diff --git a/DESCRIPTION b/DESCRIPTION
index 3b813c38..7cfea7f5 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -44,7 +44,6 @@ Imports:
     future,
     methods,
     mvtnorm,
-    rlang,
     stats,
     survival,
     utils
diff --git a/NAMESPACE b/NAMESPACE
index 6555d7ec..e7d91907 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -42,7 +42,6 @@ importFrom(future,plan)
 importFrom(methods,is)
 importFrom(mvtnorm,GenzBretz)
 importFrom(mvtnorm,pmvnorm)
-importFrom(rlang,is_installed)
 importFrom(survival,Surv)
 importFrom(survival,is.Surv)
 importFrom(survival,survfit)
diff --git a/R/get_analysis_date.R b/R/get_analysis_date.R
index 07a3a0cd..e3cab3f9 100644
--- a/R/get_analysis_date.R
+++ b/R/get_analysis_date.R
@@ -69,7 +69,7 @@
 #'
 #' @export
 #'
-#' @examplesIf rlang::is_installed("gsDesign2")
+#' @examplesIf requireNamespace("gsDesign2", quietly = TRUE)
 #' library(gsDesign2)
 #'
 #' alpha <- 0.025
diff --git a/R/get_cut_date_by_event.R b/R/get_cut_date_by_event.R
index b537c19b..4182e1d3 100644
--- a/R/get_cut_date_by_event.R
+++ b/R/get_cut_date_by_event.R
@@ -29,7 +29,7 @@
 #'
 #' @export
 #'
-#' @examplesIf rlang::is_installed("dplyr")
+#' @examplesIf requireNamespace("dplyr", quietly = TRUE)
 #' library(dplyr)
 #'
 #' # Use default enrollment and calendar cut date
diff --git a/R/randomize_by_fixed_block.R b/R/randomize_by_fixed_block.R
index 0af27f95..86aacee1 100644
--- a/R/randomize_by_fixed_block.R
+++ b/R/randomize_by_fixed_block.R
@@ -32,7 +32,7 @@
 #'
 #' @export
 #'
-#' @examplesIf rlang::is_installed("dplyr")
+#' @examplesIf requireNamespace("dplyr", quietly = TRUE)
 #' library(dplyr)
 #'
 #' # Example 1
diff --git a/R/sim_fixed_n.R b/R/sim_fixed_n.R
index c52d1090..1d2b34d9 100644
--- a/R/sim_fixed_n.R
+++ b/R/sim_fixed_n.R
@@ -73,7 +73,7 @@
 #'
 #' @export
 #'
-#' @examplesIf rlang::is_installed("dplyr")
+#' @examplesIf requireNamespace("dplyr", quietly = TRUE)
 #' library(dplyr)
 #' library(future)
 #'
diff --git a/R/sim_gs_n.R b/R/sim_gs_n.R
index 60eda972..1aff59cb 100644
--- a/R/sim_gs_n.R
+++ b/R/sim_gs_n.R
@@ -42,7 +42,7 @@
 #'
 #' @export
 #'
-#' @examplesIf rlang::is_installed("gsDesign2")
+#' @examplesIf requireNamespace("gsDesign2", quietly = TRUE)
 #' library(gsDesign2)
 #'
 #' # Parameters for enrollment
diff --git a/R/sim_pw_surv.R b/R/sim_pw_surv.R
index 485dfe2e..d0e1730c 100644
--- a/R/sim_pw_surv.R
+++ b/R/sim_pw_surv.R
@@ -60,7 +60,7 @@
 #'
 #' @export
 #'
-#' @examplesIf rlang::is_installed("dplyr")
+#' @examplesIf requireNamespace("dplyr", quietly = TRUE)
 #' library(dplyr)
 #'
 #' # Example 1
diff --git a/R/simtrial-package.R b/R/simtrial-package.R
index 8327f1b9..6c225d57 100644
--- a/R/simtrial-package.R
+++ b/R/simtrial-package.R
@@ -24,7 +24,3 @@ NULL
 
