, insomnia, agitation,tremor, and impairment of mental and physical tasks
• Gastrointestinal—dry mouth and biliary tractspasms
• Cardiovascular—flushing of the face, peripheral circulatory collapse, tachycardia, bradycardia, and palpitations
• Genitourinary—spasms of the ureters and bladder sphincter, urinary retention or hesitancy
• Allergic—pruritus, rash, and urticaria
• Other—physical dependence, pain at injection site, and local tissue irritation

Agonist-Antagonists
Administration of a narcotic agonist-antagonist may result in symptoms of narcotic withdrawal in those addicted to narcotics. Other adverse reactions associated with the administration of a narcotic agonist antagonist include sedation, nausea, vomiting, sweating, headache,vertigo, dry mouth, euphoria, and dizziness.

CONTRAINDICATIONS

All narcotic analgesics are contraindicated in patients with known hypersensitivity to the drugs. These drugs are contraindicated in patients with acute bronchial asthma, emphysema, or upper airway obstruction and
in patients with head injury or increased intracranial pressure. The drugs are also contraindicated in patients with convulsive disorders, severe renal or hepatic dysfunction, acute ulcerative colitis, and increased intracranial pressure. The narcotic anal-gesics are Pregnancy Category C drugs (oxycodone,Category B) and are not recommended for use during pregnancy or labor (may prolong labor or cause respi-ration depression of the neonate). The use of narcotic analgesics is recommended during pregnancy only if the benefit to the mother outweighs the potential harm to the fetus.

PRECAUTIONS

These drugs are used cautiously in the elderly and in patients with undiagnosed abdominal pain, liver dis-ease, history of addiction to the opioids, hypoxia,supraventricular tachycardia, prostatic hypertrophy, and renal or hepatic impairment. The obese must be monitored closely for respiratory depression while tak-ing the narcotic analgesics. The drug is used cautiously during lactation (wait at least 4 to 6 hours after taking the drug to breastfeed the infant). The narcotics are used cautiously in patients undergoing biliary surgery because the drug may cause spasm of the sphincter of Oddi.

INTERACTIONS
 The narcotic analgesics potentiate the central nervous system (CNS) depressant properties of other CNS
depressants, such as alcohol, antihistamines, antide-pressants, sedatives, phenothiazines, and monoamine oxidase inhibitors. Use of the narcotic analgesics within 14 days of the MAO inhibitors may potentiate the effect of either drug. Patients taking the agonist-antagonist narcotic analgesics may experience withdrawal symptoms if the patient has been abusing or using narcotics. The agonist-antagonists drugs can cause opioid with drawal symptoms in those who are physically dependent on the opioids. There is an increased risk of respiratory depression, hypotension, and sedation when narcotic analgesics are administered too soon after barbiturate general anesthesia.

Read More »

Unknown Clinical Pharmacology, Narcotic Analgesics

An Antiemetic Antivertigo Medication Used To Treat Vertigo Nausea and Vomiting

An antiemetic drug is used to treat or prevent nausea (unpleasant gastric sensation usually preceding vomit-ing) or vomiting (forceful expulsion of gastric contents through the mouth). An antivertigo drug is used to treat or prevent vertigo (a feeling of a spinning or rotation- type motion) that may occur with motion sickness,Ménière’s disease of the ear, middle and inner ear surgery, and other disorders.Vomiting caused by drugs, radiation, and metabolic disorders usually occurs because of stimulation of the chemoreceptor trigger zone (CTZ), a group of nerve fibers located on the surface of the fourth ventricle of the brain. When these fibers are stimulated by chemicals,such as drugs or toxic substances, impulses are sent to the vomiting center located in the medulla. The vomiting center may also be directly stimulated by disorders such as gastrointestinal irritation, motion sickness, and vestibu-lar neuritis (inflammation of the vestibular nerve).

ACTIONS
These drugs appear to act primarily by inhibiting the CTZ or by depressing the sensitivity of the vestibular apparatus of the inner ear. Those that act on the CTZ are more effective for vomiting caused by stimulation of the CTZ, whereas those that act on the vestibular apparatus of the inner ear are more effective for vertigo
associated with motion sickness and middle and inner ear surgeries.

