First-Pass Metabolism - Revision history

102343832 at 18:06, 14 November 2011

2011-11-14T18:06:52Z

← Older revision		Revision as of 18:06, 14 November 2011
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	This form of metabolism is therapeutically relevant as...		This form of metabolism is therapeutically relevant as...

	#It implies that the [[Drug Efficacy\|efficacy]] of a drug is lower when its route of administration is oral rather than intravenous. <ref ~~name="null"~~>Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>This frequently means that a higher dose is used when a drug is administered orally <ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>. First-pass metabolism can reduce the bioavailability of some drugs to the extent that it renders them completely ineffective and makes oral administration unsuitable ([[Insulin\|insulin]] is an example of this) <ref>Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>.		#It implies that the [[Drug Efficacy\|efficacy]] of a drug is lower when its route of administration is oral rather than intravenous.<ref>Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref> This frequently means that a higher dose is used when a drug is administered orally <ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>. First-pass metabolism can reduce the bioavailability of some drugs to the extent that it renders them completely ineffective and makes oral administration unsuitable ([[Insulin\|insulin]] is an example of this) <ref>Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>.
	#First-Pass Metabolism differs between people <ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>.		#First-Pass Metabolism differs between people <ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>.

102343832 at 18:01, 14 November 2011

2011-11-14T18:01:50Z

← Older revision		Revision as of 18:01, 14 November 2011
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	First-pass metabolism (also known as presystemic [[Metabolism\|metabolism]]) refers to the action of metabolic [[Enzyme\|enzymes]], in the [[Liver\|liver]] and gut wall, on drugs <ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>. These enzymes metabolise drugs before they enter the [[Systemic Circulation\|systemic circulation]], often rendering a fraction of the drug inactive <ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>. This lowers the proportion of an ingested drug that is acquired by the systemic circulation in its active form (its [[Bioavailability\|bioavailability]]).<ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc</ref>		First-pass metabolism (also known as presystemic [[Metabolism\|metabolism]]) refers to the action of metabolic [[Enzyme\|enzymes]], in the [[Liver\|liver]] and gut wall, on drugs <ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>. These enzymes metabolise drugs before they enter the [[Systemic Circulation\|systemic circulation]], often rendering a fraction of the drug inactive <ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>. This lowers the proportion of an ingested drug that is acquired by the systemic circulation in its active form (its [[Bioavailability\|bioavailability]]).<ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>

	This form of metabolism is therapeutically relevant as...		This form of metabolism is therapeutically relevant as...

	#It implies that the [[Drug Efficacy\|efficacy]] of a drug is lower when its route of administration is oral rather than intravenous. <ref name="null">Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>This frequently means that a higher dose is used when a drug is administered orally <ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>. First-pass metabolism can reduce the bioavailability of some drugs to the extent that it renders them completely ineffective and makes oral administration unsuitable ([[Insulin\|insulin]] is an example of this) <ref>Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>.		#It implies that the [[Drug Efficacy\|efficacy]] of a drug is lower when its route of administration is oral rather than intravenous. <ref name="null">Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>This frequently means that a higher dose is used when a drug is administered orally <ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>. First-pass metabolism can reduce the bioavailability of some drugs to the extent that it renders them completely ineffective and makes oral administration unsuitable ([[Insulin\|insulin]] is an example of this) <ref>Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>.
	#First-Pass Metabolism differs between people <ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>.		#First-Pass Metabolism differs between people <ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>.

	=== References ===		=== References ===

102343832 at 17:59, 14 November 2011

2011-11-14T17:59:17Z

← Older revision		Revision as of 17:59, 14 November 2011
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	First-pass metabolism (also known as presystemic [[Metabolism\|metabolism]]) refers to the action of metabolic [[Enzyme\|enzymes]], in the [[Liver\|liver ~~and~~]] gut wall, on drugs <ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>. These enzymes metabolise drugs before they enter the [[Systemic Circulation\|systemic circulation]], often rendering a fraction of the drug inactive <ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>. This lowers the proportion of an ingested drug that is acquired by the systemic circulation in its active form (its [[Bioavailability\|bioavailability]]).<ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc</ref>		First-pass metabolism (also known as presystemic [[Metabolism\|metabolism]]) refers to the action of metabolic [[Enzyme\|enzymes]], in the [[Liver\|liver]] and gut wall, on drugs <ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>. These enzymes metabolise drugs before they enter the [[Systemic Circulation\|systemic circulation]], often rendering a fraction of the drug inactive <ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>. This lowers the proportion of an ingested drug that is acquired by the systemic circulation in its active form (its [[Bioavailability\|bioavailability]]).<ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc</ref>

	This form of metabolism is therapeutically relevant as...		This form of metabolism is therapeutically relevant as...