 #' @importFrom Rcpp sourceCpp
 NULL
-
-# For safeguarding code examples and tests
-#' @importFrom rlang is_installed
-NULL
diff --git a/R/wlr_weight.R b/R/wlr_weight.R
index 106a73fe..5d4223ec 100644
--- a/R/wlr_weight.R
+++ b/R/wlr_weight.R
@@ -93,7 +93,7 @@ mb <- function(delay = 4, w_max = Inf) {
 #' "Designing therapeutic cancer vaccine trials with delayed treatment effect."
 #' @export
 #'
-#' @examplesIf rlang::is_installed("gsDesign2")
+#' @examplesIf requireNamespace("gsDesign2", quietly = TRUE)
 #' library(gsDesign2)
 #'
 #' # Example 1: Unstratified ----
diff --git a/man/early_zero.Rd b/man/early_zero.Rd
index f77ddfd3..44b47fa1 100644
--- a/man/early_zero.Rd
+++ b/man/early_zero.Rd
@@ -19,7 +19,7 @@ A list of parameters of the zero early weighting function
 Zero early weighting function
 }
 \examples{
-\dontshow{if (rlang::is_installed("gsDesign2")) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
+\dontshow{if (requireNamespace("gsDesign2", quietly = TRUE)) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
 library(gsDesign2)
 
 # Example 1: Unstratified ----
diff --git a/man/get_analysis_date.Rd b/man/get_analysis_date.Rd
index 0732e9b9..7e4ac335 100644
--- a/man/get_analysis_date.Rd
+++ b/man/get_analysis_date.Rd
@@ -79,7 +79,7 @@ dates determined solely by Condition 1, Condition 2, Condition 3,
 Condition 4 and Condition 5, respectively.
 }
 \examples{
-\dontshow{if (rlang::is_installed("gsDesign2")) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
+\dontshow{if (requireNamespace("gsDesign2", quietly = TRUE)) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
 library(gsDesign2)
 
 alpha <- 0.025
diff --git a/man/get_cut_date_by_event.Rd b/man/get_cut_date_by_event.Rd
index 51615aa0..70145a85 100644
--- a/man/get_cut_date_by_event.Rd
+++ b/man/get_cut_date_by_event.Rd
@@ -20,7 +20,7 @@ is never reached, the final \code{cte} at which an event occurs.
 Get date at which an event count is reached
 }
 \examples{
-\dontshow{if (rlang::is_installed("dplyr")) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
+\dontshow{if (requireNamespace("dplyr", quietly = TRUE)) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
 library(dplyr)
 
 # Use default enrollment and calendar cut date
diff --git a/man/randomize_by_fixed_block.Rd b/man/randomize_by_fixed_block.Rd
index abea25e4..4e2a2684 100644
--- a/man/randomize_by_fixed_block.Rd
+++ b/man/randomize_by_fixed_block.Rd
@@ -23,7 +23,7 @@ The final block will be a partial block if \code{n} is not an exact multiple
 of the block length.
 }
 \examples{
-\dontshow{if (rlang::is_installed("dplyr")) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
+\dontshow{if (requireNamespace("dplyr", quietly = TRUE)) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
 library(dplyr)
 
 # Example 1
diff --git a/man/sim_fixed_n.Rd b/man/sim_fixed_n.Rd
index 90d7ded7..96db5bec 100644
--- a/man/sim_fixed_n.Rd
+++ b/man/sim_fixed_n.Rd
@@ -82,7 +82,7 @@ for data cutoff:
 }
 }
 \examples{
-\dontshow{if (rlang::is_installed("dplyr")) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
+\dontshow{if (requireNamespace("dplyr", quietly = TRUE)) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
 library(dplyr)
 library(future)
 
diff --git a/man/sim_gs_n.Rd b/man/sim_gs_n.Rd
index 654f170b..103a39ad 100644
--- a/man/sim_gs_n.Rd
+++ b/man/sim_gs_n.Rd
@@ -63,7 +63,7 @@ WARNING: This experimental function is a work-in-progress. The function
 arguments will change as we add additional features.
 }
 \examples{
-\dontshow{if (rlang::is_installed("gsDesign2")) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
+\dontshow{if (requireNamespace("gsDesign2", quietly = TRUE)) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
 library(gsDesign2)
 