USES
Antiemetic Drugs
An antiemetic is used to prevent (prophylaxis) or treat nausea and vomiting. An example of prophylactic use is the administration of an antiemetic before surgery to prevent vomiting during the immediate postopera-tive period when the patient is recovering from anes-thesia. Another example is giving an antiemetic before administration of one or a combination of antineo-plastic drugs (drugs used in the treatment of cancer; which have a high incidence of causing vomiting.Dronabinol is the only currently available derivative of THC, which is a derivative of the active substance found in marijuana. Dronabinol is a second-line antiemetic and is used after treatment with other antiemetics has failed.
Other causes of nausea and vomiting that may be treated with an antiemetic include radiation therapy for a malignancy, bacterial and viral infections, nausea and vomiting caused by drugs, Ménière’s disease and other ear disorders, and neurological diseases and disorders. Some of these drugs also are used to trea
the nausea and vomiting seen with motion sickness Some antiemetics also are antivertigo drugs.

Antivertigo Drugs
An antivertigo drug is used to treat vertigo, which is usually accompanied by light-headedness, dizziness,and weakness. The individual often has difficulty walk-ing. Some of the causes of vertigo include high alcohol consumption during a short time, certain drugs, inner ear disease, and postural hypotension. Motion sickness (seasickness, carsickness) has similar symptoms but is caused by repetitive motion (eg, riding in an airplane,boat, or car). Both vertigo and motion sickness may result in nausea and vomiting.It is important to note that antivertigo drugs are essentially antiemetics because many of these prepara-tions, whether used for motion sickness or vertigo, also have direct or indirect antiemetic properties. They prevent the nausea and vomiting that occur because of stimulation of the vestibular apparatus in the ear.Stimulation of this apparatus results in vertigo, which is often followed by nausea and vomiting.

ADVERSE REACTIONS
The most common adverse reactions seen with these drugs are varying degrees of drowsiness. Additional adverse reactions for each drug
CONTRAINDICATIONS
The antiemetic and antivertigo drugs are contraindi-cated in patients with known hypersensitivity to these drugs, those in a coma, or those with severe central nervous system (CNS) depression. In general ,these drugs are not recommended during pregnancy,lactation, or for uncomplicated vomiting in young children.
Metoclopramide is contraindicated in patients with a seizure disorder, breast cancer,pheochromocytoma, or gastrointestinal obstruction.Prochlorperazine is contraindicated in patients with bone marrow depression, blood dyscrasia,
Parkinson’s disease, or severe liver or cardiovascular disease.Thiethylperazine is classified as Pregnancy Category X and is contraindicated during pregnancy.
PRECAUTIONS
Severe nausea and vomiting should not be treated with antiemetic drugs alone. The cause of the vomiting must be investigated. Antiemetic drugs may hamper the diagnosis of disorders such as brain tumors, appendicitis, intestinal obstruction, or drug toxicity (eg, dig-italis toxicity). Delayed diagnosis of any of these dis-orders could have serious consequences for the patient.Antiemetics and antivertigo drugs are used cau-tiously in patients with glaucoma or obstructive disease of the gastrointestinal or genitourinary system, those with renal or hepatic dysfunction, and in older men with possible prostatic hypertrophy. Promethazine is used cautiously in patients with hypertension, sleep
apnea, or epilepsy. Trimethobenzamide is used cau-tiously in children with a viral illness because it may increase the risk of Reye’s syndrome.
Perphenazine, prochlorperazine, promethazine,scopolamine, chlorpromazine, and trimethobenzamide
are Pregnancy Category C drugs. The pregnancy cate-gory of diphenidol is unknown. Other antiemetics and antivertigo drugs are classified as Pregnancy Category B
(except for thiethylperazine, which is classified as Pregnancy Category X).

INTERACTIONS
The antiemetics and antivertigo drugs may have addi-tive effects when used with alcohol and other CNS depressants such as sedatives, hypnotics, antianxiety drugs, opiates, and antidepressants. There may be addi-tive anticholinergic effects when admin-istered with drugs that have anticholinergic activity such as the antihistamines, antidepressants, pheno-thiazines, and disopyramide. The antacids decrease absorption of the antiemetics.When ondansetron is administered with rifampin,blood levels of ondansetron may be reduced, decreas-ing the antiemetic effect. Dimenhydrinate may mask the signs and symptoms of ototoxicity when adminis-tered with ototoxic drugs, such as the aminoglycosides, causing irreversible hearing damage.When lithium is administered with prochlorperazine,the risk of extrapyramidal reactions increases

Read More »

Unknown An Antiemetic Antivertigo Medication, Clinical Pharmacology