102343832 at 17:58, 14 November 2011

2011-11-14T17:58:35Z

← Older revision		Revision as of 17:58, 14 November 2011
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	This form of metabolism is therapeutically relevant as...		This form of metabolism is therapeutically relevant as...

	#It implies that the [[Drug Efficacy\|efficacy]] of a drug is lower when its route of administration is oral rather than intravenous. <ref name="null">Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>This frequently means that a higher dose is used when a drug is administered orally <ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>. First-pass metabolism can reduce the bioavailability of some drugs to the extent that it renders them completely ineffective and makes oral administration unsuitable ([[Insulin\|insulin]] is an example of this) <ref>Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>.		#It implies that the [[Drug Efficacy\|efficacy]] of a drug is lower when its route of administration is oral rather than intravenous. <ref name="null">Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>This frequently means that a higher dose is used when a drug is administered orally <ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>. First-pass metabolism can reduce the bioavailability of some drugs to the extent that it renders them completely ineffective and makes oral administration unsuitable ([[Insulin\|insulin]] is an example of this) <ref>Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>.
	#First-Pass Metabolism differs between people <ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>.		#First-Pass Metabolism differs between people <ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>.

	=== References ===		=== References ===

	<references />		<references />

Nnjm2 at 17:57, 14 November 2011

2011-11-14T17:57:27Z

← Older revision		Revision as of 17:57, 14 November 2011
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	First-pass metabolism (also known as presystemic metabolism) refers to the action of metabolic [[Enzyme\|enzymes]], in the [[Liver\|liver ]]~~and~~ gut wall, on drugs.<ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>These enzymes metabolise drugs before they enter the [[Systemic Circulation\|systemic circulation]], often rendering a fraction of the drug inactive.<ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref> This lowers the proportion of an ingested drug that is acquired by the systemic circulation in its active form (its [[Bioavailability\|bioavailability]]).<ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc</ref>		First-pass metabolism (also known as presystemic [[Metabolism\|metabolism]]) refers to the action of metabolic [[Enzyme\|enzymes]], in the [[Liver\|liver and]] gut wall, on drugs <ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>. These enzymes metabolise drugs before they enter the [[Systemic Circulation\|systemic circulation]], often rendering a fraction of the drug inactive <ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>. This lowers the proportion of an ingested drug that is acquired by the systemic circulation in its active form (its [[Bioavailability\|bioavailability]]).<ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc</ref>

	This form of metabolism is therapeutically relevant as...		This form of metabolism is therapeutically relevant as...

	1) It implies that the [[Drug Efficacy\|efficacy]] of a drug is lower when its route of administration is oral rather than intravenous. <ref name="null">Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>This frequently means that a higher dose is used when a drug is administered orally.<ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref> First-pass metabolism can reduce the bioavailability of some drugs to the extent that it renders them completely ineffective and makes oral administration unsuitable ([[Insulin\|insulin]] is an example of this).<ref>Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>		#It implies that the [[Drug Efficacy\|efficacy]] of a drug is lower when its route of administration is oral rather than intravenous. <ref name="null">Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>This frequently means that a higher dose is used when a drug is administered orally <ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>. First-pass metabolism can reduce the bioavailability of some drugs to the extent that it renders them completely ineffective and makes oral administration unsuitable ([[Insulin\|insulin]] is an example of this) <ref>Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>.
			#First-Pass Metabolism differs between people <ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>.

	~~2) First-Pass Metabolism differs between people. <ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>~~		=== References ===

	~~ ~~ <references />		<references />

102343832 at 17:46, 14 November 2011

2011-11-14T17:46:32Z

← Older revision		Revision as of 17:46, 14 November 2011
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	First-pass metabolism (also known as presystemic metabolism) refers to the action of metabolic [[Enzyme\|enzymes]], in the liver and gut wall, on drugs.<ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>These enzymes metabolise drugs before they enter the [[Systemic Circulation\|systemic circulation~~<span id="fck_dom_range_temp_1321292465940_626" />~~]], often rendering a fraction of the drug inactive.<ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref> This lowers the proportion of an ingested drug that is acquired by the systemic circulation in its active form (its [[Bioavailability\|bioavailability]]).<ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc</ref>		First-pass metabolism (also known as presystemic metabolism) refers to the action of metabolic [[Enzyme\|enzymes]], in the [[Liver\|liver ]]and gut wall, on drugs.<ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>These enzymes metabolise drugs before they enter the [[Systemic Circulation\|systemic circulation]], often rendering a fraction of the drug inactive.<ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref> This lowers the proportion of an ingested drug that is acquired by the systemic circulation in its active form (its [[Bioavailability\|bioavailability]]).<ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc</ref>

	This form of metabolism is therapeutically relevant as...		This form of metabolism is therapeutically relevant as...