 # Parameters for enrollment
diff --git a/man/sim_pw_surv.Rd b/man/sim_pw_surv.Rd
index b809b1f0..b1563e1c 100644
--- a/man/sim_pw_surv.Rd
+++ b/man/sim_pw_surv.Rd
@@ -65,7 +65,7 @@ Default arguments are set up to allow very simple implementation of
 a non-proportional hazards assumption for an unstratified design.
 }
 \examples{
-\dontshow{if (rlang::is_installed("dplyr")) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
+\dontshow{if (requireNamespace("dplyr", quietly = TRUE)) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
 library(dplyr)
 
 # Example 1
diff --git a/vignettes/arbitrary-hazard.Rmd b/vignettes/arbitrary-hazard.Rmd
index 5ee1b1a8..8bd76977 100644
--- a/vignettes/arbitrary-hazard.Rmd
+++ b/vignettes/arbitrary-hazard.Rmd
@@ -16,7 +16,8 @@ knitr::opts_chunk$set(
   out.width = "100%"
 )
 
-run <- if (rlang::is_installed(c("dplyr", "ggplot2"))) TRUE else FALSE
+run <- requireNamespace("dplyr", quietly = TRUE) &&
+  requireNamespace("ggplot2", quietly = TRUE)
 knitr::opts_chunk$set(eval = run)
 ```
 
diff --git a/vignettes/maxcombo.Rmd b/vignettes/maxcombo.Rmd
index ce133d14..626dbf8f 100644
--- a/vignettes/maxcombo.Rmd
+++ b/vignettes/maxcombo.Rmd
@@ -14,7 +14,8 @@ knitr::opts_chunk$set(
   comment = "#>"
 )
 
-run <- if (rlang::is_installed(c("dplyr", "gt"))) TRUE else FALSE
+run <- requireNamespace("dplyr", quietly = TRUE) &&
+  requireNamespace("gt", quietly = TRUE)
 knitr::opts_chunk$set(eval = run)
 ```
 
diff --git a/vignettes/modest-wlrt.Rmd b/vignettes/modest-wlrt.Rmd
index eecc0867..66e7abdc 100644
--- a/vignettes/modest-wlrt.Rmd
+++ b/vignettes/modest-wlrt.Rmd
@@ -14,7 +14,7 @@ knitr::opts_chunk$set(
   comment = "#>"
 )
 
-run <- if (rlang::is_installed(c("dplyr"))) TRUE else FALSE
+run <- requireNamespace("dplyr", quietly = TRUE)
 knitr::opts_chunk$set(eval = run)
 ```
 
diff --git a/vignettes/rmst.Rmd b/vignettes/rmst.Rmd
index 9880dd79..4ecf99aa 100644
--- a/vignettes/rmst.Rmd
+++ b/vignettes/rmst.Rmd
@@ -14,7 +14,8 @@ knitr::opts_chunk$set(
   comment = "#>"
 )
 
-run <- if (rlang::is_installed(c("gt", "survRM2"))) TRUE else FALSE
+run <- requireNamespace("gt", quietly = TRUE) &&
+  requireNamespace("survRM2", quietly = TRUE)
 knitr::opts_chunk$set(eval = run)
 ```
 
diff --git a/vignettes/routines.Rmd b/vignettes/routines.Rmd
index 60556758..07951bfb 100644
--- a/vignettes/routines.Rmd
+++ b/vignettes/routines.Rmd
@@ -14,7 +14,8 @@ knitr::opts_chunk$set(
   comment = "#>"
 )
 
-run <- if (rlang::is_installed(c("dplyr", "gt"))) TRUE else FALSE
+run <- requireNamespace("dplyr", quietly = TRUE) &&
+  requireNamespace("gt", quietly = TRUE)
 knitr::opts_chunk$set(eval = run)
 ```