102343832 at 17:43, 14 November 2011

2011-11-14T17:43:52Z

← Older revision		Revision as of 17:43, 14 November 2011
Line 1:		Line 1:
	First-pass metabolism (also known as presystemic metabolism) refers to the action of metabolic enzymes, in the liver and gut wall, on drugs.<ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>These enzymes metabolise drugs before they enter the systemic circulation, often rendering a fraction of the drug inactive.<ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref> This lowers the proportion of an ingested drug that is acquired by the systemic circulation in its active form (its bioavailability).<ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc</ref~~><br~~>		First-pass metabolism (also known as presystemic metabolism) refers to the action of metabolic [[Enzyme\|enzymes]], in the liver and gut wall, on drugs.<ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>These enzymes metabolise drugs before they enter the [[Systemic Circulation\|systemic circulation<span id="fck_dom_range_temp_1321292465940_626" />]], often rendering a fraction of the drug inactive.<ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref> This lowers the proportion of an ingested drug that is acquired by the systemic circulation in its active form (its [[Bioavailability\|bioavailability]]).<ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc</ref>

	This form of metabolism is therapeutically relevant as...		This form of metabolism is therapeutically relevant as...

	1) It implies that the efficacy of a drug is lower when its route of administration is oral rather than intravenous. <ref name="null">Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>This frequently means that a higher dose is used when a drug is administered orally.<ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref> First-pass metabolism can reduce the bioavailability of some drugs to the extent that it renders them completely ineffective and ~~thus~~ oral administration unsuitable (insulin is an example of this).<ref>Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>		1) It implies that the [[Drug Efficacy\|efficacy]] of a drug is lower when its route of administration is oral rather than intravenous. <ref name="null">Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>This frequently means that a higher dose is used when a drug is administered orally.<ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref> First-pass metabolism can reduce the bioavailability of some drugs to the extent that it renders them completely ineffective and makes oral administration unsuitable ([[Insulin\|insulin]] is an example of this).<ref>Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>

	2) First-Pass Metabolism differs between people. <ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>		2) First-Pass Metabolism differs between people. <ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>

102343832: Created page with "First-pass metabolism (also known as presystemic metabolism) refers to the action of metabolic enzymes, in the liver and gut wall, on drugs.Rang H, Dale M, Ritter J, Fl..."

2011-11-14T17:39:04Z

Created page with "First-pass metabolism (also known as presystemic metabolism) refers to the action of metabolic enzymes, in the liver and gut wall, on drugs.<ref>Rang H, Dale M, Ritter J, Fl..."

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First-pass metabolism (also known as presystemic metabolism) refers to the action of metabolic enzymes, in the liver and gut wall, on drugs.<ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>These enzymes metabolise drugs before they enter the systemic circulation, often rendering a fraction of the drug inactive.<ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref> This lowers the proportion of an ingested drug that is acquired by the systemic circulation in its active form (its bioavailability).<ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc</ref><br>

This form of metabolism is therapeutically relevant as...

1) It implies that the efficacy of a drug is lower when its route of administration is oral rather than intravenous. <ref name="null">Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref>This frequently means that a higher dose is used when a drug is administered orally.<ref name="null">Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref> First-pass metabolism can reduce the bioavailability of some drugs to the extent that it renders them completely ineffective and thus oral administration unsuitable (insulin is an example of this).<ref>Grahame-Smith D, Aronson J. (2002) Oxford Textbook of Clinical Pharmacology and Drug Therapy, 3rd Edition, Hong Kong: Oxford University Press.</ref> 

2) First-Pass Metabolism differs between people. <ref>Rang H, Dale M, Ritter J, Flower R and Henderson G. (2012) Rang and Dale's Pharmacology, 7th Edition, Spain: Elsevier Inc.</ref>

  <references />

 